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Aluminum t slot nuts?

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DiscoDan

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#1
Everything I see online is steel. Will aluminum (6061) not hold up? Thinking of making my own for my Pratt & Whitney 3C. I can buy 3/8" nuts online but one thing I don't like is that the width of those nuts is 5/8" and my width can be 7/8" and I would like to take advantage of the full width.
 

T Bredehoft

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#2
The width won't be the problem, the threads will eventually pull out.
 

Downunder Bob

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#3
At least with aluminium "T" nuts you'r unlikely to damage the "T" slots in the table.
 

rwm

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#4
I just made a bunch out of mild steel on my lathe. Very easy. I agree that the threads will fail in aluminum.
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Robert
 

Bob Korves

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#5
I also prefer mild steel. Strong enough, yet will not damage the t-slots if all the edges and corners are well rounded, not just lightly deburred. They are cheap to make, and can be made to the clearances you personally want. Make the threads so they do not let the bolts go through the bottom of them, or damage the bottom of the thread with a cold chisel. Protecting the t-slots from damage is important. Make sure that when you pull up on the finished nuts, the top surfaces are still adequately below the table top, otherwise they will not tighten in the slots and will slip. Swarf can also cause a problem of the t-nuts slipping in the slots if that tolerance is too close, I prefer the t-nut tops about .030" below the table top (or more) when pulled up.
 

JimDawson

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#6
A Heli-Coil would make the threads almost permanent
 

benmychree

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#7
It would be time wasted to make aluminum nuts, they would not hold up, stripping threads being the problem, they would also imbed chips, causing roughening of the slots; mild steel is fine, alloy steel even better, case hardened, even better than that, as most purchased tee nuts are, at least the quality ones.
 

samstu

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#8
I don't disagree with what has been said above by experts. However, some people do successfully use aluminum t nuts.

See "Chirpy's Tinkerings" on youtube. www.youtube.com/channel/UCYCuE8KFwaIgG76kPTVR5jA/featured This guy makes and uses aluminum t nuts. He also casts and uses machine vises, dividing heads, tools out of aluminum. Maybe not a study in best practices, but does show what can be done with limited expenditures and some thought. I especially recommend his video on making v blocks.
 

P. Waller

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#9
Why not make them from aluminum?
If a hobbyist it is unlikely that you are clamping multiple parts every day for weeks, months or years.
When they fail replace them, in the long run it is likely more cost effective to buy inexpensive steel nuts then it will ever be to make them.
 

ThinWoodsman

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#10
I made some aluminum T-nuts for use on the Taig mill. Haven't had any problems. Only real downside is you have to use coarse threads .
 

rwm

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#11
Here's my thinking. If you plan on making these, all the effort is in the time it takes to do so. So if you are going to spend the time, at least use the best material. 12L14 steel is cheap and is not much more difficult to machine than aluminum. I guess if all you have on hand is aluminum then go for it! I agree it would be cheaper to just order some but....
Robert
 

BaronJ

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#12
I made some aluminum T-nuts for use on the Taig mill. Haven't had any problems. Only real downside is you have to use coarse threads .
The reason for coarse threads is to reduce pull out and thread stripping.
 

DiscoDan

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#13
I have the aluminum so I might try it. Won't hurt anything. I may buy some steel ones too "just in case."
 

whitmore

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#14
A Heli-Coil would make the threads almost permanent
That's a good protection against the threads accumulating damage. Also durable, and cheap and easy to produce in the
shop, would be a shouldered threaded insert.
I can't imagine that the shoulder-seat strength would be a problem, even weak aluminum makes a good socket support.

An aluminum TEE would be nicely grabby at the internal slot surfaces.
 

BROCKWOOD

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#15
I bought a box of 50 T Nuts for pennies on the dollar compared to making them. We're here because it is just a hobby. You choose how you make chips & for what purpose!
 

BtoVin83

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#16
It's all about application. If you plan on machining tank gun turrets aluminum may not be the best choice. If making watch parts you probably can get away with it.
 

mikey

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#17
Dan, I would use 7075 instead of 6061 but it will work fine. 7075 is pretty close in comparison to many mild steels in terms of strength and machines similarly, too. Cost is higher but it is light, strong and makes good T-nuts. While I agree that just buying them is cheaper and easier in most cases, sometimes you need a specific size that is hard to find, and sometimes you just want to make your own so I would go for it.

I have some 7075 T-nuts that I made over 20 years ago and they're as good as the day I made them. Caught some flack on "another forum" for using aluminum but they were a lot better than the cheap Chinese "unknownium steel" stuff you can buy today.
 

Downunder Bob

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#18
I'm sure aluminium will work well for occasional light duty. For hobbyists it often comes back to cost. So for me I would use steel because i can get plentiful offcuts in various sizes for free, whereas I have to pay full tote odds for aluminium
 

MarkDavis

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#19
I made some from aluminum. Right after buying my mill, buying any thing else was out of the question for a while.
Had aluminum on hand.
They were made so a bolt slipped through them, with the head down and threads up.
The bottom of the T-nut is counter sunk with enough interference to keep the hex head snug.
 

DiscoDan

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#20
I appreciate all of the comments. I ordered some of the steel nuts since they are so cheap but I think I will make some out of aluminum anyway, partly to have around but also to practice using my P&W milling machine. One thing about the steel nuts is that the widest part of the T in my table is 7/8" but the nuts that fit my 7/16" slot are usually 5/8" or 11/16", which will let the nut turn slightly in the slot and "may" do some damage over time. Custom nuts would provide a tighter fit. On the up-side, I did finish the new draw-bar assembly to adapt the R8 collets to my machine in place of the unobtainium 4pn collets. The R8s have dimensions very close to the 4pn but use a draw-bar instead of the 4pn draw tube. So I lose the ability to work on longer pieces through the collet but I really didn't have much choice.
 

Bob Korves

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#21
One thing about the steel nuts is that the widest part of the T in my table is 7/8" but the nuts that fit my 7/16" slot are usually 5/8" or 11/16", which will let the nut turn slightly in the slot and "may" do some damage over time.
Probably the best reason for making your own t-nuts is protecting the t-slots from damage. They are an important part of the precision of the machine. If you have hardened t-nuts with sharp corners and burrs, they will tear up your t-slots. Not as visible or embarrassing as top of the table damage, but probably worse for turning out accurate work. A nice fitting t-slot cleaner tool that does not gouge the slots is also a wonderful thing. Again, easy and cheap or free to make. I find I do better work with tooling I made myself, helps to change my attitude from slam-bam git-er-dun to a "I'm in no real hurry" happy smile.
 

Winegrower

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#22
Echoing Bob Korves, i think it’s important to damage the lowest thread on the t-nut so that the stud does not run through the nut and press on the bottom of the table slot. This of course could really distort the table if you were wrenching hard to hold down a part and didn’t notice what was happening. A good argument against aluminum is that it’s unlikely to resist much torquing with a single damaged thread...the rod will just reform the t-nut thread.
 

rwm

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#23
Very interesting discussion all. I will have to go back and damage the bottom threads on my T nuts.
Thanks
Robert
 

ttabbal

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#24
I've only made a couple, but I just didn't run the tap all the way through. Mine were steel.
 
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