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I'm making a pair of razors from 0-1 I've roughed the hollows down to where the blade at the cutting edge is about .050" thick. Should I stop? Should I go thinner? How thin is too thin? I'm worried about heat treating & warpage. Even though I'm taking blanks to a professional heat treater that surely wont promise flatness. And with the ease of metal removal while soft I want to economize my actions.
Thanks,
Darl (Tarkus)
Is that thinner then some of my vintage thorw away razor blades.
cause i have some vintage blade that fits my Gem Se razors that's like
4 times thicker then my De blades.
I'm wondering is the .050" thick at the cutting edge a good stopping point for grinding before heat treating & then final grinding after the hardening. Or should I take it thinner before heat treating & risk warpage.
You can go thinner .020 or .030, that being said I usually stop around .040 to .050. I like the piece of mind and wiggle room that the thicker edge gives me. I do not mind grinding off the extra material.
Charlie
Thanks so much Charlie you are a big help.Quote:
Originally Posted by spazola
Darl
Also as you are heat treating, you will get scale and lose some surface carbon.
So even regardless of warpage, you still need to material to grind away in order to end up with good steel without scale pox.
I just love that term: Scale Pox
I'm sorry to be so late on this. I've been lost in the post-Ashokan Seminar rat race.
I grind the edges to 0.030" thick on my tool steel blades. I also leave about 0.015 extra on the bottom of the edge as well.
The extra thickness allows for more wiggle room, as Charlie said. The extra width helps allow for decarberization during heat treating, as mentioned by Bruno.
Wiggle room. I stop .040 to .050 (ish). The reason is because of the thin cross section. With other types of tools having thicker cross sections you can significantly decrease the grind allowance.
Anyone remember how thick the decarb layer is when treated in a salt bath or electric furnace?
Jeff
Jeff,
If the salts are properly rectified, there is no decarb. For a regular electric furnace, and a simple carbon steel, plan on 0.005". That will vary depending on soak time.
And atmosphere. This is only a fine point that will likely not apply for guys doing simple stuff in simple shops. Some ovens have a neutral gas (argon, nitrogen, essentially no oxygen) controlled environments. That's expensive, for most of us doing blades, we get good enough compensating by leaving a little skin on the blade without having to add in all that extra equipment and costs. Like Tim and me, it's something we decided to do because we wanted to play with it, or it does make a difference in what we decide we want our blades to be like. Now a big industrial outfit...the stuff is just a tax deduction and worth doing for that, or because some consultant said so.Quote:
Originally Posted by Tim Zowada
Beginners and the insanely cheap (like me) should avoid TAD.
One other thing to consider regarding decarburization...try to avoid high temperatures during the heats/forging cycles. As Tim indicates correctly, the longer the blade spends at a higher temperature the more carbon can be lost from the surface of the blade. When you heat treat, you only really need a temperature just above the critical temperature of the steel you are working. You don't need crazy hot. And, you only want to spend the minimum necessary time for that steel at that temperature if you can. Just enough is all you need.
The main problem is that most fires are unregulated or difficult to control for temperature. Those two things are the primary reasons for wanting a salt pot or oven setup - temperature control. It can be done with gas forges too, but you still have the problem of a more aggressive atmosphere to compensate for oven or forge setup.