Sunday, July 24, 2016

Project #5 - 240 mm D2 gyuto

With first relative success with grinding smaller kitchen knife (see Project #3) I decided to give a 'full size' gyuto a try. This project proved to be very labor intensive, but I learned a lot as well. Even though it is a long article - do check out 'Lessons learned' at the end.

Design

I have taken part in a pass-around organized by Dan Prednergast (via KitchenKnifeForums.com) and loved the profile and grind of the blade and decided to use it as starting point for this knife.

Basic numbers
  • Japanese style kitchen knife (gyuto) with 240 mm cutting edge
  • 50 mm tall blade
  • Continuous convex grind
  • D2 steel
  • WA style handle

One of the challenges apart from the size (and thus long grinding times) was to get the grind of the knife as close to final prior to heat treatment as possible. The reason for that is - when I started to work on this knife I did not have a belt grinder yet (I got a small 1x30" while the project was ongoing) and I have learned already, that changing the grind (thinning) after heat treatment can easily take 5 - 10 hours with an Atoma 140 diamond plate and I wanted to keep that to minimum. Still - I would not grind the edge to zero thickness to minimize possible warping during the quench.

Making the blank

(I somehow did not take photos during this part of the process, sorry for that)

Once I was happy with the design I traced in on the steel. Since the steel was only 50 mm wide, the knife could not quite get the same width - I managed to get about 49 mm.

I have used a hack saw to cut out the blank. With knife this long it proved very helpful to be able to set the blade under 45° angle relative to the plane of the saw - so that the frame would clear from the blank itself. Still - it took me quite a while to cut the blank out - about an hour.

Tip: Do not use D2 steel for you first large knife - it is rather abrasion resistive and will make all cutting, grinding and sanding steps take longer. Simple carbon steel is the best way to go with hand ground knives. If you have a belt grinder this will be less of an issue.

Here I made a first mistake - I have cut little too much just few centimetres from the heel and it took me a lot if time afterwards to remove this mistake with a coarse file, since I had to file the whole cutting edge to preserve the designed profile.

I have left the tang considerably wider than what it would be once finished - the reason was to have better mechanical stability while grinding the bevels. I would only cut the tang to its final shape once the bevels were ground and then finish the surface of the whole knife before heat treat.

Once the blank was finished I have scribed a center line on both the spine and the cutting edge so that it would be easier to keep en eye on the left-right symmetry during the grinding.

Grinding the bevels with a jig

Since I had some lessons learned from the Project #3, I realized that I need to be more careful with the grinding angles. My idea to produce a more-less continuous convex grind (i.e. not a full flat grind which is not a good choice for kitchen knives in general) was to approximate the convex shape with 3 planes and blend them in a later stage.

The idea is represented with the figure below.

  1. grind -  should be done under such angle, that once the edge has the desired thickness, the bevel should at the same time have the desired width.
  2. grind - would push the bevel further up, but would stop about 5 mm from the edge
  3. grind - would push the bevel even more further up and stop about 10 mm from the edge.
Grinding strategy with the filing jig. Yellow line is the intended final blade geometry.
Not to scale :)

In the photo above:

d1 - 1/2 of the thickness of the edge prior to heat treat ~ 0.15 - 0.2 mm
d2 - 1/2 of the thickness 5 mm (w2) from the cutting edge prior to heat treat ~ 0.35 - 0.4 mm
d3 - 1/2 of the thickness 10 mm (w3) from the cutting edge ~ 0.6 - 0.65 mm
a1 - first grinding angle ~ 2.4°
a2 - first grinding angle ~ 1.6°
a3 - first grinding angle ~ 0.8°


The above strategy would, before following hand filing would be done, yield a rough approximation of the convex bevel AND would lay the base for the distal taper, because after the 3rd grind the bevels would hit the spine somewhere 1/2 way between the handle and the tip.

One needs to realize here that while you can calculate the approximate angle under which you want to grind the first bevel, it may not be practically possible to grind under that angle because you have flex in the system - the holder is made out of wood, the blank is long and thin, the file is attached to a long steel bar which will flex slightly under pressure (and thus will give you variation of the effective grinding angle). This means that one should keep checking the width of the bevel as the grinding proceeds and check whether it develops as expected. Now should you find out that your grinding angle is small or larger than planned (meaning you are getting to the designed width of the bevel but not the edge thickness or vice versa), than just adjust it, re-paint the ground part with a permanent marker and keep grinding.

Using an angle cube to set the angle for the first of the 3 grinding steps.

My calculation gave me angle of about 2.4° per side for the primary grind. Not that may sound very little, but one should not forget, that the edge will be left with thickness of some 0.3+ mm so there will be some more grinding happening after the heat treatment, so the angle will increase somewhat. For the second grind I have used angle of about 1.6° and about 0.8° for the third. Do not take these numbers as cast in stone - you may be after very different grind that what I am trying to do here. The grinding jig has also a finite stiffness, so these values really are just approximate.

About to start the grinding. I have marked the blade to see how the progress develops. Note the wide tang at this stage.
Tip: You will need a stop pin of some sort close to the tip of the blade, so the blade does not move during the grinding (you can not clamp the tip, obviously). I simply used a brass screw. Since brass is much softer than the steel, once the spine close to tip starts to get thinner during the grinding, the head of the screw will be ground too and not get in the way, while it will keep working as a stop pin.

While grinding I would recommend moving slowly from the heel to tip and then backwards. Observe the scratch pattern to see that you remove the material more-less evenly. This will become gradually harder as the ground surface gets wider. Keep switching hands as this is quite a work-out.

