homemade rotary platen?

M

mike-E

Joined
Mar 2, 2013
Messages
400
anyone ever make their own? i plan on building one around a belt, but havent decided if i want three wheels or four. is there any reason 3 wheels wouldnt work?
 
mike-E said:
anyone ever make their own? i plan on building one around a belt, but havent decided if i want three wheels or four. is there any reason 3 wheels wouldnt work?
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If you have the capability, making a rotary platen doesn't seem that hard. If you're going to make one, you might as well make it with four wheels as it will give you more flexibility. You get less give in the shorter gaps. Also, if you're making one, I can see some benefit to having a larger wheel in one of the positions; maybe 3-1/2 or 4 inch. I do not really change the position of mine. I experimented with it in the beginning, found the best position for me and have left it that way. If I did convex grinds, I might have to rotate it to a different position.

Bob

Bob
 
I use one extensively for convex grinding. I use the biggest span exclusively. I've tried spinning it and using the smaller ones, but it seemed like a novelty and put the wheels too close to my work. Your idea seems like a fine one except for one thing. I wear out the wheels crazy fast. They only last me a month-ish. Not only do the bearings wear out quickly because of the tension, but the wheels actually cup. I am always looking for a better solution but haven't found it yet. I'm excited to see what you do.
 
I have had Fiddleback's experience ,too. The bearings don't last long. I have replaced two belts and several sets of bearings. Still, I love the thing. There are a few convex tasks it excels on.
 
The ones KMG makes have grooves. You'd have to have something to make sure the belt wouldn't come off the wheels.
 
fiddleback, do you think the wheels should be steel? maybe with shoulders on both sides of the wheels? possibly go with bigger bearings?
 
I have yet to see any contact wheels or other grinder components supplied with anything but the cheapest bearings. Most of the bearings I've seen used are rated around 3600rpm. A 2" wheel running at 2000sfm is turning at over 3800rpm. Cheap bearings on a big wheel are really no big deal but on a small wheel they are getting a serious workout. I would think that using some ABEC-7 bearings would probably solve most bearing failure issues.

Bob
 
ill def. spend the money and get good bearings, probably go with bigger wheels too. can any of you guys tell me what size the beaumont belt is? the closest j belt i can find is a 20 rib but it's only 1.84'' wide. the belt is a 2'' width right?
 
mike-E said:
ill def. spend the money and get good bearings, probably go with bigger wheels too. can any of you guys tell me what size the beaumont belt is? the closest j belt i can find is a 20 rib but it's only 1.84'' wide. the belt is a 2'' width right?
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Look on his website, he sells that replacement belt.
 
mike-E said:
i probably wont use the same length and he doesn't list the actual belt number
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Oh, but he does.


all it takes is a little clickity click


http://www.beaumontmetalworks.com/shop/item.aspx?itemid=79


Item Details
Rotary Platen Belt
Item Name:
Rotary Platen Belt
Item #:
260J20
Price/ea:
$43.00


Take that number to any belt dealer like Gates or Jason

That number is not just a "part number" it's standardized nomenclature.

http://www.amazon.com/Gates-260J20-Micro-V-Section-Length/dp/B00CJK9K0U
 
yeah i went back and checked again after i posted. sorry bout that. and gates lists the j 20's at 1.84'' overall width, so are you guys tracking your abrasive to each side to grind? i could see maybe a 32nd sticking out each side but .080 could really bite into a ricasso. maybe im over thinking it?
 
Width is one inch and seven eighths


so less than that

Using a jflex belt on the plunge it curls away more than it digs in, gives you that nice radius.



You don't have to push the blade straight in, you can just come in to one side of the belt at an angle
 
When the bearings burn out can you replace them with higher quality bearings without buying a new wheel?
DR...
 
mike-E said:
yeah i went back and checked again after i posted. sorry bout that. and gates lists the j 20's at 1.84'' overall width, so are you guys tracking your abrasive to each side to grind? i could see maybe a 32nd sticking out each side but .080 could really bite into a ricasso. maybe im over thinking it?
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Yes. I track the belt to each side as I work that side's plunge.

Daniel Rohde said:
When the bearings burn out can you replace them with higher quality bearings without buying a new wheel?
DR...
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You can, but the wheel will cup itself out by then, and need replacing anyway.

Fatboy1994 said:
Anodizing the aluminum wheels might help with the cupping of the wheel.
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Hmmm. Hadn't thought of this.
 
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