View Full Version : Anyone have a hollow grind form for sanding the grind area?


WinDancer
12-23-2001, 08:16 PM
I was thinking [yup- there he goes again] about a form for sanding the hollow grind on blades.

Maybe a piece of pipe the same diameter as the wheel that could be covered with sandpaper and stuck in a vice. Then the knife could be run back and forth across the form to clean up the grind area.

Any ideas?

Dave

DC KNIVES
12-23-2001, 08:45 PM
Dave,I don't do hollow grinds,but if I was making a sanding form for it,I would cut a piece wood and glue a strip of rubber or leather to it. Make the combination the same diameter as your wheel and you should be good to go.Dave

Bob Warner
12-23-2001, 08:53 PM
If you have a grinder and can do hollow grinds now, why not use the grinder as your form? Sometimes I will put a new belt on my grinder and run it around a few times to get it centered. Then turn it off and slide my blade in and out froom the side of the wheel. Works great and you don't need to make anything special.

If you do want to make something else, why not just glue several pieces of particle board together and cut it to the diameter you need? You could cut that in half and tape sandpaper to it, set it on your bench and sand away.

Geno has a thick piece of rubber (He calls it the finger) that he wraps sandpaper around and uses that. It really works quite well.

How do I know? Because Geno gave me the finger a long time ago.

george tichbourne
12-23-2001, 09:19 PM
Up here in the frosty frozen north we use hockey pucks that have been reprofiled to fit the curve of the grind. They work great but you gotta use the rubber kind.

Bob Warner
12-23-2001, 09:31 PM
Hocky pucks is a good idea. I wonder if they are available in Texas. Not much ice here in the winter.

MIKE KOLLER
12-23-2001, 09:51 PM
If you are looking to get a hand finish,or just to help clean up any little flaws use the above mentioned ideas,but remember to put a small radius on the edge of whatever you use.This will help eliminate any chance of scratches in the form of swirls that will ruin a hand finished blade.

Also whatever you make can stand to be a bit oversized(tiny bit) because the dia. is different with different grits of belts.(coarse are larger than fine,as so forth)

doug timbs
12-24-2001, 07:31 AM
If you can't find a hockey puck (sounds like they would work well),pick up a sanding block from an auto paint shop.Cut into blocks and grind to the required radius.Make sure you use the hard rubber kind.I've been using these for a long time and they work well.
Doug

Don Cowles
12-24-2001, 08:04 AM
I use some stuff that is sort of like 1 " thick micarta- it is layers of canvas, but in a rubber matrix rather than phenolic. I got it at a place I used to work, and I *think* it was designed for use as either a shock absorber or electric insulator for heavy machinery.

It bandsawed fairly easily into pieces with radii consistent with my contact wheels (I made an 8" and a 10" version), and I just wrap a 1" strip around the edge. I use it for all of my hand finishing.

Cactusforge
12-24-2001, 09:37 AM
For a 8 in wheel the old fashion sanding block that is sold at the hardware store the rubber kind with a slit in each end that you use to hold the sand paper to the block, the ones at my store have a 4 in radius on the back side, just slice a 1 in thick piece off and you have a sanding blocb Gib

Geno
12-24-2001, 10:40 AM
Rubber is what I use.
Wood, felt, macarta, plexiglass, cork, many things can be used as a backing.
Make your own and find out what works best for you.

winstonknives
12-25-2001, 08:12 PM
Here is something that works for me, though I hardly ever hollow grind. When ready to hand sand I toss a few craft sticks (popsicle sticks) in a bowl of water. After they have soaked for a while they become limber enough to bend. I cut my sandpaper about 3/4" x 4". Then just hold the paper on the stick with your index fingers and push down with your thumbs. The softened sticks will conform to any hollow grind no matter the radius. This also allows some movement at an angle to the previous rub.

Bill Foote
12-26-2001, 03:11 PM
I made one of these for 12" and 8" hollow grinds. Uses sandpaper strips. I used contact cement to bond rubber to wood.
http://wsphotofews.excite.com/040/eo/ub/D7/q424653.jpg

WinDancer
12-26-2001, 09:14 PM
Bill I am dying to see this but I don't have access to the album ????

Can anyone else view the pics?

Thanks,
Dave

Bill Foote
12-27-2001, 11:11 AM
Dave, I edited the pic. You can probably come up with a more ergonomic handle. I just made these and I think I'll shorten the handle.
Bill

Tangus
03-05-2002, 03:01 PM
Neccessity is the mother of invention. I take an old 5/8" piece of garden hose, split it up the side, epoxy it to a 1" dowel rod some 6" long. It makes a pretty good radi when the sheet sandpaper is rolled around it one time--I normally use a little 3m spray adhesive. Guess there are a number of ways to get to the same effect.--Dan

fitzo
03-06-2002, 04:44 PM
I use an old pink rubber school eraser, about 1 1/8 x2 1/2 x 1/2 thick. I cut a longish (8-10") strip of shop roll or cut wet-and-dry to fit widthwise with a paper cutter. Holding both ends of the paper to the eraser is easy and the flexibility conforms to the radius perfect. Keeping the long paper lets you get a good grip with thumb and forefinger. It's worked great for a long time.

Tangus
03-21-2002, 03:11 PM
I tried George's idea with the hockey puck and it works great! thanks for the tip (I even found the pucks in Kansas!)

NickWheeler
03-22-2002, 02:37 PM
Dave-

I know I had my blocks when you were here last... time for a new lesson ;)

Since I don't use dymondwood on my knives anymore I made quite a few blocks for hand-sanding out of that. Almost all of the sanding is done with a hard faced one (simply all dymondwood) and only the last few passes with either 400, 600, 2000 (depending on ending grit) are done with one that has a 9-10 oz leather face glued to it. It will help smooth any uneven strokes...if you start with a leather faced one and use it all the way through you can very easily wash out your grind lines (not important to some...buy VERY important to me).

Time to come back Dave :)
Nick