Question about T Slot hardware

Another question: what do you guys use for indicating where to put your vice and such?

I was thinking of making some T-nuts with just a low profile setscrew and a locating hole sort of like the tormach ones, but was wondering if there is a better way.
 
Just read this post and it has not been mentioned yet. I would be very careful about what you stick into the “T” slot. And I mean size wise. You can damage the T slot in the table with a poor fitting nut/bolt. The previous owner of my Bridgeport used poorly fitting hardware and made a nasty burr on the underside of the table T slots. It wasn’t easy to fix…Dave
 
I'm with Dave/Chips, I've seen a lot of tee slots with the top broken out, it's one of the saddest sights there is, up with oil-soaked kittens :(

I've always taken a hammer and chisel to the bottom of the nut's thread to damage it so the bolt/stud can't pass through and jack the nut up and break the "ears" of the slot, they're supposed to be in compression between the tee nut and the attached vice/work/whatever, cast iron's a lot stronger in compression than tension or shear...

To locate the vice etc. you can slot the bottom faces for a key that's a good close fit in the tee slot, ideally two slots at 90 degrees to allow you to set up with e.g. the jaws parallel with either X or Y, it'll be repeatable if you're careful and get a good/tight fit in the tee slot (when you can clamp the upside-down vice's jaws on the key and hence know they're parallel with the tee slot, then use clamps to hold it down while milling the vice-bottom slot. This assumes the tee slots are really parallel with the X-axis movement, YMMV...)

Dave H. (the other one)
 
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OH, also - when using tee nuts with anything that *doesn't* clamp down on the top of the table (e.g. http://3.imimg.com/data3/CH/ED/MY-2291399/1-250x250.jpg), I run a flanged/washer-and- nut down before the rest of the hardware so the slot's clamped between it and the tee nut - SO FAR (knocks on wood, injures head) I haven't broken a tee slot! Remember that the stud in the tee nut has the sum of the downward forces on work and e.g. step block pulling UP on it! Also, it gives (I think) a more rigid setup.

Dave H. (the other one)
 
Dave makes a good point about running a nut down to pinch the table top. I've never done that, and with the components supplied in a regular clamp kit, you cannot. But it does make sense. I've never damaged a T-slot, so I suspect the extra measure is not necessary- still a good point to raise.

About the alignment keys under a vise. I don't think they should be a tight fit in the slot. The edge of the keys should be parallel to the fixed jaw. Just push the vise/keys against the slot and tighten the nuts. Push it so the cutting direction is pushing th keys against the slot. I suppose snug keys would hold a little better? However, when those two good size bolts/studs are tight, it really ought not move.

Another Dave
 
A quick and dirty way to make larger T slot hardware like found in a compound slide is to just weld 2 hunks of steel together. DSC_0900.JPGDSC_0901.JPG
 
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