You will also experience the file 'skating' on the bevel. You can try to remedy that with changing where you apply the pressure with the hand that is not holding the handle of the file. Clean your file regularly from the steel pieces that get stuck to its surface as these will cause deep scratches.


Working on the first grind. The red area show the part that should be ground. The blue should stay.

Getting close to the final width of the primary grind.






Once you have finished the first grind on one side, flip the blade over and to the same on the other side. Do not grind one side completely (all 3 grinding steps in this case) as the blade changes shape and only small part of it will remain flat (unground), so once you flip it over you do not have the same contact with the board underneath and that may (and will) influence your grinding angles. So flipping the blade more often will give you little more reproducibility.


About to finish the first grind on the right side of the blade.


Working on the third grind. Part of it was ground when going from the heel towards the tip (upper left part of the photograph). Here I am grinding from tip to heel and grinding down to about 10 mm from the edge.

Once you get the first grind (on both sides) finished you can proceed with the second one. This will be actually much less work. Again, once finish with these on both sides you move to the third grind. 2nd and 3rd grind are from principal point of view very similar - they differ only in grinding angle and in how close to the edge you want to get.


Choil shot of the blade ground with the grinding jig.
Once you have finished all 3 grinds it is time to move to free hand grinding.

Hand grinding / finishing the bevels

At this stage you have the bevels in form of 3 separate planes, the distal taper is not quite there yet either. One could try to continue with the grinding jig, but I prefer to do the rest of the pre-heat treatment grinding by hand.

For this you need a file little less coarse than the bastard file (I have used file cut #2) with length of 250 mm (10"). This gives you enough room for both hands.

As a support I have used a piece of wood with 30x60 mm cross section which I roughly shaped (with a saw and a rasp) so that its profile somewhat follows the shape of the edge. The idea is - you do NOT want the edge to stick outside the support - on one hand you do not want to hurt yourself, on the other hand you do not want to accidentally bump against the edge with some tools, because since it is thin now (we left it at around 0.3 mm) it is very easy to dent.

Draw filing setup. Notice the 'tip protector'


After previous experience I also used a small clamp placed some 10 - 15 mm (about 1/2 the width of the file) in front of the blade to serve as a tip protector. It does not allow you to slip off the blade and with the motion towards the handle severely damage the tip.

Grinding technique

Option (1) - you hold the file with your both hands, set the file flat on the blade and move along the blade. You adjust the angle with your hands what seems to work pretty well. Still - check the progress regularly and swap the sides regularly. Also - best is to paint a 5 mm wide stripe along the edge with a marker - you do not want to grind that part.

Option (2) - is very similar to the first one, but you slightly tilt the file (rotate the file around its long axis), so that you only use the edge of the file. I call it 'edge-draw'. This speeds up the process considerably, but there is a price to pay. You will get VERY deep scratches. So deep, that you should calculate some 0.3 mm on the blade thickness that will take to remove them (first using the option (1) followed by a #60 grit wet sanding paper). I did not take this into consideration what meant that until I had all these scratches removed, the blade lost several millimeters of its height.


Scratches left by 'edge-draw' grinding technique.


During the 'edge-draw' grinding these kind of fine turnings are produced.

Detailed view of the tip and the tip protector.

Choil shot after hand grinding. The scratches are not yet removed.

Since quite some time passed until I got to the point of removing those deep scratches which would have taken a very long time to remove by hand, I decided to my new 1x30" belt grinder a try. I have used the 3M Trizact 'gator' belt with grit A100 (100 micro-meters sized particles - should be comparable to 'standard' grit rating of about 200). Even this proved to be a slow process - mainly because I had zero experience with the grinder.

Most of the scratches removed, a few more to go.

I have to admit I did not anticipate how much material had to be removed to get all the scratches out. The choil shot below shows the blade becoming considerably thinner in the process.

Choil shot of the blade ready for heat treat.

Tang shaped, heel and spine sanded. The blade is ready for heat treat.


Once the blade came back from the heat treat (done by J├╝rgen Schanz) it was time to finish the bevels and make a handle. What also needed to be done was some straightening of the blade. I only use the edge of the work bench and my hands to do that, but there are better ways to do it (I got some very good advice from Jon Broida of Japanese Knife Imports) and I may post it with some future projects.

In the process of the blade straightening I managed to break off the tip of the knife (was not the first time in the process). It was minor though and easy to repair with the grinder.

Broken tip - result of the straightening process.

Blade finishing

Even though the blade was ground thinner than I wanted prior the heat treat (because of the scratch removal process) I still needed to finish the bevels close to the edge (up to about 5-10 mm from the edge) and also refinish the blade further up the blade face. I used 80 grit Sait 7S belt and and ground the blade VERY carefully as I was trying to avoid not to overheat the edge - in particular since the cutting edge was already very thin. However it turned out to be better idea to do the job with a 40 grit belt as it produced less heat.

The inevitable result of the grinding was putting a load of scratches basically over the whole blade. I have tried, but apparently failed to remove these with a progression of finer belts (#80, #120, #240). Part of the reason was that the platen of the grinder is just a thin piece of "L" shaped steel with a relative large amount of flex to it what made it hard to apply pressure to certain area of the blade (which at this stage was relatively flat). Also the limited amount of usable space on the belt did not allow me to change grinding angles and thus observe the progress of the scratch removal.

