Sunday, December 18, 2016

The Dreaded Bevel Angle Calculation

Online Knife Bevel Angle Calculator

It's been super cold the past two weeks and I haven't had a lot of quality time in the sub-zero garage working on knives. I have to keep busy, and warm, so I've been working inside on a tool that lets us set the bevel angle on a blade by the grind height and thickness.

To work this out we need to look at the thickness of the steel and the height of the grind and make a simple right triangle.

Here our steel is laying on the flat. Imagine we want bevels that look like 'A'.

Adding a horizontal center line will divide the steel in half.

Adding a vertical line at the grind stop will allow us to extract a right triangle. Voila! High School was finally useful!


In order to get from a right triangle to real world grinding angle, we need to assign the Adjacent (A) and opposite (O) values.


There is a mnemonic used to remember which trigonometric function to use when we need to find some missing part of a right triangle. This mnemonic is SOH CAH TOA. Okay... what the?

SOH CAH TOA helps us remember to use the Sine function when we know the Opposite and Hypotenuse, we use the Cosine when we know the Adjacent and the Hypotenuse and we use the Tangent when we know the Opposite and Adjacent values.

In our example for blade grinding we us TOA or Tangent for Opposite divide by Adjacent.

Let's put some real numbers in. Say our knife is going to be a hefty 0.25" thick. We take 1/2 of that to make the right triangle, so O is 0.125".  We'd like a grind height of 3/4" or 0.75".

Using the ATAN function on our calculator we can determine the angle in radians. But, radians is not degrees. We need to multiply radians by 180/pi to get the degrees.

Here's the link  for Imperial and this link is for the Metric Grind Angle Calculator.

I promise no more math for the rest of the year.

Merry Christmas,


Thursday, November 10, 2016

2x72 Grinder Wheel Set

2x72 Grinder Wheel Set

I am building another low-cost 2x72" grinder and I am super fortunate to have made a friend at Oregon Blade Maker.

Marinus at Oregon Blade Maker is offering some high performance, yet light-weight and durable grinder wheels for a low cost 2x72" DIY build.

These wheels are computer engineered, glass-filled nylon (durable composite plastic) with 1616RS bearings.

The wheels in this set are two 2-1/4" wide x 2" and one larger diameter crowned 2-1/4" wide x 3" which is designed to assist in belt tracking.

The wheels will mount with any 1/2" bolt. Plan for three 1/2" NC x 3" to 3-1/2" grade 8 bolts and suitable nylon lock nuts and washers.

These are low drag and spin freely.

Of course, the OBM glass-filled nylon wheels are not going to take over the aluminium premier wheel's top spot in roller Olympics, but these OBM nylon wheels offer value that cannot be denied.


November 10, 2016.

Tuesday, October 18, 2016


This is the first of the Christmas knives. A 150 mm Honesuki style with a western handle. It's made from AEB-L 0.130".

After shaping and some cleaning, I make a wire hanger and dip the blade in the stop-off paint.

The temperature of the furnace is targeted at 1060°C (1940 F).

Out of the fire and into the oil.

Although AEB-L is an air hardened steel, oil seems to result in a slightly harder steel. After hardening, it's tempering time. 185°C for two periods of two hours each.

Unlike some honesuki that have a left or right handed grind, this one will be symmetrical by request. I work each side with 60 grit ceramic belt cooling with water every pass or two. Once the primary bevels are close to 0.020", I move to a 120 grit ceramic belt.
This is a result of about 1 hour of grinding and polishing. For polishing I like the fine and very find conditioning belts, like Scotch-brite or Vortex. The "grain" runs longways. I feel that looks the best.

With the blade polished, the marks etched and cleaned with windex, the blade gets taped right up to the shoulder. Then the pieces of the handle stack get fitted. The most critical is the first piece as it has to fit well with no major gaps. For this I like to use a 3/32" bit and a flat needle file.

