Sunday, May 29, 2016

Bevel grinding jig by Aaron Gough

When I started toying with the idea of knife making I was mostly put off by the fact that one needs a belt grinder (or so I thought at that time) to be able to grind the bevels and I had neither the workshop space, nor did I want to spend 1500€+ on one. This changed when I have accidentally came across the video from Aaron in which he describes in detail how to make a beveling jig using only very simple tools and materials - at that point I decided to give it a try - thank you Aaron! :)

I am not going to copy in words what Aaron describes very well in his video, I would only add my experience and some slight adjustments I did to the basic design. So before you read on, please watch the original video:

From my point of view the main properties of this jig are the following:

  • Faster than a free hand filing. Takes about an hour per side on a 10 cm long outdoor knife blade
  • Fast learning curve
  • Easy to get very consistently ground bevels and plunge lines - much easier than when you start learning how to use a belt grinder or free-hand filing.
  • You can create flat or convex grinds
  • Once you get to kitchen knives you need to get more careful about the grinding angles (as these will be as low as 1°)
  • Also - with those low grinding angles (and large contact area while grinding) the file will have a tendency to skate on the blade (it is NOT dull, do not have yourself fooled)
  • Long thing blades of kitchen knife will tend to flex under pressure while grinding and thus changing the grinding angle.
  • Obviously slower than a belt grinder
  • Does not work on hardened blades/steel (the files usually have hardness around HRC 64 - 66 - that is too close to the hardness of the blade, so you would just dull the files without removing much material.

My changes to the original design from Aaron

Aaron pretty much nailed the design. I found that the steel rod that serves as a guide was producing rather loud and unpleasant noise as it was riding in the steel bolt, so I have replaced the bolt with a 10mm thick PVC board with a hole attached to a piece of wood on 2 threaded rods for height adjustment. Now this part of the jig is completely silent.

I have also added a second raw of mounting holes for working on smaller blades and to avoid grinding into the wood when getting closer to the tip.

A small update was adding a 4mm thick rubber ring to the bottom clamp to protect the blade from damage when accidentally bumping to it with the clamp. A simple, but effective solution.

How to grind kitchen knives with this jig

The main difference between kitchen and outdoor knives:

  • Longer AND thinner blade
  • Much more acute grind
  • A simple full flat grind will not make for a great  kitchen knife  - you want either a wide-bevel grind or a convex grind of some sorts
  • Kitchen knives have pronounced distal taper from the handle towards the tip.
The above means - you will be working on a large blade that in non hardened state is not all that stiff. To grind the convex grind will take some basic math to thin of in advance and calculate the angles (and thus the height setting of the bolt) to make.

Before you start grinding make sure you have the centre line (or two lines close to centre that mark how thick the blade should be once it is ground) scribed onto the cutting edge. It is also a good idea to scribe a centre line on the spine so that you can grind the distal taper symmetrically.

Once you have the design and in particular the grind (geometric cross section) on paper - start to work your way down and draw straight lines how you want to get there with the grinding jig. In general you want to start from the edge (with the steepest grinding angle) and work your way towards the spine of the knife in subsequent steps. After each step you want to remove the knife from the holder and measure the blade thickness at few positions (and different distances from the cutting edge) to see whether the grind follows what you have intended. Remember - you can always remove metal if needed, but not put it back on the blade. So proceed carefully. Important is - before you start with the first grind measure the thickness of the blade carefully and calculate how thick the edge should be once you are finished with the first grind.

Starting with first grind on 240 mm gyuto blade

Little tip: In the photo above note the brass screw used as a stop-pin (to keep the blade from moving). Kitchen knife blades are ground pretty thin towards the tip and thinner than any flat heat screw is. Using brass screw (softer than the steel) would mean that as your grind gets thin the screw will be also ground thinner and will not disturb the process. After that you have a nice flat stop-pin screw :)

In the knife shown below I have approximated the convex grind with 3 planes. You start with the one closest to the edge. Remember that you do not want to grind the edge to 0 thickness prior to HT - you want the edge to have some thickness (say 0.3mm) so that it does not crack or warp in the quench. The grind 2 and 3 are made under smaller angles, but you do not grind down to the edge, but stop a certain distance from the edge. I stopped 5 mm from the edge with the second grind and 10 mm from the edge with the 3rd grind. You can blend these multiple grinds afterward with cross-drawing a file (more on that below).

First grind nearly finished

Before changing the grinding angle re-paint the already ground part of the blade and scribe (or paint) in the distance from the edge where you want stop with subsequent grinding.