Realizing that I am not going to get any usable scratch removal on the grinder I have moved to hand sanding. Given the experience from project #3 I have covered the side facing the support with a tape (Tesa plastering tape). Since I had rather coarse scratches on the blade I had to start as low as grit #80 and it took me 30 minutes (per side).

One side of the blade completely covered with a tape to protect the
blade from being scratched while the other side is being sanded.

I have switched the sanding setup to lower the working height to where I was able to use my body weight to push down on the blade. Also - since I needed around 3 hours of sanding per side (something I was not able to do in one go) I would write a short note on the blade as to where I should continue.

Original hand sanding setup - rather flexible but too high to work comfortably.

Modified hand sanding setup to allow a more user friendly working height.

Self explanatory note :)

The scratches from the grinder were perpendicular to the edge and normally I would start hand sanding under ca 45 deg. relative to the edge. But since the scratches I needed to remove were deep (and D2 is not easy to grind or sand) I have decided to sand the blade parallel to the edge with the #80 grit to be able to sand with more pressure and less chance of slipping on the edge or spine.

Starting with the #80 grit parallel to the edge/spine.
The scratches from the belt are clearly visible.

After about 15 minutes of sanding with grit 80 sand paper.
Some more work to be done.

Once the scratches from the belt sander were removed with grit 80 sand paper I have moved up to 120, 180, 240, 320, 400 and 600 sand paper always alternating the angle of the sanding such that the subsequent scratches would be perpendicular to the once made with the previous grit. Once I got to grit 400 I would sand parallel to the knife spine, get as smooth finish as I could - including the long pull movements from the tang towards the tip without changing the direction - and then I would repeat the same with grit 600.

I have also switched from WD-40 to Windex with grit 400 and higher. I can not help but my impression was that the scratch pattern got considerably finer than what I would have expected with the change from grit 320 to 400.

Even though I have used the tape to protect the blade - some of the dirt produced during sanding would still leak-in around the edge of the blade. It turned out to be a good idea to finish both sides to the one before last grit step (400) and do the finishing strokes with 400 and 600 with just a piece of paper towel between the blade and the wooden support.

Sorry for not taking more photos from the hand sanding process, but it really is not fun work and I was lacking the motivation :)

Handle making

Since the design of the handle from the project #3 worked optically rather well, I have decided to make handle with the same design (ferrule from stabilized wood, fibre spacers and curly birch handle), the only relevant difference being that this time I went with a drill-through ferrule.  However I did manage to make some new mistakes :)

The size of the handle was based on octagonal Japanese-made burned chestnut handle on 240 Kato Workhorse (heavy duty knife with 280 g weight) which is 26 mm tall and 22 mm wide at the ferrule and a little larger at the far end. I went with a size by about 1 mm less in each direction as this knife was not going to be quite as heavy.

I have started with a nice, squared-up  block what proved to be a huge help. I will certainly try to square up the wood before starting to work on the handle next time (I do not quite have the proper tools as of today). After taking some measurements (length of the tang among other things) I have started with drilling the handle for the dowel.  Here I managed not to clamp the block properly in the vise and the resulting opening had a 'bump' mid-length. This may happen as the drill body is thinner than the head. I managed to correct it with the drill though.

Checking the alignment before drilling the handle.
The dowel was made with the same technique as in the project #3 - cutting with a wood saw and widen with the sander. I would then check the fit with the tang and the handle block to make sure they all fit together. After that I drilled the opening for the dowel in the ferule and checked together with the dowel and the handle.


Checking the fit of the tang inside the dowel.

Once all components were ready for gluing I have first glued the dowel inside the handle with a 5 minute epoxy and once the glued settled after about 30 minutes I have glued the fibres and the ferule. As it turned out I managed to get a small void on one side between the ferrule and the dowel - something to improve upon next time.

Important note - since the whole handle was clamped I had to make sure that the dowel would not stick out of the ferule as that would not allow to clamp the handle.

Gluing the dowel inside the handle. I have used a piece of scrap steel
to make sure the dowel was 'opened' while the glue was setting.

The handle was allowed to cure for 24 hours. After that I have drawn guide lines so that I could roughly shape the handle with the belt sander. I have also marked the center of the handle on the back end before I would start to grind the wood, as the lines would be removed in the process.


Handle after gluing.

Handle ready for rough shaping with the belt sander.

To rough shape the handle I would first remove excess wood on the narrow sides of the handle with 40 grit belt (that did not want to cut steel anymore, but was plenty good for wood) and flatten them on the disc sander with 80 grit. Then I would do the same for the wide sides of the handle. At this stage the handle already has the taper (the handle is lightly wider/taller at the end relative to the ferrule), but is about 1-2 mm wider & taller than the final size - to leave a margin for error, so that I could still correct some mild de-centering. I would measure the handle with a caliper and check whether the opening in the ferrule is on-center. The handle would be carefully ground to final size with the disc sander. 

Note: care needs to be taken with a disc grinder this small, as the grinding speed depends on the distance from the center. The solution is to use little pressure and move the handle back and forth and keep checking for the flatness.


Handle ground to final size and ready for final shaping.
Now the tricky part was to be done - put an octagonal shape on the handle. I still do not have any fixture for this and only use the work rest as support. I would hold the handle on both ends and very carefully and with little pressure I would start grinding the corners. I was more successful than the last time - only once did the disc grinder send the handle flying across my workshop :) The issue here is that because of the small diameter of the sander I have to use the full width, meaning that on one end of the handle there is downward force, but on the other upward - what makes it hard to make even grinds.

