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View Full Version : Belt sander modification advice needed....



x39
06-16-2004, 11:08 PM
I have a Taiwanese combination belt sander/grinder. The contact wheel on the belt sander part of it has a rubber tire that has somewhat rounded corners. I'm thinking about making an aluminum contact wheel, with no tire on it with the idea of being able to more accurately off hand grind things. Would the lack of cushioning a tire provides cause problems? Thanks.

Dave Opincarne
06-16-2004, 11:14 PM
Belt sander racing right http://bbs.homeshopmachinist.net//wink.gif

Is this a stationary unit or a hand held? I've seen aluminum drums on some hand held belt sanders so it should work. Are the drums fixed or do they ride on springs? I'd be less certain if the drum is ridged.

sandman2234
06-17-2004, 12:39 AM
Wondering if the curvature is the crown that keeps the belt on... like the leather belt that drives my Southbend...the pulleys have a crown in them.
David from jax

Dave Opincarne
06-17-2004, 12:45 AM
All the ones I've seen seam to have them, but that wouldn't be hard.

[This message has been edited by Dave Opincarne (edited 06-17-2004).]

gizmo2
06-17-2004, 12:53 AM
X, I just made new wheels this winter for my old Rockwell 1". The rubber tires dried up and cracked off years ago, and the plastic wheels finally gave up the ghost. I crowned only the wheel with the tracking adjuster, and left the drive wheel flat. Then they aren't fighting one another as to who wears the pants in the tracking family.

NAMPeters
06-17-2004, 12:56 AM
If there is a platen behind the sanding belt then don't worry about it. If you replace the pully then the replacement needs a crown to track the belt, just like any flat belting. The amount of crowning would be open to experimemtation IMHO.

------------------
Neil Peters

Dave Opincarne
06-17-2004, 01:05 AM
Why does the presence of a platen detrmine wether crown is needed?

x39
06-17-2004, 07:17 AM
Just to clarify, this is a bench mounted unit. I intend to grind on the periphery of the wheel (an attempt at hollow grinding knife blades).

wierdscience
06-17-2004, 07:46 AM
without the cushion effect of the rubber you may get some bounce and you will kill abrasives fast.

Bill Cook
06-17-2004, 07:47 AM
It'll work fine.

If it is also the drive wheel, don't finnish it too smoothly. What looked like a fine torn thread worked really well on a sander I got to know very well. And it didn't tend to screw the belt off. ©=©

bc

[This message has been edited by Bill Cook (edited 06-17-2004).]

Toolbert
06-17-2004, 01:13 PM
The biggest problem working right on the wheel will be finding belts that don't have a big bump at the joint. Joined end-to-end with tape instead of overlapped and glued.

I believe only one of the wheels needs to be crowned.

You might be better off just making a better platen, or if you need the curvature then adding another wheel in place of the platen.

Bob

darryl
06-17-2004, 03:57 PM
It's also possible to coat the drum with tool-kote, then turn it on the lathe to grind the rubber surface to an accurate dimension, using a tool post grinder or similar. It's messy, but it works. If you need the grippy surface to drive the belt, this is one good way to do it. You could use shoo goo instead of tool-kote, it's a pretty durable compound and also grinds well. Rough up the drum really well before application so there's a good tooth to hold the coating.
Multiple coats will be required to build up thickness before grinding. Tool-kote handles this well, but I'm not sure about the shoo-goo. It might like a roughing up before successive coats.

[This message has been edited by darryl (edited 06-17-2004).]

x39
06-17-2004, 05:22 PM
Thanks for all the input guys. I think what I'm going to do is make the contact wheel as I first planned using just metal. If the results are unsatisfactory, I will turn the OD down and coat it as described above. Thanks again!

Ted Coffey
06-17-2004, 05:23 PM
The rubber wheel is the drive wheel. If you use metal wheel with its small diameter the belt will slip. Also the rubber wheel provides cushioning of a "Contact" wheel. If you rough up the metal it will work for sometime but will eventually smoothout. I have a large Belt stationary sander with smooth metal wheels but there diameter is around 5" which gives enough surface area to provide the traction.

wierdscience
06-17-2004, 10:00 PM
Oh forgot to mention,you really don't need two wheels,just a crowned drive pulley and a curved platen covered in graphite cloth.