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

Dan
Theknifemaker.com

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.

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.



http://www.beaumontmetalworks.com/rotaryplaten/Mvc-018.jpg


http://www.beaumontmetalworks.com/rotaryplaten/MVC-113E.JPG

Just some food for thought.

Sincerely,
Rob

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

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.

Thanks Steve. Sure worth a trY.

Dan
theknifemaker.com

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:D iI get them from tru-grit.
Hope this helps.

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...

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

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

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

Thanks Steve,

Got to go measure my platen.

Dan
theknifemaker.com

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

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.

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!

Steve, I can give you a word picture: envision a piece of 1/4" thick plate glass the same size as your platen. It is attached to the platen with epoxy or J-B Weld (that's what I used). Stays flat for sure.

Steve,

Here is a pic of Steve's pryoceram liner. It is attached with epoxy.

http://www.fototime.com/043D6EFCBEC533A/standard.jpg

It looks like glass and holds up very well.

Bob Sigmon

Thanks Bob; that's a good pic! I tried taking some pics of the pyro but it looked like, well..glass. Thanks again.

Steve

Great help, those pictures.

How would safety/auto glass work????!!!!

How much was that piece?

A quote form the CKD Buy/sell/trade forum:

I am keeping the following sizes in stock, and can get most any size custom cut for an additional $2.00 per sq. in..

2X6in. $20.
2X7in. $24.
2X8in. $28.
2X9in. $32.

Prices include free shipping. Thanks.

Stephen L. Pryor
HCR1. Box 1445
Boss, MO. 65440
www.stevescutlery.com
573-626-4838

http://ckdforums.com/showthread.php?threadid=2711.

Steve,

The Pyroceram that Steve P. sells is a heat resistant material. Probably not unlike that Corning Glassware that you can use in an oven, Glass pots and pans that are available. Different from window glass.

Bob Sigmon

What are all the advantages of using this material? Has anyone had it crack and bust a belt?

Dan
www.theknifemaker.com

Dan,

Usless you take a hammer and smash your platen, it is not going to break.

If anything, belt life is extended because the pyroceram is smoother. I also made sure that all the edges were radiused before gluing to the metal platen. The platen itself retains no heat. My metal platen would gather and retain heat as I ground.

All in all a good addition to any platen.

Bob Sigmon

Some of the pluses I've gotten reports of is as Bob mentions heat reduction, and reduction of belt thump and worm trails, excellent flat grinding and plunge cuts... I'm sure there are others but it's early.;-)

Thanks guys,

How do you raduis?

Dan
www.theknifemaker.com

Dan,

I just carefully used the flat platen and a fine grit belt. I just worked the edges and kept checking everything with a square. It may not be an exact radius but I haven't had any problems either.

Bob Sigmon

Been using the pyroceram glass from Steve, for about 10 days now. Made my finishing 50 % better, less time involved, and my belts are lasting longer. Wish I had gotten the pyroceram 10 years ago.
Ken (wwjd)

Verrrrrrrry tempting!

The pyroceram edges will grind just like steel on your grinder. Make your edges with as much radius as you want. You will at least want to radius the top and bottom edges. I suspect you'll want to radius the edges at least some to stop them from chipping. When you epoxy it down, make sure your platen is dead flat or the glass will crack. Right off, you'll notice the belt seems to slip much easier and the heat build up is slower.
It's the way to go.

So, are you suggesting that we surface grind the platen face? Won't the epoxy kind of smooth things out, if you don't clamp it down too tight?

I'd assume that you MUST use very good dust precautions when grinding this glass-like material??

I have had no problems at all with my pyroceram to platen glue up. I was relatively generous with the epoxy and just used spring clamps to hold it in place while curing, so as to not get too much squeeze out of the epoxy.

Grinding with the usual dust precautions, mask and collector, works just fine. The silica that it puts out is probably no worse than the silica grit thrown up when starting to use a new belt.

The side radius is real nice for easing the plunge cuts!

But that just my opinion.

Bob Sigmon

I noticed an added bonus. Besides all the other listed benefits, when I installed a piece of pyroceram on the platen of one of my Burr-Kings knifemaker attachment, the top wheel runs about 60-75% cooler. It had been running so hot previously, that I was waiting for the bearings to seize.

Hi Mike; I never thought about it keeping the other wheels and bearing cooler but it does make sense since the belt is running cooler to start with. Thanks for pointing out this observation.

Steve

Originally posted by Steve
So, are you suggesting that we surface grind the platen face? Won't the epoxy kind of smooth things out, if you don't clamp it down too tight?

Yes and no.
Some time ago I epoxied a 1/4" tempered glass piece to a platen. It was not completely flat, which was visible when glueing it up. I clamped it with spring clamps but the glass must have bent slightly. When it cured, the glass had cracked from the stress. Problem is it continued to fracture in several places. I still used it and it worked better than a plain platen but will probably need to replace it soon. On my other grinder, I used the pyroceram and I made sure the platen was flat by running a large flat file across it and used JBWeld. This time no crack and it is holding up.

