T Nuts: What if any treatment?

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T Nuts: What if any treatment?

This topic has 22 replies, 15 voices, and was last updated 8 July 2017 at 22:57 by John Haine.

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5 July 2017 at 18:12 #305688
Nige
Participant
@nige81730
Looking to make my own T Nuts and wondering if they are just plain mild steel or are they hardened/tempered please?
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5 July 2017 at 18:12 #29722
Nige
Participant
@nige81730
5 July 2017 at 18:15 #305690
Vic
Participant
@vic
I've made T Nuts for a couple of mills over the years out of plain mild steel. Not heard of anyone hardening them before but you could do I suppose if you wanted to.
5 July 2017 at 18:21 #305691
Nige
Participant
@nige81730
Thanks Vic, I don't want to harden them, plain mild steel is ok by me if that's the usual
5 July 2017 at 18:28 #305694
John Haine
Participant
@johnhaine32865
If you tighten them enough for hardening to help, they will be too tight!

However, when I made some out of some square BMS bar, I started by milling down one dimension to suit, and when I took it out of the vice it had developed a banana-like bend due to stress relief! So you may find it a good idea (if you use BMS) to get it red hot for a minute or two and let it cool slowly before starting to machine it. Or use black bar.
5 July 2017 at 18:37 #305698
Nige
Participant
@nige81730
Thanks John. I have heard of BMS 'unstressing' when it is machined, Ill try for black bar when I come to it
5 July 2017 at 19:43 #305708
steamdave
Participant
@steamdave
Posted by Nige on 05/07/2017 18:37:45:

Thanks John. I have heard of BMS 'unstressing' when it is machined, Ill try for black bar when I come to it

And bash the bottom thread with the ball of a hammer to deliberately damage it so that you can't run the bolt all the way through and possibly damage the slot.

Dave
The Emerald Isle
5 July 2017 at 20:09 #305714
AJW
Participant
@ajw
I tend to used a variety of studs in T nuts then run a washer and but on.

Alan
5 July 2017 at 21:12 #305741
Roger Provins 2
Participant
@rogerprovins2
Made a handful by milling two corners of a strip of mild steel then chopped it into short lengths and drilled and tapped them.

Edited By Roger Provins 2 on 05/07/2017 21:13:19
5 July 2017 at 22:34 #305767
Mark Rand
Participant
@markrand96270
If you make T nuts of the small size needed for Myford lathes and such, then hardening them can be useful to avoid thread tearout. I ended up case hardening all but one of the ones I made. Tthe other one didn't have any threads left…
6 July 2017 at 00:16 #305777
Hopper
Participant
@hopper
I make my own, Myford size, and never harden them. No problems.
6 July 2017 at 01:28 #305778
Enough!
Participant
@enough
Posted by Nige on 05/07/2017 18:12:21:

Looking to make my own T Nuts

Don't forget that you can turn T-Nuts if it's more convenient – stepped diameters; drill/tap; cut off; then mill flats on the larger dia. I generally find it less fiddly. Probably gets around any BMS distortion issue too.

If you don't mind interrupted cuts, you can even put flats on a length of bar, turn the barrel dia and part/saw off. Repeat as necessary.

Edited By Bandersnatch on 06/07/2017 01:28:51
6 July 2017 at 08:27 #305792
not done it yet
Participant
@notdoneityet
I have a dozen in a row at the moment, machined, drilled and tapped, waiting to be cut into separate pieces.

A dozen because my mill only has 12 1/2" traverse and they will be milled to ~22mm long (if the cuts are all square). There will be more as both mills use the same 3/8" size.

I would have preferred a hardenable steel as the threads would be less likely to get damaged (tight studding in the threads is a bear), but these are from black iron bar and I am likely not going to case harden them (my wife complains when I use the kiln for hours on end – no, every time I use it, if she knows!).
6 July 2017 at 08:40 #305793
Chris Evans 6
Participant
@chrisevans6
If you use studs and not bolts in to the tee nut the life of simple mild steel will outlast you.
6 July 2017 at 11:42 #305835
Mark Rand
Participant
@markrand96270
Posted by Hopper on 06/07/2017 00:16:55:

I make my own, Myford size, and never harden them. No problems.

Do you use 1/4" or 5/16" threads? I use 5/16" and there isn't much meat left on the top part of the nut at that diameter.
6 July 2017 at 12:24 #305844
Neil Lickfold
Participant
@neillickfold44316
I leave T nuts soft. I don't want them harder than the bed or slide they are being used on. If they wear over time, just replace or use helicoils to recover the threads. I make them fairly long to spread the load over the most area that is reasonably possible. Neil
6 July 2017 at 12:35 #305845
Martin Kyte
Participant
@martinkyte99762
This site gives a clamp load of 700 odd pounds for a 1/4 inch bolt.

**LINK**

Myford boring tables are a little on the slender side so gently does it. Milling tables are much more robust.

regards Martin
6 July 2017 at 13:47 #305856
Mick B1
Participant
@mickb1
All the industrial T-nuts I've used have been as hard as a landlord's heart. When I wanted to shorten one by a few thou to stop it projecting proud of the table and defeating a clamp, I had no option but to grind it.

I'd imagine gauge plate would probably work well unhardened for most ME uses, but I think you might need to remake MS ones quite often.

Edited By Mick Burmeister 1 on 06/07/2017 13:49:15
6 July 2017 at 14:03 #305859
Vic
Participant
@vic
Posted by Bandersnatch

Don't forget that you can turn T-Nuts if it's more convenient – stepped diameters; drill/tap; cut off; then mill flats on the larger dia. I generally find it less fiddly. Probably gets around any BMS distortion issue too.

Yes, I've made them like that as well.
6 July 2017 at 14:39 #305867
Enough!
Participant
@enough
I have to admit that I only ever make the "specials". I buy standard T-Nuts …. they are so inexpensive and I have more than enough jobs in progress and planned that the time can be better spent on.

Most of the ones I buy don't seem to be particularly hard. At least I've milled/filed them down for other purposes occasionally.

Edited By Bandersnatch on 06/07/2017 14:40:51
6 July 2017 at 20:01 #305926
Nige
Participant
@nige81730
Resigned to having to make T Nuts as I am finding it difficult to find them to fit my Myford ML4; all the commercially available 3/8 threaded ones seem to be too deep in the base as the bottom slot is only 5/32 'thick'. 8mm versions seem to have the same problem.
8 July 2017 at 21:41 #306213
Howard Lewis
Participant
@howardlewis46836
Have never found mild steel to be a problem, either T section nuts, or a thinner disc with two flats, in the bottom of the slots. Have made lots.

After all the forces that you can generate with a 1/4 BSF or M6 will crack a Myford Cross slide (Anyone want the T shirt?) M8 and M10, being coarser pitch, are less likely to damage the table on a mill.

Ideally the nut should be just a few thou below the surface when pulled upwards, so that any distortion is minimal, and less than that to crack the material.

Howard
8 July 2017 at 22:57 #306229
John Haine
Participant
@johnhaine32865
My sense is that I never tighten Tee nuts/bolts/studs to anywhere near the point where a non-hardened thread is likely to strip; and if you are doing that then it's much too tight. And I've not had things moving on the mill table either.
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