I would also recommend to first establish the octagonal shape, check for the symmetry and angles, and only then proceed grinding to the final shape. Most probably you will not get the angles as intended with this free-hand method and you want to have the possibility to correct.

First 3 corners ground, but only as much as to have a starting point.
Corrections are still possible as there is more material to be removed.
Once the grind of the octagonal shape was finished, the front side and back side of the ferrule would be ground to final length of the handle. Here I went with 145 mm.

The next step was hand sanding. I have used sanding paper with grits 120, 240 and 400 followed with a steel wool. To minimize the risk of grinding away the facets (edges) of the handle I have placed the sanding paper of a flat surface (piece of stone for counter top) and have used sanding strokes in just one direction. I have used small metal brush to clean the sanding paper in the process.



Sanding setup.

Once all sides of the handle were sanded to 400 I have carefully sander the front edges of the ferrule with slow motions during which I would continuously change the angle, so the final edge would be rounded. On the back side of the handle I have sanded the edges under 45 degrees. The handle was then sanded with steel wool what have a nice semi-glossy polish to the surface.

The last step was to oil the handle. As it turned out with the project #3 that just board butter did not give the surface finish I wanted, I decided to use Tru-oil here. I have used 2 coats and steel wool. I have always allowed the coat to cure for 24 hours before polishing and applying another one.

The handle was glued with a slow curing epoxy onto the tang. It was again a very slow process to get the viscous epoxy in. I am in search for a low viscosity epoxy for this purpose.

Here I managed to make one more mistake (though at this stage too late to correct) - apparently the dowel was not positioned as it should have been inside the handle - the blade is rotate a little bit relative to the handle (can be seen in the comparative choil shot below). My handle making process needs improvements.

Total time ~ 25+ hours
  • 1h - blade design 
  • 1h - cutting out the blank
  • 1h - finishing the blank with a file (removing mistakes from previous step)
  • 6h - grinding the blade with bevelling jig & free hand draw filing
  • 2h - hand & belt grinding the blade (scratch removal) prior to heat treat.
  • 6h - finishing the blade after heat treat
  • 2h - handle making
  • 1h - putting the knife together
  • 5h - all the little bits and pieces, fixtures, correcting errors, etc.


Lessons learned

There are quite some of them with this project:
  • If you are a starting knifemaker with only rudimentary tools and little skills, than do not hurry to start with a tool steel like D2 - it is very abrasion resistant what makes both grinding and sanding a lesson in patience. Simpler carbon steels will be easier to work with, but if you want use stainless than take something like AEB-L or 440C
  • When planning to work on a certain grind to achieve certain thickness of the blade (geometry) grind the blade some 0.1 - 0.2 mm thicker than the design value with the bevelling jig - and 0.3 - 0.4 mm if you plan to use draw-filing technique as you will not only remove some more material during the draw filing, but also afterwards when removing the rather deep scratches.
  • Try your best not to grind the edge too thin prior the heat treat. Yes - grinding afterwards will only be possible with diamond plate and coarse sharpening stones or a belt grinder. If you do not have a belt grinder than you are looking at several hours of work, but if you grind the edge too thin you risk damage during the heat treat. The same is true for the tip of the knife.
  • When grinding the blade after HT (thinning, etc) be careful not to overheat the edge. Use fresh, coarse (~ 40 grit) belts. Only use finer belts for scratch removal.
  • The better you manage to remove scratches with a belt grinder, the less time it will take to hand sand the blade to its final finish.
  • When hand sanding the blade - make sure that you remove all previous scratches before moving to finer grit, otherwise you will end up with otherwise nicely finished blade with a few scratches that will be screaming at you and wake you in the middle of the night :)
  • During any stage when doing hand grinding or sanding - mind the edge - do not let it stick outside the contours of the support you are using - you decrease the chance of accidentally cutting yourself or damaging the edge should your hand slip.

Finished knife

OK, it was not sharpened yet, but there is very little work to be done since all the sanding left the edge with basically zero thickness, meaning that I will have to remove very little material during the first sharpening.

The dimensions:

  • Weight 190g
  • 230 mm on edge
  • 47 mm at the heel



The Tru-Oil finish looks really nice and feels very good to touch.

600 grit hand finished blade


The blade is really thin behind the edge - between 1.0 and 1.1 mm 10 mm from the edge.

Left: Carter funayuki, Right: D2 gyuto.


Monday, June 27, 2016

The tools - part #2 - powered tools

Even though it is possible to make knives completely without powered tools, these will make your life considerably easier. so what it is that you may want/need.

Drill press

I have already mentioned it in the part #1 and only add it here for completeness. I got the Bosch PDB 40 for about 250€, but you can get a simpler drill press for half that much. I would add that you also want to get a drill vise so that you are able to safely and accurately position different parts you need to drill into. One will cost you around 30 - 50 €.




Steel cutting powered tools

Sooner or later you will find out that cutting blanks with hack saw is slow and tedious process - in particular with larger knives. So - the options are the following:

  • Dedicated metal band saw. 
  • Angle grinder. This is a relatively cheap (50€ - 70€) and fast solution. 
  • Other types of hand-held saws which hold the blade on one end only like jigsaw. Some of these are designed to cut metal, so that could be an option too. However I have no experience there, nor did I find others that would use these kind of saws.

There are also options that you should rather avoid. In the first place these are wood band saws. The problem there is not necessarily in the power of the saw, but wood band saws run with much higher speeds and use different belt blades that will dull within few seconds on metal.


