Thread: TI Le Dandy honing headache

To add to what Euclid440 has said you should be able to use some basic math to work out how wide the spine needs to be to set an angle.

If you know trigonometry this will help.

If you don't there are numerous calculators online to work out right angled triangles.

If you go this route you have to remember some basic rules in converting to a razor from right angled triangles.

First to make a razor into a RAT you have to theoretically split the razor in half. So you use a single RAT per razor side.

You already have the blade depth, but working in inches requires decimalised inches. This is harder than working in metric.


The basic route would be to measure the blade spine to edge. So if your razor is a perfect 5/8 then your metric value is 15.8mm.

You already know the angle you want for the bevel 18 degrees. You have to half this as you are splitting the blade into 2 triangles. So 18 becomes 9 degrees.

Here is a RAT calculator.


Right-Angled Triangle Calculator

Your Side b is 15.8
Your Angle A is 9

Therefore Side a (the spine) needs to be 2.5mm per triangle. Your using 2 triangles so the total spine width should be 5mm.


Now you know what sort of ball park figure the spine should be at to get a good angle you can test various materials to try build the spine using spine clips, tube, or sleeves to get into the correct bevel setting region.


The math also works backwards. So if you build the spine to 5.5mm you can plug that back into the calculator.

Spine = 5.5mm so, edge a = 2.75mm
blade width = 5/8 = 15.8mm

Therefore Angle A = 9.87 Multiplied by 2 for each razor side = 19.74 degrees.

A bigger angle = less bevel.

I think most razors are 17-22 degrees total bevel angle. 22 will be a smaller bevel than 17, I would aim for 18-19 degrees to be on the safe side.

The smaller the razor the more pronounced a change in spine width will change the bevel.

A 3/8 razor will change it's bevel angle with far less spine wear than an 8/8 razor will.