advice on contact wheels

[WraithsNinja]

So I've heard of people using mfd board to make 10" contact wheels. To me laminated plywood with a pice of leather glued to the contact surface seams a little less deadly. What does the hive think?

[SpankySmith]

Forgive my total ignorance but..... what's a "contact wheel"?

[Frosty]

Forgive my total ignorance but..... what's a "contact wheel"?

 

The contact wheel on a belt grinder is intended to be used to grind against directly producing a hollow ground surface. Contact wheels are usually rubber tires on metal wheels, the visual is similar to a rubber castor on a shopping cart wheel, less the wobble of course. <grin> The rubber allows a little give behind the sanding belt to both provide better contact against the work and avoid damaging the belt.

 

I got any of that wrong I'll appreciate better info for my mental tool kit.

 

Frosty The Lucky.

[rockstar.esq]

I don't know why mdf would be any different from plywood in terms of danger.  I would imagine that mdf is probably superior to osb for that application since it's got more glued surface area.  Premium plywood would be another story but since the edge of the material is what's defining the contact area, I'd again go to MDF because it can be made much smoother with less trouble. Plus mdf's much more consistent in terms of density so the wheel would balance easier.

 

I have some commercially made laminated paper wheels on my 8" grinder that are part of a sharpening kit I got at a woodworking store.  One has grit glued to it, the other is slotted and is used with white rouge. It's very effective and stable at 1800 RPM's.