Flat surfaces

D

Destraal

Joined
May 28, 2008
Messages
135
My biggest problem seems to be getting stuff flat, knife blanks, handle material, bolster material; I just can't seem to flatten them effectively in a timely manner. I have tried using my grinder with a graphite platen, but that seems to just wear down places in the graphite faster than I can get things flat, in addition to it being rather difficult to hold a thin piece of metal flat on said platen. So, barring the purchase of a disk sander, how can I make flat surfaces without spending hours just rubbing it on sand paper mounted to glass or something like that?
 
What grinder do you have? My Grizzly came with a little graphite sticky liner on the platen. If that is what your talking about take it off. What I do is make sure I have all my flats done before I finish profiling. That way if you get any rounded edges you can take them off in the profiling. Also if I really need something flat I put it against the platen with light presure and then turn on the grinder. I add pressure when the grinder is running. Turn off the grinder and then pull the piece away.

I hope this helps.
 
I forgot to mention a little push stick can help hold the piece against the platen. Something with a tiny lip on the end that will go under the piece but not touch the belt.
 
I also have the Grizzly and intend to go remove that graphite pad in just a moment. Do you usually just use your hands to keep the blade or whatever on the platen (as well as the little push stick mentioned in the second post)? Also, won't that platen still wear down as well, or is it much easier to flatten than the graphite platen?

Last question, what about using stones to flatten? Is that very time effective, or even effective at all?
 
I use sanding on a glass block by hand, it doesn't take hours if you flattened roughly on the grinder. Also I've noticed if you run the grinder at the slowest speed and change the directions of the material quickly it helps a lot. Sometimes I've managed to have good flat on the grinder without the need of hand sanding. Some times I use horizontal disk sander attached on my belt grinder's drive wheel, it does decent job...
 
I talked to some guys at the last knife show I was at and here's what I'm going to try. I like you would use the platen first (kmg) then go to a granite block with sandpaper. I ordered some durosharp DMT diamond stones that supposed to stay true and very very very flat. They should be in today. I'm going to go from my platen to the diamond stones then once done there do my final flat finishes on the granite block. I was told it would speed up my time. I've also found that using a magnet, a very stiff belt, and a high speed help flatten on the platen better than anything.
 
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Another alternative to take a 1/4 sheet palm sander,
replace the rubber pad with something hard (I use
1/8 micarta) and mount it upside down. It's not perfect
and it's not as fast as a disk sander but it helps a lot.

There have been a number of threads on this here.
 
I tried removing the graphite pad from the platen, but now my platen and belt get rather hot rather quickly. I'm sure that part of this is because it's a dull belt, but what do you do to keep them cool?.

Thanks for the suggestion dlpierson, I will try that as soon as I get ahold of some micarta. Sorry to post another thread on a topic that has already been discussed, but I did check the stickies and even searched without finding anything.
 
i star off by surface grinding almost all steel, bolsters,guards, and blades, then i have a piece of H13 about 5'' round that i put sand paper or psa disc on and hand sand machine marks out of. also i use a disc sander to flat sand handle material, and then take it back to the same sanding block for final touches.

andrew
 
I use a rough belt on the grinder 120 because the backing is really stiff and the belt wont wear the upper edge of what you are trying to get flat. The problem I had was the upper edge wears more than the lower.

Slow speed, stiff belt and then to glass plate with sandpaper.
 
Flat means flat. I start out with a new belt on the Bader. From there I go to the disc sander with 220 paper. From there I go to a dead flat surface (glass, even new Micarta), spray it with adheasive and lay down another piece of 220 sandpaper. Sand by hand. Takes 30 seconds. At that point it will be flat-flat.

Aside from a mill and a surface grinder, this is the only way to get flat. Burned fingers? Yes. Sanded fingers? Yes. Flat-flat? Yes.

I would advise selling a knife and buying a disc sander. Sell two and get a reversable variable speed. You'll never look back!

Cheers,

Terry Vandeventer
ABS MS
 
tvandeventer said:
Flat means flat. I start out with a new belt on the Bader. From there I go to the disc sander with 220 paper. From there I go to a dead flat surface (glass, even new Micarta), spray it with adheasive and lay down another piece of 220 sandpaper. Sand by hand. Takes 30 seconds. At that point it will be flat-flat.

Aside from a mill and a surface grinder, this is the only way to get flat. Burned fingers? Yes. Sanded fingers? Yes. Flat-flat? Yes.

I would advise selling a knife and buying a disc sander. Sell two and get a reversable variable speed. You'll never look back!

Cheers,

Terry Vandeventer
ABS MS
Click to expand...

