New 24 grit belt - how do I NOT strip it when starting out?

synthesist

synthesist

So many knives so little time
Joined
Sep 14, 2004
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I badly need a clue or 2 here.

For the sorts of things I typically do with my belt grinder I use medium to finer grits - say 80 and up. But I have a project where I'm going to REALLY need to HOG some metal off ( Repairing a BADLY abused broad axe for a friend in the UP). So, while at the Great Lakes Knife Show in Beloit a couple of weeks ago I stocked up on some SERIOUS 24 and 36 grit belts.

In the past I've experienced a shower of grit blasting at me when I start using a brand new coarse belt, which seems wrong, to say nothing of expensive and itchy.

Is there something I can do to preclude this by adjusting my grinder's platen angle or the starting speed? I have a 12" x 1" serrated wheel. Would I be better off cutting the belt in half for this kind of grinding (less surface drag = better cutting than a 2" wide belt) and using the 1" wheel?

I also thought about going at this with a 4 1/2" hand grinder. Would that be better to get it roughed in with?

I'm so confused on this one......

Any thoughts, suggestions or hard earned wisdom shared would be much appreciated. I almost think it'd be cheaper to buy him a new axe, just not as much fun as resurrecting a well made old tool and giving it a new life.

Warm regards,

Corey "synthesist" Gimbel
 
Maybe knock off the 90° angles with the angle grinder first. You’re probably going to get showered with grit either way but knocking the sharp angles off first (if there are any) will probably reduce it.
 
I think Josh gave good advice. I would use a worn belt to make a bevel so you will not be grinding against a sharp edge. I would also do this with a round wheel. Bob Loveless book "How to make knives" has a picture that shows how to do this without stripping the grit off a belt.
 
I think it's just the nature of the beast. Do what Josh and Tom said and then lay into it. Yeah some grit will come off, but it'll remove way more metal per minute than an 80 grit.
 
Hi there, Corey. Good to see you are still doing your thing as it happens. I believe you will find that the 36 will be a real metal eater on that old axe.
Frank
 
I always start a new blade with a used belt until the sharp edges are knocked off and then switch to a new belt to avoid stripping the abrasive off and I think the same would apply to your project. Also if you start the cleanup with a slack belt instead of a flat platen it will save some stripping from occurring. Just my opinion. Good luck with your project. Larry
 
I think you need speed on that 24-36 grit belt . I believe that as coarse you go with belt you need more speed . . . .And probably serrated wheel is not good choice for 24-36 grit ?
PS.My experience is modest with belt grinders, but I think that I experienced a shower of grit blasting at me when I start using ANY brand new belt ,no matter of grit number .And I think that is normal , in manufacturing some pieces of ceramic is not bond strong in the matrix.....I have one 24 grit belt, but I'm still afraid to try it .............It looks like a street from the cobblestones :)
 
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Loose grit just happens. Roll with it.

Is this an existing, already hardened piece of steel, Corey? If you need to pull off that much material, you might be better off just annealing it, regrinding and then rehardening it. You won’t believe how evil an errant 24 grit scratch is to work out of hardened steel...
 
The 3-4 badly abused axes I've reprofiled were done on a wheel, with the bevel inline with the wheel. If that doesn't make sense, imagine the handle was on, it'd be pointing from floor to ceiling. It works well to convex that way anyways, and prevents having to stick something sharp right into the belt. It should result in loosing a lot less grit.
 
I like a good 3M 984F ceramic 60 grit belt the best for hogging. I tryed the same in a 36 grit and don't like the way they grind. I can't tell a difference in time either between the two.
 
I use a lot of 24 & 36 grit belts for sharpening lawn mower & bush hog blades. I find that most of the "loose" grit comes off in 2-3 seconds and then they settle down. I 24 grit belt at full speed will EAT steel like a fat kid eats cake. Like Matt said, be careful because a 24 grit boo-boo can turn a Bowie into a paring knife in short order. LOL
 
Use a flap disc on an angle grinder first on that broad axe,

Then move to the belt grinder
 
I appreciate all the speedy replies......

I already knocked the 90° off so I'm good there. I think I'll attack it with a used belt on a smooth 1" wheel and see how that goes.

If I were more industrious (I'm not) I'd go with Matt's suggestion of annealing it and then rehardening it. Since I have no idea what the metal is other then carbon (rusty) steel I think I'll pass on that solution and take out my hearing aids, put on a welder's cap, face shield, dust mask and leather apron and have at it.

I also love Geoff's idea of doing it blade forward on a grinding wheel except my grinder is set up with soft wheels for fine work on woodworking tools and this might use up an expensive wheel in a hurry. Great idea tho. The grinder I'd do this on is sitting in the shop up north in the UP already being used to sharpen, go figure, axes and various brush cutting tools up there.

My wife says screw it, I should just trash the axe head and buy him something new..... When I explored that solution I discovered the broad axes are expensive (duhhhhh) and now come in rights and lefts which confused matters more. I think this old one was right handed. Anyway, that's my story and Im'a sticking to it. I'm thinking it will become a Yooper (denizen of the 51st State - the Upper Peninsula of Michigan for the uninitiated) deer camp wall ornament as opposed to a tool used in building a log cabin anyway so who'll care or question my decision?

More later.

Corey "synthesist" Gimbel
 
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Just for clarification sake, when I said wheel I was referring to the contact wheel on your belt grinder. I guess I should have worded that better.
 
Ahhhhhh I did misunderstand your idea Geoff butttttt whether going straight in against a wheel on a belt grinder with a coarse belt or straight in on grinding wheel on a shop grinder it'd work equally well I think, so I may just set up a belt and give it a go over the weekend.

I do appreciate the clarification btw.

Corey
 
Generic comment about 24 grit belts:

Cutting them in half does a very bad thing to a razor blade.

Nuff said...................
 
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