Metal band Saw

These start at around 400€. Make sure you get one that can be positioned vertically and have additional working plate attached. The fully professional vertical metal band saws are in 3000+€ range and I do not consider them here a viable alternative here for cost and size reasons.

Angle grinder

You may ask yourself - what is angle grinder good for? It is indeed not a tool for a detailed work, but it can be used to cut out (roughly) blanks. This only makes sense if you have a grinder to finish the blanks as it is advisable to leave 2-3 mm of material. That much steel would take long to remove with a file, but even with a small 1x30" belt grinder it takes just a few minutes. It is also one of the cheapest tools for this job.

I have used angle grinder to cut 8 blanks (180 mm petty knives) in about 30 minutes. That would have taken much longer with a hack saw.

Before you start to grind away do not forget to use your safety gear - you do not want to breathe the freshly burned steel and steel dust or get hit by flying pieces of steel or cutting wheel in your eyes or face.

You will want to use 1 mm thick cutting discs. I have completely used 1 disc on those 8 blanks.

If you decide to get an angle grinder, get the 125 mm instead of 115 mm. They cost the same, the cutting discs cost the same, but 125 mm will last you longer. 1000 W of power is enough. Getting a weaker model does not really save you much and a stronger one is not really needed for this job (the price start to go up for more powerful models.

After 30 minutes of work.

Last but not least - there are guys who manage to grind blades with an angle grinder (I presume with the sanding discs). There are some youtube videos on how to do that (even building a grinding jig). It would not be my method of choice - if anything because of the noise, dirt/smell and potential to unnecessarily overheat the steel, but hey, it can be done.


Belt saw (for wood)

When making handles from wood (in particular hidden tang handles or WA handles) what often means that you need to remove larger amount of material from the handle before you will start with some finer shaping. There are many options how to do that and one of them is belt saw. I am planning on getting one to be able to cut large wood pieces to blocks.

Disc grinder

There are several uses for one. I currently only have a very small one - just 125mm in diameter, but it already helps me to flatten metal before cutting out the blanks or bolsters and also do some grinding on wood (squaring up blocks before further use). Should you be getting one go for a full size (300mm or 12") one. Be careful when using one - these machines like to throw things around.

Belt grinder 

When one mentions a belt grinder in the context of knifemaking, one immediately has in mind a 2x72" 2kW machine with all bells and whistles for 2000+ $ or €. Sure - that is indeed a tool of trade for many full time knifemakers, but if you are just starting you may want to have a look at a small and simple 1x30" grinder that will cost you under 100 $/€ (OK, you will soon be out more than that on belts). While not a necessity, I am finding more and more use for mine. Check out my article on 1x30" belt sanders for more details. These little machines may surprise you and considerably speed up many steps in the knife making. I am currently working on my Project #7 which is the first when I use a belt grinder to grind the bevels prior and after HT. I seem to need about 1 - 1.5 hours to grind a 180 mm blank to 80-90% of the final geometry (before HT). Of course - with more power and experience one could be a lot faster, but this is where I am with my 3rd blade ground with this little too.

1x30" belt grinder with Norton Blaze #60 belt

Vacuum cleaner

This is definitely not a 'must have' item, but an industrial vacuum cleaner will not only allow you to keep your shop clean, but you can attach it to some of the powered tools (e.g. some disc grinders, band saws, belt grinders, etc.) and that may keep the dust (in particular wood or other handle material) to get spread over the whole workshop. I have a small disc grinder and attaching a vacuum cleaner made huge difference.

Important to note here is that you do not want to use a normal household vacuum cleaner, as those will not survive long sucking fine dust and in particular metal dust. I finally chose Metabo 32 L and my first impressions are very positive.


Start grinding wood and you will really want one.

This is of course not an exclusive list. There are many more tools which you may or may not need (buffing wheel, dremel, etc.). Buffer will be something you want if you are making some hard wood handles for knives.  A dremel can help you with some detailed work around bolsters and help with many other smaller tasks.

Wednesday, June 22, 2016

The tools - part #1 - basic tools

There will be many tools that will find their way to your workshop. But you do not need them all at the start. Here I would like to first talk about those that you will need right from the start.

If you are just starting on considering it, you have surely seen a couple of videos on youtube that are meant for the beginner. There is lots of good stuff out there. I personally found videos from several knifemakers very helpful (see a short, non exclusive list below), but I found that usually far from all tools are mentioned.  Since I was really starting from scratch I realized that those little things add up to a considerable budget. For that reason here is a more comprehensive list of items with their use and necessity 'grade' - at least as I found them to be.

If you already have some sort of workshop with basic tool, than you may really need very little to start, but for guys like me - living in a flat with just a small basement with limited space, it does make sense to consider what it is that you need and how are you going to manage it.

Safety equipment.

