Thread: First Straight Razor Build (A learning Process)

Originally Posted by Bruno

And stay away from 52100 if you don't HAVE to use it for razors. Yes, it's good steel, and can stand a lot of abuse. But for a straight razor, those qualities are not needed, and will make it a lot harder to hollow grind the blade.

Thanks, that one is off the list then. I think that ATS-34 is off the list as well (at least for now). I don't need stainless.

Originally Posted by Bruno

EDIT: Copied from an earlier post of mine, in a similar thread about making a razor.


You want to taper the handle as well. Under no circumstances should you have a tang /handle that is
exactly as wide as the spine.
Once you start honing, the spine will get thinner. Not by a lot, but still. When this happens, you still want the blade to be perfectly flat on the hone. For this to happen, the tang / handle should never touch the hone, or you will get a sloping transition where the spine (and thus the edge) will always 'wobble'.

With knives you often see a small notch between the edge and the bolsters. this is for the same reasons: to make sure that the beginning of the edge will always touch the stone properly.

Also the following things:

- you don't want the tang to end in perfectly sharp corners, because you will scratch up a lot of things in the bathroom. the only sharp thing should be the edge
- get used to measuring things in empirical units. As much as I live in a metric country anduse the metric system for everything, the razor world operates in units of 1/16 inch for measuring the width and thickness of a razor. For lengths it's inches. Everything will go a lot smoother if you measure width in 1/8 or 1/16.
- carbon steel is perfectly fine for a razor. No need to consider it 'making do'. A razor is not subject to stress, fatigue, etc. The only thing that matters is the ability to take an edge and be relatively easy to hone. high carbon tool steel is a perfect steel for a razor. If anything, the challenge is to achieve the same level of edge quality with stainless, not the other way around.
- for the thickness you want to aim between 1/4 to 1/3 for the thickness vs width ratio. do not go smaller because your razors will be difficult to hold and lose its edge relatively quickly. In your case for 22 mm of width (~7/8") you want a stock thickness of close to 1/4"
- Leave the edge 1/16 before heat treatment, and grind away the rest of the hollow after quench and tempering.
- You need to grind the hollow so close that during honing, the bevels are uniform, and very thin. Ideally, the bevels should be a very thin, almost invisible line. A wide and uneven bevel is the sign of sloppy workmanship, and often indicates that only minimal post HT ginding was done.

That's a lot of good info to digest. Let me read this over a few times and stew on it. Thanks again!

Originally Posted by DVW

I wondered about this, but don't understand the relationship. The below sketch is not to scale, but what does spine thickness have to do with edge angle?

Attachment 168727

Because a razor always, Always ALWAYS is honed with the spine on the stone.
Did I say always? I meant ALWAYS

The only way to develop a razor edge is with the spine on the stone so that you always get the right angle. Freehanding or something else just doesn't work. A razors edge is measured in micrometers and that is only possible if the spine is on the stone, and the spine with is between 1/3 and 1/4 of the width.

I think that I understand now. The ratio between the width of the blade and the thickness of the spine act as a "built-in" angle guide for honing. Again the sketch is not to scale, but this is how I am understanding this. Thanks. I will start off with 1/4 inch thick steel.

Since nobody has made any other comments about the shape or size of the blade, then I am assuming that it is decent as long as I use ¼ inch thick steel. So I picked up some Basswood at the local hobby store and made a pattern to trace onto the steel. Mike Blue had some great advice on the type of steel to use. Since I have some old car springs (5160) laying around, that is what it will be made out of. Mike assures me that, if I do my part correctly, the steel will perform well as a razor. I haven't done any forging in about 20 years as I have been buying flat bar. My “current” forge is not completed so I guess that I will just have to make due.

Recycling old springs is a fun way to make knives... (or straights I would imagine I haven't made one) but as cheap as you can get a price of steel to build a razor out if I think I would just buy a little chunk and start from there. The problem with old springs is you sometimes have little stress fractures in the steel which can cause your steel to fail during the heat treat. I guess you would only be out your time if you have some springs laying around.... but sometimes having to start over can get discouraging. Just a thought.

Looks like you're getting some good advice on blade geometry and steel choice, so hopefully your first will turn out nicely! I recently made my first razor and the bevel on the edge ended up being a bit on the large side. As you're doing final grinding set the bevel on a course stone to see any uneven or wide spots on the bevel and try to zap those puppies out on the grinder. Should help get a small and uniform edge.

Spring steel is good. And you're right about the built in honing angle. That is the reason for the spine / width ratio.
Be sure to drill the hole before heat treatment. And if you're unsure about the length of the tagn etc, make a carboard cutout of your design and hold it between your fingers to see if the design works for you.

So I dug around in my scrap bin and found a piece of a leaf spring from about 20 years ago that is a bit over 1/4 inch thick. Also, I found a piece of O1 that I had forgotten about (bonus!). It is thinner than 1/4 inch but still pretty thick. When I get a chance I will put a set of calipers on it to see what it really is. Here is the piece of leaf spring.



After a few minutes with an angle grinder and a cut-off wheel I was able to come up with four blanks

Next was to flatten them (take the curve out) and anneal them. I needed a heat source. So after about half an hour of searching around the shop, this is what I came up with. It is crude but worked.



I took an old bar-b-q and gutted it. Then I drilled some 1/8 inch holes in a steel plate, welded a pipe to it and screwed it to the bottom of the bar-b-q. A shop-vac provides the air. Flame is controlled by detaching the hose from the shop-vac and just slightly "feeding" the air from the discharge of the shop-vac into the the end of the hose. Something better will have to be worked out before it's time to heat treat. I had a hard time minding the air hose, the fire and the steel all at the same time.

After I flattened them out, I placed them in a bucket of sand for slow cooling. Below are the blanks all flattened out and one of them is flat ground.



After tracing my Basswood template with a scribe I rough profiled the blank and drilled the hole. I had forgotten how pleasant this was to work with. It is so easy to grind and drill as compared to the high chrome steels.