I suppose the general consensus is that I should get it roughly flat on the platen and then take it to the glass or micarta. Trust me, I do plan on buying a disc sander, but my knives are not ones that meet my quality standards to sell yet, much less sell for a big enough profit to buy a disc sander. Doesn't help that I'm a poor college student without a job.

Also have to wait till my tang stamp arrives to start selling. :cool:
 
Here's what works best for me.

1. Remove graphite crap (I see you've done that)
2. Go to Ellis Custom Knifeworks and by the 2"x9" ceramic platen liner.
3. Get some JB Weld and when you receive the ceramic platen, mix the JB Weld and spread liberally on the platen. Clamp lightly (just enough to hold it on or you'll crack it!!!) and let sit for 24 hours. Check it once in awhile to ensure it hasn't slipped. You can remove the metal platen for the process. It makes it easier to clamp it down on a flat surface.
4. When you grind your flats, get a welder's magnet like this one and cover the long flat face of the magnet with some blue painter's tape to make cleaning it easier. This will allow you to peel the tape off when it gets too built up with grindings, rust, etc. Then just replace the tape. place the flat face on the magnet and carefully hold up to the platen. Yes, use sharp fresh belts. You will develop a feel for when you are flat on the platen. DO NOT PRESS HARD! This will cause the piece to bump and pull causing more unevenness. You will get dips also that are a b***h to get out. Yes, I've done this. It sucks!

Feel free to email me if you have any more questions. The Grizz is a love / hate relationship. I have a Bader II that still have to hook up but honestly, I've gotten used to my Grizz over 2 years and don't hate it nearly as much as I used to. :D
 
TekSec said:
Here's what works best for me.

1. Remove graphite crap (I see you've done that)
2. Go to Ellis Custom Knifeworks and by the 2"x9" ceramic platen liner.
3. Get some JB Weld and when you receive the ceramic platen, mix the JB Weld and spread liberally on the platen. Clamp lightly (just enough to hold it on or you'll crack it!!!) and let sit for 24 hours. Check it once in awhile to ensure it hasn't slipped. You can remove the metal platen for the process. It makes it easier to clamp it down on a flat surface.
4. When you grind your flats, get a welder's magnet like this one and cover the long flat face of the magnet with some blue painter's tape to make cleaning it easier. This will allow you to peel the tape off when it gets too built up with grindings, rust, etc. Then just replace the tape. place the flat face on the magnet and carefully hold up to the platen. Yes, use sharp fresh belts. You will develop a feel for when you are flat on the platen. DO NOT PRESS HARD! This will cause the piece to bump and pull causing more unevenness. You will get dips also that are a b***h to get out. Yes, I've done this. It sucks!

Feel free to email me if you have any more questions. The Grizz is a love / hate relationship. I have a Bader II that still have to hook up but honestly, I've gotten used to my Grizz over 2 years and don't hate it nearly as much as I used to. :D
Click to expand...


Erik If you are so used to your Grizz maybe you shouldnt even bother with the Bader. Heck you should probly send it to me. I could send you my grizzly and then you could have two.:D

All jokes aside the Grizzly is really not so bad for the price. But I will sure be glad when I finally am able to move on to something better. As in variable speed, multiple wheel sizes, and a nice small wheel attachment.
 
My method is a little different. I have a 6 X 48 inch grinder and will take a billet, or a 1" X 2" pc. or whatever I want flat and weld a 1/8" bar that is 1/2" wide by 15" long. Then use a block to hold pc to be flattened on the 6" X 48" grinder and use the flat bar as the handle. Works great for me.
 
Even with a milling machine, surface grinder, and reversing variable disc theres still gonna be some flat hand sanding, but as has been said you will never look back.
Ken
 
Des, You might try making a little hollow on the interior (non showing) part of the surface you are trying to flatten. Then it may be easier to flatten just the outside 'rim' instead of an entire surface.

I wouldn't worry too much about belts and running heat, but don't count on your metal platen to be flat or stay flat. You might also consider a magnet to hold thin and hot parts, so you can concentrate more how you lay your item against the running belt.

Off of a good flat platen, you might be able to get very close to a nice seam between two materials.

Good luck with it, Craig
 
I never could get anything dead flat and slick till I made a horizontal disc sander with a geared motor that ran at 60 rpm. It ran nice and slow so you could control what you were sanding and keep it in contact with the disc without getting it hot and lay it on the disc flat instead of tipping it and hitting one end or corner first like you do on a regular speed sander. Even if the piece slipped out of your hands it stayed on the disc instead flying across the room!
I want to make another one of these for sure! I don't see how you can make a good folder without it!
 
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