Steve's a bum. Just because that pyroceram works great is no reason he should charge us for it. Just because he has to pay for it and then run to town to ship it is no good reason to charge us.

And on top of that, he just held me captive for a few days in the middle of nowhere in Missouri down this marvelously curvy dirt road (actually, rocks...no such thing as dirt in the Ozarks) that I had to suffer thru 4x4 forays for days. On top of that he made me eat all that chicken and dumplins, beans, and other great cooking Tammy made for us....it was just terrible. hehehe

Actually, the pyroceram works real good, and I have it on both platens. Highly recomended. Just stick it on that funky old steel platen with epoxy or zap-a-gap methacrylate. No surface prep necesaary unless it's goo'd up.

BTW, did I say "Steve's a bum"? ;)

Thanks, Steve and Tammy, from the bottom of our hearts. Paltalk has made us some great friends for life, and we cherish them all. You too, Koller.:p

Now, that's what I call an answer to the "Belt Bump" question.

Thanks, everyone! I'm gonna try that platen attachment, for sure. (Did I say that already?) :rolleyes:

Fitzo; thanks for your kind words, you guys are welcome here anytime my friend. Maybe next time we'll fire up the ol jeep and show ya what 4 wheelin is.:D
Steve; sorry, didn't mean to turn this into a pyroceram thread but that could possibly be the solution to belt bump and several other steel platen related problems.

I appreciate all the comment. That's what I meant, I'm not complaining, but celebrating, the fact that so many makers, etc. are so willing to help.

I'm sorry if you felt that I was complaining. I've never even hear of that product and hope, certainly, to pick one up someday soon. As soon as I can afford it. I was told today that I need a new car, by a stranger! First things first, huh?

Oh no, I didn't think you we're complaining at all. I just felt a bit guilty for turning the thread around.
I know what you mean...we just had a stranger tell us we need a new vacuum.lol
Boy we do have a great bunch of knowlegable people here that are very willing to help (ceptn those that call me a bum).:cool:

I am gonna get one of those pyro-thingies for my platen too, sounds like a good thing for wear. But; I have a question. If this thing is harder and more wear resistant than a steel platen how can it decrease belt bump? Bump is caused by the joints of the belt not being perfect, right? Hard is hard whether it be glass, steel or whatever. Just wondering, I coulda missed something thru here. mw

This is a hard one for me to find a scientific explanation for too. It just doesn't make sense that it is definately a harder material but yet provides a somewhat cushy and more controlable feel...Just one of those things that makes ya go hmmmm I guess...

Boy, with this thread I do believe I got some good avice. Thanks guys. I have resurfaced my platen and plan to get some pyroceram.

Dan
www.theknifemaker.com

OK. Like Steve asks, can someone explain why this hard glass-like surface reduces the "bump."



Please.......

Maybe it's more of an "perceived" reduction in bump due to reduced drag, or friction on the back of the belt when rubbing against the smoother surfaced of glass, as opposed to steel?

I've had my pyroceram on the platen for two weeks now and couldn't be more pleased with it. Thanks, Steve. The biggest advantage and the main reason that I ordered one is that now my platen is no longer magnetic. Since I often hold a blade with a magnet to surface grind them, in the past (especially with thin blades) the magnet would grab the steel platen. That's no longer a problem and that alone made the pyroceram worth it.

:) :) :) :)

Gary

Yet another advantage I hadn't considered! Keep em comin guys. Thanks.

He He He,

I just ordered some on/off magnetic bases the other day. Cause the platen isn't MAGNETIC!

Bob Sigmon

Can you get round pyroceram say 9 or 12 inches? Hum, disc sander faces, it wouldn't be beveled but mine isn't anyway.

Thanks for the suggestion Bob. Pyroceram disks (not beveled) are now available cut to size. Thanks again.

I was very involved in introducing this "feature" quite a while ago in this forum but under another topic. I have used this for at least eight years now and have never wanted a change except for when I wanted to hollow grind of course. You can also use silicon to attatch the glass to your platen and unless your patten has a very severe area of wear there is no need to surface grind or relevel it The glass called neoceran is also an excellent product to use.Plate glass just because it can be thick is prone to cracking.The reason there is not as much (I didn't say no ) belt bump is because the belt slides by easier because of the glass surface compared to metal. Hope this helps Frank

In my 30 + years of grinding blades I have used only a Burr King

2 by 72 inch........8 inch and 2 by 4 wheels ,..Mr. robert Fink

your flat grinding attachment is the answer to every problem

I ever ran into rough grinding a blade .....My question is.....

How do I get one.? these forums are great .!!!!!!

Lloydhale@surfmore.net Lloyd

Lloyd; if refering to the pyroceram platen liner, just shoot an email to me at knives4u3@juno.com . Thanks.

lloyd -
mouse click here (http://www.beaumontmetalworks.com/) for rob's web site.

Thanks Wayne...!