workholding on a GR408 w/ drilled alum. table

[kendo]

I'm used to milling on a table with t-slots,
now we just got a new GR408 with the aluminum table drilled and tapped on 4" centers

8" is too wide for my kurt vises to bolt right down,
so I was wondering what are some of you guys' favorite methods on a table like this

adapter plates?
locating pins?

I use ground keys on the vise bottoms that engage the t-slots saving me the time of indicating, what kind of tricks like this do you use on the drilled table?

If I use locator pins that slip fit into the table, should I use bushings in the alumimum?

[Geof]

For locator pins I suggest using steel bushings in the table.

Also if you are going to be taking the vises off frequently I suggest drilling and tapping holes on the bolt pattern that Kurt vise and Helicoil the threads. The aluminum thread will fatigue and strip fairly soon, not to mention if you wrench too hard you will strip it.

On my GR510 I tapped the table 9/16" NF on a 4" grid then screwed in steel inserts with a 3/8-16 internal thread. The inserts have a flange that fits in a shallow counterbore around the 9/16" thread and are locked in with small setscrews. This way damaged inserts can be removed and replaced.

[kendo]

thanks Geof, I got some inserts on the way
and I'm gonna bore the table for a matrix of pin bushings for part alignment

as for the pins, I've been told that a slip fit in the table and in the fixture would suffice, then I was told one or the other should be a press fit
what do the majority of you guys do?

I would think you'd rather not have pins pressed into your table OR your fixtures/vises.

BTW do very many of you bore the bottom of your vises for locator pins?

[Geof]

Originally Posted by kendo ...as for the pins, I've been told that a slip fit in the table and in the fixture would suffice, then I was told one or the other should be a press fit...

The bushing in the table should be a press fit but I don't see the need to have the pins a press fit in either vise or table. If you do make them a slight press you should tap a thread in the end for extracting them again.

As far as boring alignment holes in the vises some already have them. I have no hang up with boring alignment holes in the vise; but then I don't have any hang up about boring alignment pin holes in the machine table if I need them. And doesn't this create howls of anguish from some people.