belt bump

[Dan Graves]

Any suggestions on how to get rid of that nasty belt bump on fine grit belts?

Dan
Theknifemaker.com

[Steve]

I just make sure I buy the "butt-joint" belts that don't have a bump. Not the ones with a "lap-joint."

Also, when polishing on a wheel, a sofeter 40-60 durometer wheel makes it a lot nicer.

[Rob Frink]

Dan,

I've developed these rotary platens for the Bader grinders, the BurrKing, and my KMG1.

The concept is that a serpentine belt is tensioned around the rollers in the attachment, Then the abrasive belts rides on the outside while being supported. The serpentine belts is soft and cushions the thump from the belt seam. The serpentine belt rotates with the abrasive velt so that you don't pinch the abrasive belt between your blade and the hard traditional platen.

The finishing performance is fantastic.








Just some food for thought.

Sincerely,
Rob

[Dan Graves]

John,

I liie your set up. I have used a stay brite belt put on first then my grit belt over the stay brite belt. It works at slow rpm but dosnt always run true. Do you know of a material that you could use on the platen to soften the bump? Thanks.

Dan
theknifemaker.com

[Steve]

I think Bader used to sell a self-stick on Teflon pad for platens. They work ok if not too much pressure is put on them. Can't hurt to try it if they still have them.

[Dan Graves]

Thanks Steve. Sure worth a trY.

Dan
theknifemaker.com

[HermanKnives]

Dan, how fine of grit you wanting to go? the only belt I have found in 400 grit that has absolutely no bump on a hard steel platen is hermes j-flex blue belts with yellow cloth backs. they seem to last a very long time also. I flat grind all my blades and tried everything. The graphite platen stuff bader sells has "give" to it so you dont get a true flat. I made hardened steel platen covers I surface grind back to true after any wear from grinding and the hermes belts work great iI get them from tru-grit.
Hope this helps.

[StevePryor]

I've had a lot of good feedback from those getting the pyroceram liners from me saying it takes a lot of the thump out. Can't really explain why it would since it's hard as. well...glass, and outlasts any other kind of platen, steel or otherwise. Many say it provides a totally different, and more controlable feel...

[Dan Graves]

Thanks guys,

Ive been grinding for 11 years and have never considered the wear on platens. It all makes sense now that I think about it. The hermes belt in 400 sounds good and is fine as I do on a grinder.

Steve, You talked about pyroceram platen material. Is it good for all grits, and how do you apply it. How much is it and can I get some? Again, thanks.

Dan
theknifemaker.com

[tmickley]

Beside Rob's rotar platen, try Nortons Norax belts. Almost no bump since they are so thick.

[StevePryor]

Dan; a bit of information concerning pricing and mounting of the pyroceram can be found here.. http://ckdforums.com/showthread.php?threadid=2711. Thanks.

[Dan Graves]

Thanks Steve,

Got to go measure my platen.

Dan
theknifemaker.com

[Bob Sigmon]

Dan,

Steve's Pyroceram platen liner is great. Combine that with the Norax belts and there is no bump and no heat build up on the platen. The Norax belts are great on wheels for hollow grinding also. They have the flatest joint that I have seen.

Bob Sigmon

[Terry Primos]

I have heard nothing but good things about the Pyroceram platen liners that Steve has. And I've heard about them from a lot of people. I do plan to get one soon.

[Steve]

Very interesting....Can anyone show us a picture, or link us to same? I went to Steve's site and couldn't find a photo, or reference to the pyroceram platen liner.

Sorry!