# T-nut machining question



## cdhknives (Sep 10, 2014)

I got a Phase II AXA wedge toolholder from Enco, and it arrived yesterday.  First thing was to machine the T nut.

The nut included is way oversize for my 10F.  Do y'all recommend machining down the supplied nut or starting anew?  I can think of several ways to start over, but just trying to get the square nut to round is a hammering interrupted cut and holding the nut tight enough to take a decent cut was impossible.  After an hour I had maybe 1/4" turned off the corners and quit for the night.  There has got to be an easier way!

The only way I could see offhand to hold the nut was to put the new toolholder shaft in the chuck, spin on the bottom 'nut' and torque the top nut onto it.  Anything but a very light (.005" advance, slowest feedrate, about 240 RPM) cut and I couldn't get the chuck to hold tight enough and it would catch and slip.

I can see finding a high strength bolt and and machining the head off to fit the cross slide slot, but that may not be less work.

I have some 3/8" 416SS barstock, but I don't know about the strength or cutting internal threading.  I doubt I have a tap for it, and have never tried to cut internal threads on my lathe.

What's the recommended path forward to get the t nut machined?


----------



## NightWing (Sep 10, 2014)

Do you have a mill?


----------



## bedwards (Sep 10, 2014)

If you don't have a mill, you will have to find someone to machine it to your compound specks for you.


bedwards


----------



## SEK_22Hornet (Sep 10, 2014)

Do you have a 4 jaw chuck large enough to grip the plate? Or a face plate that you could clamp it to? Those would be other ways to hold it. Otherwise you might be able to clamp the plate to your cross slide parallel to the face of the chuck using an angle plate or a piece of heavy angle iron and chuck an end mill into the chuck (or better yet a collet, if you have one) and make your cuts using the lathe as a makeshift mill. If there is way too much to machine off, you may be better off starting with something smaller, but you would have to tap the center hole. It doesn't have to be square, so don't rule out using round stock to start with.


----------



## cdhknives (Sep 10, 2014)

Thanks for the comments!

I don't think I can grab enough of the nut with my 4 jaw to hold while turning.  I have a nice belt grinder that can thin the nut as required though...seems like no need for precision on the bottom other than leaving as much as possible for strength.  With the bolt installed it gets trimmed to fit at the same time.

I do have some new endmills and the milling attachment for my lathe but other than setting it up to see how it fits I've never used it.  Time to try something new I guess!


----------



## Round in circles (Sep 10, 2014)

cdhknives said:


> I got a Phase II AXA wedge toolholder from Enco, and it arrived yesterday.  First thing was to machine the T nut.
> 
> The nut included is way oversize for my 10F.  Do y'all recommend machining down the supplied nut or starting anew?  I can think of several ways to start over, but just trying to get the square nut to round is a hammering interrupted cut and holding the nut tight enough to take a decent cut was impossible.  After an hour I had maybe 1/4" turned off the corners and quit for the night.  There has got to be an easier way!
> 
> ...





I too had some new " T " nuts that were too thick to go in the slot and also after adjusting ( see below )  they stood proud of the cross slide face ensuring that the tool post would rock it's self silly if used in that state . 
I slipped a 6 inch long threaded bolt  in the " T" nut and used a plain nut to lock nut the two together on the face that was not being ground at the time  then used it as a long handle .

Then it was a simple case of stand by the grinder and gently take off the excess on all outer edges till I got  a good " Just sliding"  fit (  have the cooling water pot filled and handy ) .
Do remember to trim the sides & faces of the " T " , evenly so it stays central & vertically square in the slot so  that pressure will be evenly distributed in the "T slot ".

 I finished it in the bench vice with a dead smooth hand file clogged with chalk to get a fine finish on the sliding faces & gently champhered all the new cut sharp edges so they wouldn't catch when it was slipped in the " T " slot . .


----------



## Charles Spencer (Sep 10, 2014)

I think I might be missing something here.  Why do you want it round?

I just cut mine down to fit in the slot.  I used a bandsaw and a milling attachment and saved as much material as possible for rigidity.  If I didn't have the milling attachment I would have hacksawed, ground, and filed it.

Charles


----------



## jererp (Sep 10, 2014)

This is how I did mine. I mimicked something I saw online.




This is how I machined the T-nut to width. I just turned to the scribed lines I put on it, keeping the threaded hole central.

To machine the thickness, I ended up chucking up the threaded rod, and threading the T-nut on it as shown below.




And here is the finished product.