Do NOT skip this just because it does not sound manly or relevant - especially if yo are new to this kind of stuff and have little experience in using tools or working in a shop. You really do not need much to avoid unnecessary injuries and exposure. You are basically going to need 3 things + some nice-to-have

  • Safety goggles (about 10€) will keep you eyes safe from little sharp objects (steel while cutting, sand paper grit, wooden splinter, etc.). I would not turn a belt or disc grinder without having these on.
  •  Respiratory mask with filters - something like the half mask from 3M (series 6000 or 7000) or even full face mask (which will give better eye protection). The mask is super important. I wear mine always when I cut, file or sand stuff. Be specially careful if you plan using G10 (read up on the topic). I would add that with half mask the safety google will not sit quite as well. I currently use half mask, but consider getting full mask for this reason.
  • Working glows. It may feel clunky wearing these, but they will keep your hands safe from trivial scratches and bruises (which will still take days to heal - in particular if your hands were dirty and/or oily) - you hand will often slip when cutting or filing. How eager you will be to wear the gloves will depend on the temperature in your shop, but my advice is - wear gloves every time you can. Unless you will need more precision, just keep them on. It will also help your hands not to look completely wasted at your day job.
  • Should you be working with heat sources (kiln, gas torch) or tools that throw sparks (grinder) than it may make sense to get a fire extinguisher - in particular if you are working next to pile of cardboard boxes like I do :)
  • Also - prepare a small first aid kit to be able to clean a wound and be able to stop bleeding - you need to be able to access it with one hand - as most of your injuries will be on your hands.
  • I have recently got a face cover - 3M G500 that also has ear protection and it is excellent. In particular when grinding or working with angle grinder it offers full face protection and can be worn with the half-mask rather comfortably.

Basic safety set - goggles,respirator (half mask) and gloves.


Recent addition - head cover G500 from 3M


Notebook (an analogue one)

For me - this is one of the most important tools. I keep a log on what, why and how have I done things. I note mistakes under 'lessons learned' tags and also ideas (mine or from someone else) that have helped me to improve something. I would make a sketch or drawing of what I plan to do. I can always browse through my notes, find out how much time I needed to finish something and later may try to optimize the process. It also gives me a bit of feel that I actually did something - in particular in the stage, when I do not have any of my projects finished, but several at works.

I recommend A4 size with hard cover, so that you have enough room for some drawings and so that the notebook survives the environment.

The workbench

There is no way around. Without a stable workbench you can not start to make knives, unless you want to recreate stone age conditions. When I started I quickly realized that a decent, stable workbench is not cheap. I tried to find a used one, but nothing was available at reasonable price locally, so I finally decided to buy a new one. I got one from Powertools (in Germany) and while far from perfect (I naively expected more for 250€ shipped), I made it near-perfect with some added stabilization bars. Apart from the size (mine is 150cm long, 60cm wide and 92 cm tall) - the most important number is height - you want something around 85 - 95 cm, so that you do not have to bend when standing next to it and working. You will find that most of the work (because of the effort involved) needs to be done while standing and not sitting, so a bench of 80 - 85 cm tall may prove not tall enough. Also - the bench should have a wooden top board. It will allow you to mount a vice or other tools (or, as in my case - properly mount the articulated lamps)

Sturdy workbench with wood top. Yes, this is tidy in my book :)


Vise

I got mine, rather subtly build wise with 10 cm wide jaws, before I decided to take on knifemaking and I was concerned about its robustness, but I was pleasantly surprised that it works pretty well - even with added rotation base. In general - I would go with 10 or 12 cm large (wide) jaws and rotation ability around vertical axis. Horizontal rotation is a nice-to-have. I have not really needed it yet, but have seen on youtube that there is a legitimate case for it. One more detail - because of space constraints I have mounted my vise on separate board that I attach on the workbench with large clamps, so I can remove it when I need more space. Remember - that 150 cm long workbench is all I have.

Even though on the subtle side, this 100 mm vise does its job well.
The rotating base is very useful.



Hack saw

Since my presumption is that you do not have (or can not) use some sort of powered saw (band saw for steel cost upwards from 300€) - you want to get a decent hack saw. These do not cost much. Try to get one that has good provision to tension the blade and to set the blade under an angle to the saw (you need that if your make long cuts and the blank you are just cutting out starts to get in the way). Mine was about 20€ (something I consider 'no name'). But the real point are the blades. Most probably the one that will come with the saw will be far from the best you can get. For metal you want 24 teeth per inch (they do well with wood as well), bi-metal blades. Do not waste money buying them by piece - get 10 of them and get the best you can. They really make a difference once you start cutting out a blade from a steel. With a good quality saw you will be able to cut a knife blank with 10 cm blade out of 3-4 mm thick piece of steel in less than 30 minutes.

The hammer shown has a round end excellent for peening. The heavy duty scissors is
most often used to cut sanding paper.

Files

You will need a few different files one way or another, but if you plan to file the bevels (free hand or with a jig), than you want the best files you can get. In my case these are Swiss DICK Precision files. I have several of them today, but the following ones would be the most relevant to start with (I am quoting the ID from the DICK web page for clarity for some cases):

  • 112300: 300 mm (12") flat file, Cut #1 (bastard in US naming convention). This is the main workhorse for the bevel grinding. I also used it to rough finish a blank after I was done with a hack saw. Consider 300 mm to be the minimal length, 350 mm would be even better.
  • A possible alternative to the bastard file would be a dreadnought file - it has curved teeth and should have less of a tendency to clog during filing. I did not try one yet though.
  • 200 - 250 mm flat file Cut #3 (medium cut file). I use this file mostly to smooth the edge of the blank out, or to work on ricasso shoulders for hidden tang knives.
  • 1166200: 200 mm round file with diameter of 7.8mm - this is about the right size to work around the choil area. The file gets thinner towards the tip which can be practical
  • 1156200 (or 1156250) Half round file in Cut #1. This file would allow you to contour the blank for a full tang knives. 
  • Set of needle files. The main purpose of these is to work on bolsters for hidden tang knives as getting a nice clean fit is what you are after. You will need to very thin flat files as you will be filing openings as small as 3x10 mm and the file must fit in that opening. You will also want a very thin needle file - see Project #1 and #2 for details.
My most used files. The 300 mm #1 file is not shown as it is mounted on the grinding setup.
The 3 large files are 1x 250 mm and 2x 200 mm.