3rd grinding step - here I am stopping cca 10mm from the edge

You want to switch sides after each step and ideally a few times during the first grind as this is the one step in which you remove most of the material. The reason is as you grind higher up the blade you start to loose support area (once you switch to the other side). While you can not avoid that, with regular swapping you can minimize the effect of possible asymmetry while grinding. 

Once you are done with the grinding jig you move to free-hand grinding. You get one or two steps finer file (the Cut #1 would leave crazy deep scratches) - I am using Cut #2.  Holding the file on both ends with you hands you get very good control. If you have you edge at the final, pre-HT thickness and do not want to grind it down, than mark the edge with a permanent marker.
Cross-draw 'jig'. Note the small clamp in front of the tip that serves as a tip protector.

My cross-drawing 'jig' is just a piece of wood slightly shaped as the blade so that the blade, so the wood will not get in the way. Important - make sure the cutting edge is not sticking outside the wooden support - you risk cutting yourself and/or damaging the cutting edge (which at this stage is weak and easy to dent). I also use a simple clamp some 5-10 mm from the tip that stops the file from sliding off the tip. The reason is - you work with quite some force and if you slip off the blade you will most probably not manage to stop the next stroke and will hit the blade tip with a file and badly bend it (beyond repair). My first blade lost about 5 mm on the tip for this very reason.

You can speed the this process by slightly tilting the file and using the edge of the file. This will make the file bite much more aggressively into the steel, but it will leave deep scratches. Removing them with files and sanding paper will yield some additional material removal and if you do not take that into account you will loose some blade height - that is what happened to me with this very knife.

Deep scratches after cross-drawing with edge of the file. These are deeper than they may appear.

The solution is - stop some 0.3 mm from the desired blade thickness (geometry) and proceed with using the whole contact surface of the file and once you have removed all the deep scratches then  proceed to about grit 60 wet sanding paper (I use WD-40 as lubricant). Clean the blade (remove scratches) up to about grit 240 (i.e. 60, 80, 120, 180, 240) before going for HT. It minimizes the chance of micro-fractures during the quench and will also make your life easier finishing the blade after HT (since the blade will be much harder then).

After HT the knife will be too hard to work with files. If you have left the knife too thick further up from the edge you will need the most aggressive material that allows you to remove metal - for me it was Atoma 140 diamond plate. If you did the pre-HT grinding right, than you only need to work on the first 5 mm behind the edge - that should be doable on coarse sharpening stones. You can also use a diamond plate, but I would not go with one as coarse as 140, because you may 'overshoot' if you do not account for removing the scratches in subsequent steps (which is also material removal). Atoma 400 would probably be a better idea. I plan to stick to water stones if everything goes according to plan and starting with either Bester 220 or JNS 300.

So, this is what I have to say to using this grinding jig including some subsequent steps. Remember - this in only one possibly way - do not hesitate to come up with your own approach. And of course - have fun :)

Last but not least - thank you Aaron for sharing this simple, but very effective grinding jig!

Saturday, May 28, 2016

Before you start

OK, so you want to make your first knife. Before plunging (and possibly getting lost) into the details, I think it make sense to have a look what steps need to be done to get the idea to the finished knife before you go out and get first tools or materials.

Here I just want to mention what I found was relevant to think about, I will post separate articles on each of the steps later. My main point here is to start the thinking and planning process. I was not as thorough and it would have made sense to consider some possible issues or limitations in advance.


Have a look at the space you have available. It may be a well equipped mechanical shop of some kind, it may be your garage, but also just a basement or even a room inside your house or flat. You do not need a whole lot of space. I have set up a workshop in part of our basement with a area of about 2x2m. More would be nice, but it can be done.

The questions you should ask yourself are:
  • Is it OK to produce and and noise there (always keep your neighbours in mind). Most of what you will be doing is either loud, dirty, or both
  • Is power provided (at first just for illumination and maybe for a drill)
  • If you plan on that - could you be doing your own heat treat there?
  • How is the ventilation? If limited, you may want to do the 'smelly part' (gluing, degreasing, oiling handles, etc.) elsewhere.
  • General safety (what are the local rules and what are sensible do's and dont's)


You will need quite a few tools and I will try to summarize on that, but the basic ones are:
  • Sturdy working bench
  • Means to keep and organize your tools (you can not have them all on the working bench)
  • A vise
  • Hack saw + bi-metal blades
  • Files
  • Wet sanding paper in grit 60 - 400
  • Flat surface for sanding (stone block or a tile)
  • Clamps (different sizes and shapes)
  • A drill (ideally a drill press + a small vise) + drill bits (HSS-Cobalt)
  • Epoxy
  • Some kind of wood finish oil - Tung oil seems a good choice
  • Metal ruler and calliper are a great help
  • Notobook, pencil, permanent marker (a thin and a wide one)
  • some more stuff :)
Knife design