The block is desert ironwood. Here I am fitting and tracing the tang and screw against the block. This will give me an idea where the drilling needs to occur.

Once the pieces of the stack are complete and dry fitted, the epoxy comes out.

In this case, I am applying a small amount of pressure to keep the blade and handle in a straight line. I leave the clamp on for 12 hours.

After about 24 hours, the handle is ugly as hell, but ready to start shaping. The flat faces are ground first.

Then the rounding of the handle begins.
As the rounding gets closer to the finished shape, I like to run on the slack belt and rotate the handle to give is a nice uniform shape. A 60 grit belt is followed by a 120, then a 220, then a 400 and lastly a 600 grit aluminum oxide.

Then it is over to the buffing wheel. I used black compound then green compound. The ironwood is naturally very oily.
Here are some pictures of how the knife turned out. 

After taking the masking tape off and cleaning the blade with acetone to remove and extra epoxy and fingerprints etc.

Thanks for stopping by!


Monday, October 17, 2016

Posting Comments

Comments are Actively Being Reviewed

Hi and thanks for visiting.

Due to the large amount of spam and off topic comments that are being posted, I wanted to let everyone know that I will be screening all comments before they are published. I realize this is a pain for some, as it  may take a little while for comments to appear. Please be patient. I have a real job and family and due to wide time differences around the globe it may take some time to get to reviewing your comments

A large number of comments are appreciated. I am specifically deleting comments those that are off topic and just spam links. This filtering keeps the comments useful to you the readers.

As you may know, I am more than happy to answer questions that you may have.

Thanks for your understanding!

Happy making,


Sunday, October 9, 2016


This is the sister of the first DH54 that I made for the Knife in the Hat K.I.T.H back in the summer of this year. The blades were prepared and heat treated at the same time, so only the bevel grinding and handle fitment was needed to bring this one together.

The profiled  shape has a pronounced finger choil.

Holes are drilled for the pins as well as some additional holes to reduce the handle weight.

I am practising the motion for grinding the bevels. I want a flat grind with a distal taper from the front of the handle to the tip of the blade.
As the grinding progresses, I am dunking the blade in water every pass or two to keep it cool. Working each side over and over to create and nice flat, tapered grind.
After the bevels are close, around 0.02", I do the hand sanding on the bench.
Followed by some passes on the conditioning belts.
The edge before applying the cutting edge is around 0.018". This will make for a very fine slicing edge.

For handle material I have chosen Acrylester Abalone, a synthetic product popular with pen turners. It should buff up and look like a polished stone.

Two pieces of black fibre spacer make for nice contrast in the handle. After drilling out the scales, I have pinned it here with wooden dowel.

Some last minute finish on the blade with 600 grit sandpaper. From here on it's got masking tape on the blade to protect it when the handle is shaped.
With the temporary pins in, I can true and polish the scale fronts.
The pins are 1/8" mosaic, 3/16" mosaic and a 1/4" brass tube for the lanyard hole.
Pieces are cleaned with acetone and prepared for glue up with West System's G/flex epoxy.
I like to see the epoxy around the pins.
Clamping around 10 lbs. Clamps are placed at various locations to ensure a nice even compression.
After waiting a day and taking the clamps off this knife (as all the others do) looks like a horrible mess. But that is about to change.
Over to the grinder to make the faces. Acrylester plugs up belts like crazy, so I am finishing off an old 60 grit for this step.
Once the faces are trued, the shaping proper can being. I did this with a 60 grit and then 120 grit belt.
I did some wet sanding on the bench and the Acrylester really starts to pop at around 400 grit.
The 1" drum sander attachment on the drill press comes in handy for the finger choil.
The handle is shaped in a slight "coke bottle" shape when viewed from the underside.
Some buffing on a clean cotton wheel makes the Acrylester shine like glass. Care needs to be taken not to melt the material here.

Here's a shot from the light box with the sheath made.