Thread: Heat treat before or after?

Thinking at try'n my hand at making a razor.
I was thinking it would be better to heat treat and temper before grinding to shape to keep the blade from warping from the harding process.
What is some of you alls opinions on when to harden and temper?
Before or after shaping the blade.

I would imagine grinding to shape first and keeping the edge thick enough to avoid damage, then heat treating, then finish grinding the edge. If anything grinding slow and cool will prevent messing with the temper.

I have been pondering this same question myself. I think the answer will depend on your equipment.

If you are heat treating with molten salts (like Tim Zowada), you may well be able to grind it to a nearly finished shape before heat treating.

Grinding first might also work with stainless steel, if you are having it professionally heat treated (say, by Paul Bos). With CPM154 CM or ATS-34, you could also have it heat treated first and specify the higher tempering temperature (800-1100 degrees F -for CPM154 CM), which would give you more wiggle room if you heat the blade more than you'd like while grinding.

If you are heat treating your own carbon steel in a forge or oven, I think you'll have to leave it thick and grind it very carefully after it's heat treated. A variable speed grinder would be quite helpful for this task.

For the moment, I'm holding off on making my own razors until I get my equipment squared away. I have the stuff to assemble a salt bath system, but haven't had the time to put it together yet. I'd also like to convert my Bader B3 to variable speed and get a smaller wheel for it. However, I might give the CPM154 CM a shot in the mean time.

I have been rough grinding/filing the blade then heat treating, followed by the final grinding.

It is easy to overheat the blade during the final grinding process. I wish I did not know this so well.

Charlie

Originally Posted by thewap

I would imagine grinding to shape first and keeping the edge thick enough to avoid damage, then heat treating, then finish grinding the edge. If anything grinding slow and cool will prevent messing with the temper.

What he said.

Thanks guys!
I think I'm going to try the heat treating then grind method .

Lets assume that you start with a 1/4" thick piece of steel.
1. Anneal the steel so that its soft and workable.
2. Cut the rough shape then grind the profile to a final shape. Do not get the steel hot.
3. Rough grind in the hollow grind of the blade and leave the edge 1/32" -1/16" thick.
4. Taper the tang
5.Polish the spine and tang to desired level of finish.
6. Heat treat and temper
7. Finish hollow grinding the blade and then polish it.

Just my $.02

Originally Posted by randydance062449

Lets assume that you start with a 1/4" thick piece of steel.
1. Anneal the steel so that its soft and workable.
2. Cut the rough shape then grind the profile to a final shape. Do not get the steel hot.
3. Rough grind in the hollow grind of the blade and leave the edge 1/32" -1/16" thick.
4. Taper the tang
5.Polish the spine and tang to desired level of finish.
6. Heat treat and temper
7. Finish hollow grinding the blade and then polish it.

Just my $.02

These are the steps that I have been using lately with one additon. At step 7 I really gouge the balde and return to step one with a new metal.

AARRGG!!!

Charlie

Originally Posted by spazola

These are the steps that I have been using lately with one additon. At step 7 I really gouge the balde and return to step one with a new metal.

AARRGG!!!

Charlie

Let's hear it for HONESTY