any suggestions for contact wheel form?

J

Jared Stenoien

Joined
Dec 4, 2005
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i have the chance to use the lathe cnc machine at a machine shop but the owner wants me to draw out the design, i am making a contact wheel but i am also making it with a bevelled face on one side for a disk sander, this is a picture of half the cross section. any improvements? speciffically i am interested in the crown on the outside, it is a .05"x.5" chamfer with the corners rounded. if you'd like to look at the actual .dxf file i'd be happy to email it to you. thanks :D

contactwheel.jpg
 
Wouldn't you want the face of your contact wheel flat? The taper out to the edges is gonna raise hell hith your grind.
 
The contact wheel is flat, either the drive wheel or idiler pully will have a slight crown , the reason is to enable tracking (being able to control the belt to keep it centered on the wheel and also allowing to drift the belt slightly over the edge of the wheel .
 
I also misunderstood the crown thing and made my wheel profile similar to what you show there. It was impossible to grind with it. Okay, I was new to the game but still....
Turned out that what the fellow meant was that you just put a small radius on each end of the wheel, about 0.050" to 0.060" to help you get the radius at the end of the grind at the ricasso side. The belt can also tend to lift fractionally on the ends and cause drag marks. Maybe everyone will not agree but I think it is better to have a small radius on the edges of the wheel.

Mike
 
I know a heavy belt wont bend that tight on such a small radius. Try a grind with the belt hanging over just a little and it cuts sideways into where you started your grind. That radius might work with a light trizac belt. I'de stick with tried and true. What's the point of the edge bevel?
 
RUJOKO, yes, of course I meant to add that you have to hang the belt over a bit too. The radius does help along with the overhang.
True, the coarser grits are less flexable. A guy showed me though that you hang the belt over a bit and you "kill" the sharpness of the belt a bit with a piece of scrap steel, this also helps to take the shape of radius. I normally do that with a 180 grit or finer.
Some other guys have posted similar threads here too.
Anyhow, to each his own, it works for me.

Mike
 
I was just wondering why you would need a radius on the wheel becuase I never radius my grind till the the end. This gives me a tight radius instead of a long(relatively) tapered radius. I personally want that belt to grind off as much as it can, fast and accurate. But....you're right, to each his own. If it works for you, who can argue with that.
 
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