Thread: Mill vice rebuild

Be careful about using a spin test with asymetric surfaces or uneven weight distribution. It is really meaningless and may lead you to false conclusions. Trust your surface plate and blue!

Originally Posted by Ueee

The first grinding was only to get it in the ballpark, The top and bottom were not flat and not parallel.

Ew

Love it, Grinding to "rough" it in. don't forget to say "Weeeeeeeee......" as you slide down that slippery slope :P

seriously though, the flatter the surface you put against the mag chuck the better the parallel side will be, as a bend is easily taken out with the mag chuck, I'm often amazed at how little force is needed to twist/ bend metal at the 0.0001" sort of level, even thick sections will "suck" down to the chuck by more than what you might think. 0.080" bow in 12" long 3"x3" section is nothing and will be sucked flat to the chuck only to spring back when released.

I have heard of using plaster, wax and other materials to cast the part into to support it so that the mag chuck can't pull it flat. Never tried it myself.

When we first got our grinder I thought of the process more in terms of flatness operation rather than what I think of it now as a parallel operation.

-Josh

Originally Posted by Brobdingnagian

Love it, Grinding to "rough" it in. don't forget to say "Weeeeeeeee......" as you slide down that slippery slope :P

This is all i could think of when i read that....probably apt too!

Mythbusters waterslide part 4 - YouTube

A video i was watching, i think it was the Tool and Die Guy, was about electro mag chucks and bending. He turned the mag right down then slowly turned it up until the part was just being held. He reckoned it worked well. I can't try that......

On the subject of chucks, one thing i am finding annoying is the residual magnetism in the top plate after you turn the chuck off. It really holds the parts there, to the point were you have to slide them to the side of the chuck, which is scratching the freshly ground surface.

If anyone spots a 24" x 12" electro mag chuck.......

Cheers,
Ew

Oh, the vice is flat and ready for a grind. I gave up on the spin test and just went with the spotting in the end.

Originally Posted by Ueee

On the subject of chucks, one thing i am finding annoying is the residual magnetism in the top plate after you turn the chuck off. It really holds the parts there, to the point were you have to slide them to the side of the chuck, which is scratching the freshly ground surface.

even with electro-mag chuck you still have that problem with a ground surface on the chuck, it has more to do with them being wrung together and a light water seal around the part.Normally I can tilt the part of the chuck and thus save the from scratching it, but some times it is just seems impossible. If I really want to make sure I can get the part off the chuck with the surface intact I make sure to have a way to torque it off, eg a lip or hole so that I can gently apply pressure to lever it off. It is a real pain as the better the surface finish/ and flat the part the more it will stick.

-Josh