Sanding paper

You will need sanding paper to sand non hardened (e.g. when flattening the steel before you start), hardened (removing scale after HT , finishing the blade) and wood (handle finishing). The metal sanding makes more sense with wet sanding paper as it allows to last longer and will give you smoother finish. I have started with Matador (black on blue backing) papers and while it is a nice paper, I found that it was looking grit grains what gave me some problems when finishing the blade. The I have learned about Rhynowet Redline sanding paper. The feedback from knifemakers was so positive, that I directly ordered 50 sheets in grits from 60 to 400. My first impressions are very positive and the paper even costs a little less than the Matador. Within my limited experience I do not hesitate to recommend this sanding paper.

My stock of Rhynowet sanding paper. I will be adding #600 and #1200 soon.

Drill 

You have basically 3 options. Manual drill, hand held drill and drill press. All 3 of them will get the job done. I have started with the hand held Li-ion drill I already had. Power was not the problem, but if you want to drill holes at well defined positions under well defined angles, than even a cheap drill press will make a huge difference.

It did not take me long to realize this and I got the Bosch PBD 40 and it is a very capable tool. There are cheaper options, but here in DE this particular one got very good feedback and I am happy with it.

Lightening

Easily overlooked, but you really want several strong light sources. In today's age you can get powerful LED bulbs. They are not cheap, but last long, consume little energy and, more importantly, do not get hot and thus do not want to grill you. I have in total about 40W of LED power divided in 3 lamps - one is on the ceiling and two are articulated lamps - one on each side of the workbench. I will get more sturdy lamps in the future (these were 10€ a piece and are meant for a writing table), but these do work, one just need to be careful with them. The most important feature is that they are articulated - I am able to get the light where I need it. On top of that I have a small lamp with a clamp - I often use this one 'free hand' to check for scratches when finish-sanding a blade (so that I can leave it clamped). Ideally I would like to get one more lamp from top-behind in the future.



Here you can see all 4 lamps.



There are many more tool you will sooner or later need. I will be posting a few more articles on this topic.

Saturday, June 18, 2016

Do not underestimate 1x30" belt grinders

If you have ground a few knives with a file or filing jig, than you already know how much work it is to first prepare the blank for grinding, grind the bevels and then grind the final edge once the knife is heat treated. In particular if you find out that you actually need to thin the blade after HT because you left it too thick before (ask me how I know - see Project #3 for details).

But you probably also already know that a good quality 2x72" belt grinder cost around $2000 (OK, you can get a simpler 2x72" like Grizzly for about $600 in US, but it Europe you are out of luck).

There are however ways in between and about the cheapest option there is is a 1x30" grinder. These seem all to look rather similar and may come with a small (125 mm diameter) integrated disc grinder and cost under $100/100€. The question is - are these any good? The short answer is ... YES

Still clean. The work rest for the disc grinder is not attached yet.
The grinder in question is marketed in Germany under the name Scheppach. The belt grinder has some limited possibility to center the belt (with a small knob on the rear wheel) and that is it. It is even possible to attach a vacuum cleaner hose on the bottom-left side (something that proved very useful alraedy). The exposed part is partially supported with a thin steel plate (barely visible in the photo above) and part is unsupported (slack belt). You can also remove the upped plastic cover and use the upper wheel for grinding curves.

Basic features

The 'platen' of the grinder is a relatively thin L-shaped (attached with 2 screws) piece of steel that flexes relatively a bit under pressure.  If you plan doing some more precise work you will probably want to replace it with something more stable, but  you will have to make it yourself. Still - the platen as it is is usable.

I would also like to mention the speed of the belt. On this machine it is around 13 m/s - that is pretty much spot on - in particular given the low power of the grinder. Important is, it is not super high speed grinder as with just 250W it would be way to easy to stall (which you can still do, but it can be avoided with a little experience)

The work rest on this particular grinder as made out of aluminium and is not particularly strong. It is attached on one side and it does not really allow to be set under an angle.


The 'platen' and the work rest.

The side cover of the belt grinder has an attachment point for a vacuum cleaner. Since I got the Metabo ASA 32 L industrial vacuum cleaner I use it all the time. barely any dust (steel or wood) gets away.

Side cover of the belt grinder.

The disc grinder has a bit more substantial work rest (though still made out of aluminium) that can be adjusted from 45 to 90 degrees. A plastic part can be attached that allows to attach a hose from a vacuum cleaner. This proved VERY efficient in minimising the amount of dust (in particular when grinding wood) that would spread across the workshop.


The translucent  cover of the top wheel can be removed and you can grind some curves around a handle.

From inside

Removing the belt cover you can see the bottom large wheel that transfers the power from the motor to the belt, the top wheel and finally the rear wheel which has an adjustment knob.



This adjustment knob has 2 functions (which would be adjustable separately on a more upscale grinder) It tensions the belt AND it allows for certain left/right adjustments.

Adjustment knob on the rear wheel.

