grinding on a mill

[loose nut]

Some years ago I saw a picture of a grinding attachment for a vertical mill, like a lathe tool post grinder mounted by a post in the spindle.

If protection is made to protect the mill from dust and sparks and a mag. table is mounted on the table to hold the work and allowing for the slow table traverse, with very light cuts, is this a viable idea for the odd grinding job.

Any thoughts.

[tdmidget]

Nope. What makes grinding machines different is the precision in the ways and slides. If you have Bridgeport quality ways you have Bridgeport precision regardless of what is in the spindle. If you just want it to look like it was ground then you might fool someone. Only until he checked flatness, etc.

[Guido]

Kicked the head on the Saimp way over to an indicated 45 degrees, installed a small wood router with stone in the horizontal, parallel to the table. Exhaust valves from a V6 S-10 were ground by manually reciprocataing the table under each valve held by the slowly rotating mill spindle. Mill head was repositioned and the intakes ground.

Visually, the ground surfaces looked equal to a new aftermarket valve. Manually lapped each valve into a newly ground seat and all was good. YMMV

--G

[tdmidget]

Kicked the head on the Saimp way over to an indicated 45 degrees, installed a small wood router with stone in the horizontal, parallel to the table. Exhaust valves from a V6 S-10 were ground by manually reciprocataing the table under each valve held by the slowly rotating mill spindle. Mill head was repositioned and the intakes ground.

Visually, the ground surfaces looked equal to a new aftermarket valve. Manually lapped each valve into a newly ground seat and all was good. YMMV

--G

Means nothing. Automotive quality work is not impressive. That's why you had to lap them.

[flathead4]

allowing for the slow table traverse, with very light cuts

Not an expert, but I think that is the opposite of what you want. I think if you take slow cuts you will cause your work to heat up and depending on the material, end up with a banana. Check out some youtube videos of surface grinders in operation and see how fast they move.

[Evan]

Automotive parts are made to within microns in many cases.

Grinding on a mill is very viable, I do it regularly. Since my mill has hardened round rod ways they are very easy to replace although it hasn't been necessary yet.

[strokersix]

Whether this is appropriate depends on your objective I think.

Precision flatness, get under oxide skin, grind thru hard spots, make pretty, production quantities or single, cylindrical or flat, etc. are all different objectives.

Reciprocating speed could be increased by disconnecting the lead screw and manually moving the table.

[loose nut]

Not an expert, but I think that is the opposite of what you want. I think if you take slow cuts you will cause your work to heat up and depending on the material, end up with a banana. Check out some youtube videos of surface grinders in operation and see how fast they move.

I was referring to the limitations on the table travel feed which is much slower than a surface grinder.

This was just a thought for the vary rare times (hobby use only) that I might have a need for it, which doesn't justify the expense of buying a real grinder even if I could afford it. Obviously surface finish would not be up to that of a "real" grinder, but tool post grinders are used on lathes, with acceptable results (but less then a cylindrical or universal T & C grinder) and the same limitations are present.

[tdmidget]

Automotive parts are made to within microns in many cases.

Grinding on a mill is very viable, I do it regularly. Since my mill has hardened round rod ways they are very easy to replace although it hasn't been necessary yet.

You are absolutely right. OEMs routinely produce many parts to such tolerances.
But Billy Bobs Auto Machine certainly does not repair them to anywhere near those tolerances.

[Arcane]

I've done a bit of grinding on my BP clone mill with good results. I do it when the material is too hard to turn in the lathe or I want to sharpen something to an exact angle since I don't have a good way of doing that on a benchtop grinder.