Finally grinding my first blade, some basic q's

cpirtle

cpirtle

Leathercrafter
Knifemaker / Craftsman / Service Provider
Joined
Mar 28, 2001
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Hi all, I finally started on my first couple of blades and I'm hoping to have them off to heat treat in the next few days.

I'm hoping you guys could help me with a couple of questions.



1: How thick should I leave the unsharpened edge on my knife before sending it off to HT? I'm working with 3/16" 154CM and 1/8" ATS-34, both are flat ground.

2: What grit do you finish them to before HT? The one I've got 90% done is finished to 180 right now.

3: I'm using a Delta 1x42 belt sander for stock removal, will it be suitable for removing the scale when the knife gets back from HT or should that be done by hand to prevent damage to the HT? I'd like to do a ScotchBrite finish and I have the 1x42 SB belts. I also read that 154CM could stand temperatures up to 700 deg without affecting the temper, is that true and is it the same for ATS-34?

4: Should detail bevels and checkering be left for after heat treat or is okay to do it before HT?

5: How do you guys sharpen the knife for the first time? I was going to use the 1x42 but again had concerns that the high rpm could cause too much heat and damage the HT.

Finally, I find that grinding with my edge up has worked best for me because I can watch my edge thickness and have better control of the angle, but I have heard that very few people grind edge up. Are there any real specific resons to grind edge down? (other than the obvious..)



Sorry for so many questions and thanks in advance for the responses.
 
#1= .015-.030.

#2= 180 grit is fine.

#3= If the scale is real bad, just soak the blades in white vinegar overnight. Then just wire brush 95% of the scale off.
You can grind any remaining scale off.
IIRC, 154CM, and ATS34 are tempered at 900 degrees C. So keep the temps way below that. I grind bare handed after HT, as you hand/fingers will start to hurt at about 110+ degrees. Good early warning. Dip the blades frequently.

#4= You better do any checkering or file work on steel before HT.

#5= I sharpen edge down, on the belt grinder, using 120, then 320 grit belts. Move to the buffer and take the burr off with a felt wheel, and green SS compound. That's just my way, every maker has their own way.
If you don't have variable speed, use a light touch sharpening, and again, dip often.

Finally= Most makers (myself included)grind EDGE UP, but there are a couple who grind edge down.
Good luck to you. :D
 
cpirtle a Knifemaker friend told me years ago your not trying to impress the heat treater its the finished product that counts. I bring mine to 220. Also there are some on here A.T.Barr for one that grinds after the HT. He and others say its easier to grind I have not tried this method.

Goodluck

Glen in Louisiana
 
Chad,
I grind almost all the steels after heat treat. I also grind edge up. Can't imagine doing it edge down. With the belts available for a 1x42, you almost have to grind before heat treat.
Do all the filing, serrating, etc before.
Anything over 120 grit is fine. Chance of stress cracks below that grit. The finer the finish, the easier it is after heat treat.
One point, though. I use variable speed and grind slow both before and after heat treat. Be cautious with the fast speed 1x42. Water bucket with a little soap in it and dunk the blade often on your final grinds and sharpening.
 
Thanks for all of your help everyone. I was finished prepping my first knife and decided to do some tinkering around with it and screwed it all up. So tomorrow night I'll be reshaping the handle to compensate - won't look anything like my original plan but I'm still pleased with it.

That's interesting about grinding after heat treat, you must really have to be careful not to overheat the blade.

I guess I must have ben confused about grinding edge down, after doing it the whole process just felt more natural doing edge up.

Another question though, I asked this before and did not get any responses. I have a local tooling heat treater that will take my blades and is located about 5 minutes from my office. They do not do knives normally but will heat treat based on Crucible's specs, any reason why I would not want to send a couple to them?
 
"why I would not want to send a couple to them?"
They may not know how to heat treat 154 - cm
As far as i know you wouldnt use it for tool and die work but i could be wrong. You should ask them if they have heat treated it before and if not give them a spec sheet and they wont have a problem doing it but a paul bos HT is damn near unbeatable so you may want to go that route
 
i use Paul Bos for my stainless blades. he does add a cryo cycle that the local guy may not do? ask. i send twenty plus blades at a time. paul has a $80ish minumim. if the local guy is $10 or so a blade i am sure it will be a usable heat treat if he use's the spec's. for your first couple i am sure you will be fine. good luck and welcome to the forums. folks like mike and kit will always steer you right.
 
I guess I noticed something. If you send your air quench blades to someone who knows what they are doing you will not have any scale to grind off. Both the steels you mentioned are air quench steels, although can be oil quenched. The blades should either be wrapped or in an otherwise atmosphere control to keep oxygen from causing decarborization. You will have discorolation though that will need to be ground off, but no scaling. RL
 
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