How to set up

To attach and adjust a belt I found the following procedure to work the best:
  1. Remove the plastic cover and unscrew the adjustment knob completely.
  2. Put a belt on the bottom and back wheel - 1/2 of the width.  Hang the belt loosely on the screw next to the upper wheel.
  3. Press with your left hand of the rear wheel and push it against the spring (towards the platen). 
  4. Slide the belt on the upper wheel with your right hand.
  5. Gently push on the belt from the side to get it fill width on all 3 wheels.
  6. Screw the adjustment knob until you see the rear wheel moving (tensioning the belt)
  7. Turn on the grinder briefly and see how the belt runs. If it is too far left or right adjust the rear wheel. If it keeps jumping off the wheels on the left irrespectively how much you adjust the rear wheel, than you will need to use a little brute force and push on the frame close to the upper wheel towards the right. I did have to do that. This will affect the belt alignment agains the platen, but it will run well without jumping off the wheels. 
  8. Repeat the step 7 gently until you get the belt running stably with the adjustment know around the middle of its range.




Preparing to mount a belt.

Pushing on the rear wheel (once the adjustment knob has been screwed  loose).








Disc grinder side with the vacuum hose attached.
That big green thing in the background is the Metabo vacuum cleaner :)




Belts

The grinder comes with some sort of cheap aluminum oxide belt which will not last much when working with steel. To grind steel you will need to get belts that were designed for such purpose. In general this means to get Zirconia (also called ceramic) belts of some sorts. In Germany there are Klingspor belts available, I have got a few for testing, but I have not been too impressed (part of the reason was the grit - 24 is way too coarse and breaks off the belt easily).

Some really nice belts: from left ro right: 3M Trizat 'gator', Sait 7S #80, Norton Blaze #60 , Sait 7S #240

You basically need (want) 2 types of belts for the start (that is what I have at the moment)

  • Ceramic belts (like Norton Blaze or Sait 7S) for bevel grinding or handle shaping. These belts are relatively hard and last a long time
  • Softer belts (3M Trizact - 'gator' or 'normal' - these are available in higer grits and are great for removig scratches, or getting around the corners of a handle or a knife heel on a slack part of the belt.

I have also briefly tested Sait 7S and Norton Blaze belts. I have used Sait 7S in 40 grit to profile a blank (after rough cutting with angle grinder) and I have finished 6 blanks with single belt and the belt will do a couple more.

Norton Blaze in 60 grit seem to be the right fit for this grinder - they cat plenty fast (remember - this baby has only 1/3 hp) and seems to last well.

So - what can you do with this baby grinder?
  • Profile blanks - this is so much faster than with a file AND i allows you to use a quick and dirty method of cutting your blanks with an angle grinder (the cheapest 'powered way' to do so).
  • Grind bevels - there is quite some learning curve - the narrow belt does not make it easy to get even grind and the platen is not quite as sturdy, but it can be done - and it is of course faster than with a file.
  • Final-grind bevels after heat treatment (care needs to be taken not to overheat the edge)
  • Shape handles - you can use the slack belt part for easier rounding of the blades and the upper wheel for some radius grinding
  • Shape bolsters
  • Shape your hand-made fixtures and tools (i.e. to take off edges of a file if necessary)
  • The little sanding wheel can be used (with some experience) to flatten/square blade steel and handle blocks. You would want larger disc sander for that, but hey, once it is there why not giving it a try.

Weak points

Not evetything is perfect though. With these simple machines you will have hard time to square things up, the 'platen' is rather weak and will flex under too much pressure making keeping constant angle harder. And, obviously, the narrow belt will make it harder to get even grind. But none of these little deficiencies is a show stopper. You have also very limited possibility to set the tension and position of the belt on the grinder.

A few examples

Grinding a bevel on a blade.


Grinding the glued WA handle to rectangular shape.

Flattening the sides of the handle with the disc grinder before final shaping.
Final shaping of the handle with the disc grinder.
Grinding to shape of integral handles (here birch bark handle).

General warning

When using the disc grinder (this one or bigger model) - be careful - if you do not hold the item you are working on firmly and the grinder bites into it (dents it in the process), it will send it flying across your workshop. Happened to me a few times with the WA handle shown above. So be careful and wear your safety gear.

Dust

If you start using the grinder (and in particular the disc grinder) to grind wood, you will find out that it will produce crazy amount of fine wood dust that will get everywhere. I finally broke down and got and industrial vacuum cleaner (Metabo ASA 32 L) which can be attached to simple plastic covers and can directly suck-away good 95% of the dust produced.

In General - steel dust is rather heavy and does not tend to spread quite as much as wooden dust. In particular the disc grinder will tend to fan the fine wooden dust over quite a distance, so using some sort of suction device really helps.

The costs

Let's be honest here - the cost of this little grinder itself will sooner than later be topped by the cost of the grinding belts. Remember - the worse/slower the belt cuts, the faster will the blade heat up as the hot material that is directly in contact with the belt is not being removed and all the work the grinder does is being turned to heat.

You should expect to pay around 2 $/€ per good quality ceramic grinding belt and  more for those awesome 3M Trizact "gator" belts. And you want them.

The vacuum cost me around 150€ (but it also helps to keep the workshop in shape). There are cheaper models for under 100 € that will do the same job.

Summary

The take-aways are:
  • This is a little capable machine that will alow you to get decent results and to learn how to use a belt grinder.
  • When grinding handle material you may need a vacuum that will keep the dust in check
  • Be careful with the disc grinder - it likes to send stuff flying around.
  • Get high quality ceramic belts for steel grinding (like Norton Blaze or Sait 7S). Cheap aluminium oxide will last just a fraction of a ceramic belt and is not cost effective.
  • The cost of the grinder will be quickly topped by the cost of the belts




Please do not hesitate to ask questions or share your views or ideas :)