T-slot sizes on a milling table

D

DMY

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A few months ago I picked up an old Cincinnati vertical mill. I have it up and running, and I now want to buy a clamp kit. I measured the T-slots on my table and got these numbers:

Width at top of T-slot: .5580" - this is just slightly less than 9/16"
Width at bottom of T-slot: .9665 - this comes out to about 31/32"

There are three sets I am looking at from Enco.

1/2" Slot size, 3/8" studs:
http://www.use-enco.com/CGI/INSRIT?PMAKA=400-2501&PMPXNO=951285&PARTPG=INLMK32

9/16" Slot size, 3/8" studs:
http://www.use-enco.com/CGI/INSRIT?PMAKA=240-7207&PMPXNO=949786&PARTPG=INLMK32

9/16" Slot size, 1/2" studs:
http://www.use-enco.com/CGI/INSRIT?PMAKA=400-2562&PMPXNO=1645538&PARTPG=INLMK32

Which one should I buy? From what I can tell, my T-slots measure slightly less than 9/16" - does that mean I can only use the 1/2" Slot, 3/8" stud set? That makes sense to me, but I want to make sure. After all, a wood 2x4 does not measure 2" x 4". Maybe there's some sort of "nominal" T-slot measurement system that I'm not aware of.
 
You may want to verify the slot size. Unless someone recut them they should be a common size(1/2", 9/16" or 5/8"). Take flat file and run it down both sides of the slots to remove any burrs or mushrooming.
 
As stated, you probably have 9/16 slots with burrs giving you the odd size. With that being said, it would be a good idea to go with the T-nuts that use the 1/2 inch studs.
 
Thanks for the info guys. The machine is from the 1940's - I don't know much about it's life. It's a production mill, and who knows, it might have been remachined.

cincimill01.jpg

I measured the slot with a digital caliper. That's really the only "precision" measuring tool I have at this time.

Maybe I can contact TE-CO and see how far undersized their slots are. Do I want a close fit, or should the T-nut readily float around inside the slot?

I'll take another look at the condition of the slots. I did not see any obvious defects, and measured the top portion rather than the bottom portion of the slots. There is a fine layer of fried baked-on oil residue, but I don't think it's making much of a difference when measuring.
 
You could take a new condition 3/8-16 (or -24) hex nut, which uses a 9/16" wrench and see if it goes in the slot anywhere on any of the slots, particularly near the end where damage would be minimal.

I just measured a random sample of about 10 tee nuts that are for a 5/8" slot and they measured between 0.590 and 0.610, so it seems likely that the slot width could and probably should be pretty close to its nominal size and the clearance is designed into the nut.
 
I would get the 9/16" x 1/2" set. And if the t nuts are to tight, well you have the tool to fix that.:roflmao:
 
Thanks guys! I can't believe I forgot to check the manual! After all, I'm the one that sent it to Shayne! (You're welcome, Shayne! :)))
 
One other question - are the clamping kits I pictured a good place to start? I don't have any work holding stuff except for a vise.

Again, thanks to everyone that replied!
 
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