Power tapping test results

[Vinny]

I tapped thru but never run the screws that far thru. I like them to be able to move while I'm positioning things. If at any time I find I'm even getting that far in I'll screw up the bottom few threads. I'm actually good at screwing up threads!

[Mayhem]

I think the issue is that the bolt can bottom out when the nut is being tightened.

[Vinny]

Yeah, I'm aware of that but since I have a very limited supply of 3/8-16 anything it's rarely long enough to get all the way thru the nut, let alone to the bottom of the slot. Eventually I'll make a bunch of threaded rods and make the thread on the side that will go into the nut shorter. I did that on my screwless vise when the original fell apart (worthless pressed fit).

[f350ca]

My commercial T-nuts just have two chisel marks on the bottom thread, works fine.

[EdK]

Ed

[PixMan]

Not my top-quality Te-Co products, in both the 3/8-16 and 1/2-13 sets. Full threads down to about 1-1/2 to 2 turns before they'd break through.

[Vinny]

For the record, I did smash a couple of threads with a punch tonite, then screwed a 3/8-16 into it. There was a little resistance and then it cleaned up the threads. Guess I need to try a different tool.

[f350ca]

Just for argument sake. (we all like those).
I've heard the story of the stud bottoming out and while tightening the nut it jacks the T-nut up and breaks a chunk out of the table. Maybe we could get Myth Busters involved. I'll give you that when your bolting down a vice the table is totally in compression between the T-nut and the base of the vice. BUT when you use the straps that come in the clamping kit the stud with T-nut on the bottom is pulling the same tensile force on the table (with nothing directly above it) as the bottomed out stud does.

[Vinny]

Well if its all the same to you guys, I don't wanna be that guinea pig.

[Dr Stan]

(04-06-2015, 09:06 PM)Vinny Wrote: For the record, I did smash a couple of threads with a punch tonite, then screwed a 3/8-16 into it.  There was a little resistance and then it cleaned up the threads.  Guess I need to try a different tool.

Try using a ball bearing to purposefully roll over the bottom thread.