You do not need to have a complete and in detail though-out design, but having a rough idea where you want to start helps to plan what tools you will need and it also helps you to estimate the budget. I have in mind basic features like:

  • Type of knife (shape and size of the blade)
  • Full tang or hidden tang
  • Handle materials (bolsters, scales or block, pins)
  • Sheath or no sheath


Depending where you live the availability and price of materials necessary for knifemaking will differ greatly. Do some research for knife making supplies, in particular for:
  • steel (thickness of 3-4 mm and width of about 35-40 mm would about right for an outdoor knife)
  • handle making (wood, pins, bolsters)
  • sheath tooling (leather, tools)

Developments in (mainly stainless) steels in the past years have give rise to steels that on knife fora are often designated as 'super' steels and there are endless discussions whether steel X is better than steel Y. First of all - there is no perfect steel - different steels will perform better at some tasks and worse at others. Today's 'super steels' are complex, high alloy steels that not only are expensive, these are also often very wear resistent (read - super hard to grind) and require complex heat treatment. My advice is - stay away from those. I am talking about steels like S35VN, Elmax, M390, HAP-40, S110V and similar.

I would actually suggest that you stay with simple carbon steels like 1075, 1084, 1095, O1, W2, 52100 or if that is your preference - simple stainless steels like 440C, AEB-L or Niolox. Not only are these considerably cheaper, they are easier to HT (see below for more) and easier to grind and also easier to sharpen. Still - with a proper HT you are going to get a knife that will match outperform (in particular the carbon steels) in certain regards the much more expensive super steels.

Heat treatment

There are many videos on youtube how you can do the HT with very simple tools. Simple carbon steels (for example 1075, 1084, O1) are relatively forgiving when it comes to the temperatures and thus you do not need a kiln with precise temperature control.

But if your location does not allow (or you simply do not want to start with you own HT), than do check for services online. Again - depending on where you live the options for outsourcing HT will vary. For example - if you only find HT services for stainless steels, it would make no sense to start making knives from carbon steel and the other way round. So check your steel choices against the available HT services before you buy steel for knifemaking.

Monday, May 23, 2016

Introduction & Motivation

Hello everyone,

 I guess a short introduction is in place - in particular to avoid false hopes that this blog is being written ab an experienced knife maker that is now going to share his hard earned experience. Wrong :) I am standing at the very beginning of a knife making journey and though that it could be of interest of other to share 'live' the first steps, decisions & mistakes.

Who am I

Since our existing experience and daily life has a great influence on how we approach new problems I would give you a brief view of who I am. I was born and raised in Slovakia where I studied nuclear physic. Together with my then-girlfriend we came to Germany for a PhD (both in physics). Being a PhD student at GSI in Darmstadt was a great experience and I met some extraordinary people - many of whom I feel honoured to be able to call my friends. Once accomplished we moved north for a post-doc position and once that one approached to its end 3 years later we started to look for a job in industry and finally ended up as developers in lithography optics and that is what we both do as of 2016. For me it means in-front-of computer job.

For a long time analogue photography was for me the escape and creative realisation, but once our little girl was born the time became more constraint and I had to reduce those activities a lot. In the mean time I became interested in Japanese kitchen knives and free hand sharpening. But there was a growing need for a more creative manual work and in early 2016 that just bursted in a knifemaking.

Where I stand

As of march 2016 I have a tiny (just under 4m2) workshop with most tools that are necessary to make simple knives.  The only power tools I plan to use is a drill press - the rest is manual or manual jigs (more about that in future posts).

 I have made 3 blades and I am just starting to make a first handle. I hope there is much more to come - I am eager to learn and try new things. I do not expect to get beyond hobby, but I would like to be able to make a usable outdoor and kitchen knives, even if some technique is going to remain out of my reach. It would be an accomplishment should I ever get as far as being able to sell a knife here and then, but from current perspective that is just a day dreaming.

Please note

You may have noted already - I am not a man of few words. So of you have any questions or comments - please do not hesitate to share or ask. I will try to help if I can.

If you are a knife maker yourself and find I have miss represented some information I would be most thankful for a correction. After all - I am just learning the craft.

If you have particular topic or questions you would like to hear covered or answered - just go ahead and ask. I will do my best.

So - enough of the introduction - let's get started :)