[gogego]

We have a case hardend, ground shaft with a V-slot.
We then put through hardend "spacers" on this shaft then grind the OD of these "spacers".
As long as he spacers aren't moved there is no problem, but if there is an adjustment made to the location of a spacer we occasionally find runout problems.
I am convinced it is caused by inconsistant bore size, and because we don't have an ID grinder we need to find a way to reduce/eliminate runout when "spacers" are moved, replaced, or repaired.
It has been suggested to add a hub with perpendicular intersecting saw cuts
and a threaded hole to clamp the "spacer" to he shaft.
Do you think his would help?
Any thoughts appreciated.
CHEERS!

[RICHARD ZASTROW]

Sounds like what an associate of mine referred to as "a stack of donuts".

If the hole has any clearance, the workpiece will rest against the shaft creating an O.D. that's not concentric to the I.D. by the amount of the clearance.

Added to that, if the O.D. of the shaft the "donuts" are mounted on has any run-out, it will compound the problem.

Then there is the potential of the shaft bowing from tailstock pressure or ??????. That would compound the compound.LOL

Depending on tolerances of the "donuts" and the mounting shaft, the problem can probably be reduced to acceptable limits. I doubt it can be eliminated completely to produce a perfect "stack of donuts".

Dick Z

[gogego]

Another thing I should mention, the "spacers" can have a thk. around .31"
Maybe 3 eq spaced V slots on the shaft and 3 set screws on the "spacers" but we can't always pull that off w/o interfering with a part feature, along with the extra time...gotta kiss! just need to nail the ID:stickpoke
CHEERS!

[RICHARD ZASTROW]

Could you finish the spacer I.D. after hardening? Maybe honing to finish size then finish the O.D.?

Dick Z

[gogego]

We do finish the ID after heat treat. We leave about .01" stock the turn it to size, :bs: we dont have an ID grinder or hone, then they are assembled, ground, QC'd, shipped....however we don't disassemble then reassemble them to insure this degree of quality:idea: ....time to test the donuts.
CHEERS!

[RICHARD ZASTROW]

Or finish bore I.D. with ceramic tool?

In a past life, we made a gazillion hardened rollers. After hardening, the I.D. .500" bore was finished with an abrasive tool similar to those diamond bore sizing tools you see advertised. (Engis I believe) Ours were not diamond though and CBN wasn't invented yet.LOL

They held size well. After that, they were mounted on a mandrel (stack of donuts) and the 1.500" O.D. were finish ground. Worked fine.

Dick Z