More simple grinding and belt questions

PIndelicato

PIndelicato

Joined
Sep 16, 2002
Messages
1,577
Almost everything I've read and seen (or maybe focused on?) regarding grinding has been about bevels, plunges, etc. I don't recall much about flats, ricassos, etc. Do people grind these on the grinder too, or sand them by hand? If so, on a platen or wheel or??? Before, during, or after completing the bevels?

Secondly, I have a Craftsman 2x42 and I've realized that the belts I got from Trugrit are too stiff for nice plunge blending (X weight I believe). I see they have the following belts in 2x42:

02x042:242-120-309 2x42-120 LS309J Aluminum Oxide $2.20 KLINGSPOR

02x042:242-500-309 2x42-500 LS309J Aluminum Oxide $2.25 KLINGSPOR

I believe these would be J weight belts? Which, or both, would be best for doing the plunge?

I also see the following 1x42 belts available there...would these be better than the belts above for the plunges?

001x42:142-120-406 1x42-120 RB406JF Aluminum Oxide $1.65 HERMES

001x42:142-150-309 1x42-150 LS309JF Aluminum Oxide $1.75 KLINGSPOR

001x42:142-220-309 1x42-220 LS309JF Aluminum Oxide $1.75 KLINGSPOR

001x42:142-320-309 1x42-320 LS309JF Aluminum Oxide $1.75 KLINGSPOR

I'm guessing these are JF, or 'J-flex' that I keep reading about? Of these available options, which weights, widths, and grits are best for the plunge area?

Thanks!
 
Flats are generally ground on a platen or disk to get them down to clean steel. Final finishing can be anything you want it to be - buff to mirror, hand rub with fine grit paper, or a quick and dirty Scotchbrite belt finish - depending on the type of knife you are making.

A disk grinder will get things flatter than a platen, but the abrasive won't last as long (because of the smaller area of abrasive used.) You can also more easily finish to a fine grit on a disk, as a thin, fine grit belt running over a platen tends to bounce the blade, and you end up with an inconsistant finish and dished out areas. This can be alleviated by using the new "Gator" belts from Tru-Grit, which are thick despite being fine grit. I generally finish the flats to 400 Gator on the platen, then 600 on the disk, then hand rub with a leather faced flat block using 600 wet-or-dry paper.

When I was a beginner, I found grinding the bevels to be much easier if the flats were completely finished first, as I tended to screw up my bevels trying to finish my flats. The only problem was spending a lot of time finishing steel which was going to get ground away later anyway. Nowdays, I rough grind the flats with 60 grit down to clean steel, then grind the bevels, then finish the flats, then re-grind the bevels back to where I want them.

Yep, the "J" indicates J weight and the "JF" indicated J-Flex. I usually form the plunge with X-weight 60 grit on which I have "broken" the corners by running the belt off the edge of the wheel and pushing a scrap piece of steel into the edge of the belt when running. I refiine the plunge with the J flex when I get to finer grits.

Here's a secret: I keep a couple of Klingspor CS411 60 grit belts around for those times when my plunge just doesn't want to form right. The CS411, despite being an X-weight belt, forms beautiful plunges - something to do with the backing on it, I guess. It's an aluminum oxide belt, so it doesn't grind as fast or last as long as the ceramics, which is why I don't grind with it all the time - but it can be a lifesaver at times. I believe the number is the same for 2X42 belts (I use 2X72) but check with Tru-Grit to be sure. They're very helpful people.
 
Thanks to both of you for the informative replies! I've practiced grinding on 2 or 3 blades and some things have gone right, most have gone wrong, but I think I've learned a lot in the process and hopefully on the next ones I will begin putting everything together. I just occurred to me looking at the ones I've done so far that I had no idea how to address the flats (besides all hand work), and did not know what order makes sense for the whole process.

When I ordered my first round of belts from Trugrit, the rep on the phone didn't seem to know a whole lot more than I did, so I didn't get a lot of guidance. I will contact Klingspor directly.

One clarification if you don't mind, is there a large difference between J weight and J-flex belts?
 
the best deal I have found for my 2X42 Craftsman is on Ebay I get 10 for 12.00 from a seller on there I can send you the info for her if you like.

I had real good luck with my first order from her and they work great. Problem is I want a 2x72 so the belts will last longer LOL
 
Sure Larry, I'd like to check out that option.

I haven't called yet, but Klingspor's site says they only sell to distributors and businesses of which I am neither...
 
No problem I know the belts for that thing are spendy when you think of how fast they wear out with only 42"
 
is there a large difference between J weight and J-flex belts?
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Yes. The weight of the backing is the same, but the J-Flex are a lot more flexible. Try both and see which you like better.

Unusual that Tru-Grit wasn't able to provide you with guidance - maybe they just didn't have the right people in the office that day. Klingspor is known to be knifemaker friendly, so even thought their site says they don't sell to individuals, I think it would be worth a call to them anyway. Tell them you're a knifemaker.
 
A. Brett Schaller said:
Yes. The weight of the backing is the same, but the J-Flex are a lot more flexible. Try both and see which you like better.

Unusual that Tru-Grit wasn't able to provide you with guidance - maybe they just didn't have the right people in the office that day. Klingspor is known to be knifemaker friendly, so even thought their site says they don't sell to individuals, I think it would be worth a call to them anyway. Tell them you're a knifemaker.
Click to expand...

They were friendly and tried to be helpful, but didn't seem to be all that knowledgeable in the area of grinding knives. You are probably right that I called at a bad time.

I'll give Klingspor a call and see what they say. Thanks again for the advice, Brett!
 
John Williams is the knife making rep at Klingspor. They sell to all knife makers, regardless of how big you are or whether you are a business or not. John is knowledgeable and friendly. He calls me once a month just to say "Hi" ( and see if I need any more belts).
Stacy
 
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