Buerste wrote:

"Tim Wescott" wrote in message
...
On 08/11/2010 12:36 AM, Buerste wrote:
"Gunner wrote in message
...
On Wed, 11 Aug 2010 01:57:58 -0400,
wrote:


"Gunner wrote in message
...
Ive made 6 pairs of spacers...between a driven shaft (both ends) and a
bearing race and each and every time, Ive gotten the OD wrong.
Each and every time..tap on the bearing race..and the ******* slides
on.

How the hell does one calculate such a thingy?

This was off a pumping unit gearbox..and the people are starting to
look
at me like im an utter bumpkin...which it looks like I am...sigh.

The ID was to have a .002" interference fit..and I accomplished this
with no issues. I machined the OD to be .003 larger than the ID of
the
bearing race....and once the bearing race was tapped a couple
times..the
damned thing slid on with a tad bit more than hand pressure. Easy with
a
small block of wood.

Blink blink....

This doesn't make sense. Are you measuring correctly? Is the inner
race
cracked? Or, I'm not seeing the issue, re-explain it. (I often cheat
with
some .001" brass foil.)

I know it doesnt make sense. And yes..Im measuring correctly and
machining correctly.

So what is the formula?

I like the brass foil idea. Hell..I told them that Id give it a couple
tiny shots with the TIG, so it would be removable years later when it
needed to be serviced again...no dice.

My 2 hour bill has turned into an unpaid 12 hours so far. Granted..Im
learning lots of stuff...Id like to learn how to do it properly

Gunner


Sorry dude, you're NOT measuring correctly. Telescoping gauges are very
tricky and somewhat subjective. Turn a piece of scrap until you get the
fit
you want then turn your piece to those numbers.

Is that the pro machinists advice to pro machinists, or the pro machinists
advice to pikers?

It's what I do -- that, or I leave a bit of extra length on the end of the
piece I'm turning, use that to establish the fit, then once I find it I
turn that diameter all the way down, and trim off the excess length.

This works for everything from a running fit to a light press fit (if the
piece I'm fitting to isn't bell mouthed, in which case the fit turns into
an "oh ****" press fit).

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" was written for you.
See details at http://www.wescottdesign.com/actfes/actfes.html

All the universe is a kludge!


Um, no. Only in Cleavland. ;-)