do you heat treat before grinding???

C

chad2

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Sep 2, 2011
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i was watching one of snody's videos and it looked like he was heat treating blades with no grinds on them.

and this would make sense for a plate quenched blade which is what i am working with (154cm) does this give you a better quench?

seems like it would but it would aslo make the grinding very hard because you would really have to watch how hot the blade gets and the grinding would take like 10 times longer is it worth it ?

http://www.youtube.com/watch?v=KCuI6BPJb_I

here is the link go to the 1 min 41 sec mark and the blades he is putting in the foil look like they have no bevels on them.
 
After five seconds of Snody's video, I turned it off. I have tried to watch his videos before, and they do nothing but give me a headache.

You can do bevels after heat treat. If will eat belts faster, and if you burn the blade in the hardened state, you will have to HT it again.

It would not affect the HT to any great degree if they are ground prior.
 
Will grinding heat hurt the heat treatment on air-hardening steel?
 
I use CPM-154, 154CM, Elmax, ATS-34, etc.....

I have ground blades before heat treat, and after heat treat. Grinding before heat treat you don't have to worry about overheating, but there is a bit more labor in the finishing process. By grinding after heat treatment, you get the advantage of going through all of the grits just once rather than twice, but there is the danger that you will get the blade too hot and have to re heat treat, which = not good:thumbdn:, because basically what would the point be to heat treat first.

Personally, I think for medium to larger fixed blades there is no reason to not grind pre heat treat, just due to the natur of the blade and how easy it is to finish. As far as folder blades, which in my opinion are harder to get the grind jsut right on, I would suggest grinding post heat treat. Also, after lots of labor trying to line up my swedges just right for finishing after heat treat, I've decided that from here on out I will grind all of my swedges after heat treat.....and while I'm back to that subject, after heat treat, as long as you grind your blades holding them with your bare hands you should be ok. As far as I know, the steel will get too hot for you to touch it way before it gets hot enough to mess up the heat treat, so go by that and you don't have to worry about messing up your hardened steel.
 
Like Johnnymac , I grind big thick blades pre-HT and small thin blades Post-HT.

The post -HT grinding is done on fresh belts, with bare hands, and a dip tub placed right below the belt grinder. I grind until it gets too warm to hold, dip, grind,dip, etc. On a thin blade, like a fillet knife, the total grinding time is far less than doing it twice. If you do it bare handed, you will not likely ruin the HT.

On long blades, like a sashimi/yanagiba hocho, I will only roughly grind in the bevel and taper. Basically, I just clean up the forging to 120 grit, and do the HT. This is to reduce twist and warp in HT. The details are ground after HT.
 
I do allot post heat treat, but I alos tend to use HSS so the heat isn't as much of a factor
 
Bill DeShivs said:
Will grinding heat hurt the heat treatment on air-hardening steel?
Click to expand...

In theory, air-hardening steels are designed from the outset to withstand higher temps before harming the temper. In practice, you want to keep any type of steel cool after HT to be on the safe side, so I don't think it matters a whole lot if the blade is 1095 or D2 or CPM-154. I've gotten in the habit of grinding bare-handed and cooling often whether grinding pre- or post-HT. The amount of heat we're talking about probably doesn't matter much or at all pre-HT, since any good heat-treater will employ some manner of stress-relief cycle before austenizing anyway. I just don't see any reason to stress the steel, and figure keeping things cool is a good habit to keep. Hot steel has a tendency to make me say bad words and drop things on my toes :o
bladsmth said:
Like Johnnymac , I grind big thick blades pre-HT and small thin blades Post-HT.
Click to expand...

Generally, I agree. However, when it comes to highly wear-resistant steels like CPM-3V, I do as much grinding and sanding as possible before HT. Simply because hand-sanding takes forEVER afterwards, and Brad at Peters' HT does an excellent job of keeping my blades clean and straight, so I may as well do as much work as I can while the steel is relatively soft.
 
I grind hunters, neck knives and others pre-heat treat. I have been making a lot of kitchen knives lately and those I grind post heat treat. For the steels I use it really only takes about twice as long to grind post heat treat. I learned a long time ago that any heat while grinding pre-heat treat contributes to stress in the blade and I am used to dipping frequently and not overheating the blade at all.
Del
 
I grind most fixed blades of any length before HT. I grind folder blades and finish them pre-HT, then send them out to Bos. Never have a warp, always come back clean, just a little cleanup. Large thin blades like chef knives I grind to 90% before HT, then thin the edge out and finish grind after HT. Edges that go into HT at .010" do not stay straight. Clay does NOT help.

My teacher Ken ground most of his folder blades in a hardened state. IT does make sense to me to do it that way, I probably would if I HT'ed my own.
 
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