View Full Version : grinding bevel before or after heattreat?


s mcfall
10-03-2013, 11:32 AM
i know i used to grind before heat treat but i have read where some grind after heat treat to eliminate warpage during the heattreat, seems it would eat more belts grinding after thoughts?

Steve
10-03-2013, 01:33 PM
I agree with you, it gets rid of a lot of steel, some heat treaters charge by the pound, shipping is more,
pre-gringing uses fewer belts, and a good heat treater will return them as you sent them, with rare exceptions. Stuff happens.

It's probably harder to grind too much away if the steel if hardened, though and that is a consideration, especially to the new maker. A new 50x belt can grind waaaayyyy too far, waaaaayyyy to fast, if you're not paying attention, or have pretty good skills.

Lots of people do it - both ways - so maybe just try it and see which way you prefer. You can make a knife any way you want to, whatever works for you, until you want to change.
Any other thoughts out there?

SVanderkolff
10-03-2013, 02:54 PM
Actually I do both. I will do a preliminary grind before heat treat, where i am simply trying to eliminate some of the metal and roughly establish a bevel area, after heat treat is when I get the plunge cuts to line up and the edge down to the thickness I want. This seems to be the best of both worlds. Works for me anyways.
Steve

jmccustomknives
10-03-2013, 03:02 PM
Personally I'll take mine to around 80% then heat treat. With forged blades I'll tend to clean them up and get out any of those deep hammer marks to keep any stress risers from causing problems and find any imperfections that may ruin a blade.

racjarrett88
10-03-2013, 03:04 PM
If using thin steel grinding after is pretty easy. Trugrit has cheap ceramic belts that work really well. VSM I believe i use. Last I ordered were $3 a piece and work excellent. It is way easier to mess up before heat treat. Good Luck

Austin Colvin

Icho
10-03-2013, 04:55 PM
I am still fairly new to knifemaking so I am still experimenting to see what works best for me. I have almost completely finished a blade before heat treat and have not had any problems. The last set of knive were just profiled D2 blanks and I did all of the grinding after heat treat. I also had no problems this way either. I am leaning towards grinding after heat treat because like others said it is easier to screw up when it is soft. I look at it as 1 chance to screw up instead of 2. Lol. I am getting some blades ready for heat treat right now and am planning to do what Steve said and do just a rough grind to remove most of the material.

Steve
10-03-2013, 07:07 PM
good thinking, Icho. Take it slow and learn what you like best, then do it. Of course, stay open to new ways of doing things. You can do things a lot faster, I find, than they have been done for yrs. if you will just give it a try and judge for yourself. Mention to your heat treater that you would like them to be kept straight! Peters' does a great job, Paul Bos used to, I assume that they are still running up there in Idaho. Others are out there that do super work, just ask around.

Icho
10-03-2013, 10:12 PM
I am very happy with my heat treater. He did 10-15 blades for me and all were straight. Even my first blade which was o-1 with a sharp edge.

Steve M
10-03-2013, 11:51 PM
I leave about 30% of the meat on the blade as i do my own heat treat and like to have plenty to work with when one warps through my own clumsiness or rough handling out of the furnace. I'm no expert but it works for me.

Just yesterday I lightly hollowed out a bunch of tangs to be tapered in 1/8" stock and was pondering weather it would be a good idea to leave them as is and taper post heat treat. After reading all of your comments on this, that's what I'll do. Thanks guys.
Steve

Steve
10-04-2013, 01:05 AM
Hey Steel Addict, please let us know how it goes for you. OK?

Steve M
10-04-2013, 02:23 AM
Will do Steve!
Yet to grind the bevels. I'll keep you posted

I'll heat treat them all and report back.
Lets see how many i can warp - Hopefully not now!

Steve

Brad Johnson
10-04-2013, 07:53 AM
Steve,

One aspect that has not been discussed is overheating of the steel while grinding post HT. A fresh 50 grit belt will grind well and cool but if there is some wear on it watch out that steel can go from bright to blue to dark brown real quick. I finish grind to 120 grit, HT, then using a fresh 120 grit flexible belt true up everything and bring down the edge to .010-.015 and polish with finer grits. Just my 2 cents!

Steve
10-04-2013, 01:36 PM
Great 2? worth, Steve. We need to watch the heat build-up after heat treat, that's for sure. I might say it'd be a good idea to keep the temp down prior to heat treat, also, if you don't want the blade coming back shaped like a banana. Of course, most heat treaters will stress relieve your blades first, but not all and it doesn't hurt to request that service.
Thank you.

jes4e
10-10-2013, 05:54 AM
I have been using 1095 and cpm steels for the last while, and I have found that when working with a plain carbon steel that is 1/8" or less, that it is best to do all of the grinding after heat treat. The 1/8" is already so thin that it can be hard to keep it from warping. But at the same time when hardening some ats, 440c, or cpm steels I keep the edge at about .030" just to be sure. You can grind them to 90% finished and not have any problems at all. At least this has been my experience doing my own heat treating, and also if the stainless steel warps you have a few min to straighten them out before the hardness sets in. with carbon steel you have only a few moments to get it straight.

Steve M
10-29-2013, 12:18 AM
All 4 ATS-34 blades 1/8" thick came out dead straight. I Hollowed the tangs leaving some full thickness spots at the butt, roughed out the bevels leaving .050" at the edge and plate quenched. Perfect result!

Thanks jess4e for the tip on straightening within a few mins. I never even thought to do that before. A 5/32" 440C blade with a tapered tang came out a bit bent so i just straightened it with hand pressure and it was almost down to room temp. It unfortunately assumed it's original shape after the first temper, but was easy fixed in the second. May have to clamp them straight for the temper next time...