Surface Grinding?

Brian Avila

Brian Avila

Joined
Jan 2, 2011
Messages
1,286
So it has been suggested to me many many many times in the past couple of weeks that I should buy a surface grinder.

Right now I can't.

But people have also suggested finding someone who does have one and then getting my folder blades surface ground there.

My question is. "IF" I can find someone to surface grind them and I could only go to them once in the process, ( I would probably have to pay them ), would it be good to cut everything out and then surface grind it while it is soft. then heat treat and true it up on the granite plate?

The blades would be stainless and heat treated drilled but no bevels etc.

I don't know anything about surface grinding and then any crazy warp after ht for folders.

-Brian-
 
- keep blade parallel before and after heat treat

I'm currently hand lapping before and after heat treat but it is slow going... I want a surface grinder too.

If you do surface grind you will still want to flatten one side (convex side if warped) on a disc grinder. After that move to a surface grinder flattened side down. This will help keep things parallel as your surface grinder magnet can bend the blade.

I'm looking into double disc grinding for parallel blades... before and after heat treat possibly. Grind both sides for parallel parts...

Blades move during heat treat, it may only be .0005" but that can cause issues on a folder.
 
So do you leave a little bit of "meat" before heat treat to hit your intended thickness after heat treat since you are shooting for something?
 
I may not be any help but, I will share my process and answer any questions I can. Fixed blades; I surface grind and grind the bevels after heat treat. Folders; I'm only on my third folder so, I'm still figuring things out. I think I like surface grinding before heat treat because I can run in my bearings creating a slight race in the blade. It's probably not critical because I am machining some fairly precise pockets in the liners but, it is a nice touch. I don't know that I've ever had (or noticed) a problem with warping on any blade I've heat treated myself. Surface grinding does go much faster on annealed steel so pre-HT might also save you some money if it works for you.

Bob
 
I am just curious about what others do...

I can't find a machine shop to help me out anyways...yet. And I don't know any makers close to me who have a surface grinder.
 
I recently got a surface grinder, but it's not installed in my shop yet. My process on folders has been to dial in the flat before and after HT with a combo of platen and disc grinding and hand lapping, doing most of the bevel grinding before HT. I think I may move to surface grinding before and after HT, and grinding bevels after HT and surface grinding, as I recall watching Ken Onion do at his shop. For smaller blades I don't find doing all the bevel grinding after HT to be too big of a chore.

If you could only surface grind once, I'd do it after HT. Getting them pretty flat prior to that isn't too hard. You could leave the blade just a few thou oversize on each side, HT, then grind down to your planned finish thickness, without the possibility of any HT warp afterwards.
 
You're in fort Collins. That's about 45 mins from me. I will ask a few machinist buddies and see what they know about surface grinding and a machine shop for surface grinding.
 
Harden Knives said:
You're in fort Collins. That's about 45 mins from me. I will ask a few machinist buddies and see what they know about surface grinding and a machine shop for surface grinding.
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That would be awesome. Please let me know. I have called around all over northern CO. No luck yet. One guy in Denver wanted a ton of money just for a minimum. So.... Yeah
 
Brian Avila said:
That would be awesome. Please let me know. I have called around all over northern CO. No luck yet. One guy in Denver wanted a ton of money just for a minimum. So.... Yeah
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Stop calling. Go driving. Find a little shop that you can actually talk to the guy that owns the place. I have had good luck with little shops. The big shops want volume. Of course, cash talks too, especially to an owner.
 
Yeah. That's not going to happen. If they don't want to help and talk about it on the phone I am not going to give them my business. I can't afford the time or the gas to drive around the eastern slope of Colorado.
 
Look into double disc grinding too, I need to find my old links but I know some of the shops you find online will take on small jobs.
 
Daniel Fairly Knives said:
Look into double disc grinding too, I need to find my old links but I know some of the shops you find online will take on small jobs.
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Yeah, you are the first guy to have said anything about that. I was meaning to ask you what it was. I really need a disc grinder and this would probably be much easier by hand but like every other tool for my shop. Arm and a leg.
 
Brian Avila said:
Yeah, you are the first guy to have said anything about that. I was meaning to ask you what it was. I really need a disc grinder and this would probably be much easier by hand but like every other tool for my shop. Arm and a leg.
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A disc grinder will be my next major purchase i know that! I'm getting good at hand lapping though. Wax on, wax off. I mean stay in a steady figure 8! lol


Double Disc is a much different process despite the similar names... parts are put in a machine (sandwiched between two discs) that grinds both sides at once. You need a few parts for it to work well from what I understand but it is extremely effective.

If I recall correctly Chris Reeve Knives uses the double disc process before and after heat treat on folder blades. Many of the major Framelock makers are too...
 
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