----------



## Bill C. (Sep 10, 2014)

cdhknives said:


> I got a Phase II AXA wedge toolholder from Enco, and it arrived yesterday.  First thing was to machine the T nut.
> 
> The nut included is way oversize for my 10F.  Do y'all recommend machining down the supplied nut or starting anew?  I can think of several ways to start over, but just trying to get the square nut to round is a hammering interrupted cut and holding the nut tight enough to take a decent cut was impossible.  After an hour I had maybe 1/4" turned off the corners and quit for the night.  There has got to be an easier way!
> 
> ...



Nice tool holder.  It is a shame it is some sort of universal mount when they say the nut may need machining.  Do you have a power bandsaw to cut the wings down to size?  Good luck


----------



## cdhknives (Sep 10, 2014)

Day 2:  Got the mill attachment set up and locked in.  I need to take about .40" off both sides and a yet to be measured out of the thickness to get it to fit the slot.


I wish I had a 4 flute mill.  This one is working, but it is noisy as I apparently can't keep a flute in contact at all times.  I don't care about surface finish, I need to cut it all off.  That's what I get when buying bits and pieces as I can find them.


Questions:  I'm taking a .015" depth by .40" wide pass, feeding at 40 seconds per inch, spinning the bit at 685 RPM.  It 'feels' good, the cut is a low rumble without undue grabbing or vibration.  Good, too slow, too fast, recommendations?


----------



## JimDawson (Sep 10, 2014)

I would say you are doing it just right.


----------



## SG51Buss (Sep 11, 2014)

That is almost exactly the way I machined mine last year, got a kind of deja-vu looking at your pic.
I used an MT2 drawbar collet instead.  Same cutting configuration, except used 0.003" depth of cut (smaller lathe).


----------



## cdhknives (Sep 13, 2014)

Day 3:

The local machine shops are in no danger from me...but it got done, it's tight, and in the end it was pretty square.  I 'finished' it oversize and not parallel the first time, so I had to back up, re-square the mill attachment to the bit, and take some light cuts to square it up and shave off enough to fit the slot.  I don't know if something slipped, or if I was off and flipped the nut wrong, but it came out slightly wedge shaped at first.  I had enough metal left to make it work...pure luck I assure you!


----------



## JimDawson (Sep 13, 2014)

Great Job!  And the good news is that in the end it works just like you wanted.


----------



## wa5cab (Sep 14, 2014)

If you hadn't told us that you had to go back and square it up, no one would have ever known.  :thinking:

One tip - if you had run an end mill with half the diameter, you could have run twice the RPM and not had as much low frequency vibration.

What is the serial number of your QC54?


----------



## Charles Spencer (Sep 14, 2014)

That's about how I did mine.

Charles


----------



## cdhknives (Sep 14, 2014)

wa5cab said:


> If you hadn't told us that you had to go back and square it up, no one would have ever known.  :thinking:
> 
> One tip - if you had run an end mill with half the diameter, you could have run twice the RPM and not had as much low frequency vibration.
> 
> What is the serial number of your QC54?



Serial # conversation already in progress in your sticky...:thumbzup:

My dual speed pulley is off balance, so running it in the high speed position results in too much vibration.  Direct drive, lower speed at motor + highest speed at headstock is about the fastest (675 RPM IIRC) I can run comfortably, and that turns out to be perfect for a 1/2" 2 flute mill.  What I really need is a 4 flute mill, but most of my tooling is odds and ends I find here and there, so I got what I got.  A new pulley is on the wish list...


----------



## cdhknives (Sep 14, 2014)

Old stringy scrap aluminum, left side cut last year with wobbly old toolpost and 1/4" HSS tools, right side cut with new toolpost and new carbide tooling.





Oh yeah...!!!


----------



## wa5cab (Sep 14, 2014)

Can you slow the feed rate down any more?  Looks like it is set at something like .010".  Unfortunately, the installation instructions for the 10" QCGB's do not give the feed rate specs and I'm not sure they are the same as on the 12".

On the S/N, you're right of course.  My memory for names has never been very good.  Nomenclature, no problem.  Names, nyet.

Robert D.


----------



## cdhknives (Sep 15, 2014)

The feed is set to the slowest available, .0042 IIRC.  I probably need to buy some larger radius cutters for better surface finish.  I was thinking threading when I got these with the smallest radius tip available.  That is probably what you are seeing.


----------



## chips&more (Sep 15, 2014)

That finish looks like motor harmonics to me or noise/play from somewhere. I have seen it before. If you have a belt(s) in the drive train, I would check the tension. You don’t need it snappy tight. More like 1/2” flex…Good Luck.


----------

