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How do YOU make a "T" nut for your QCTP?

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Nelson

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#1
You buy a new QCTP and it comes with an oversize "T" nut that you have to mill to size.

How do you do it? (Photos if possible). How do you measure the correct dimensions of the T-slots, set up the job on the milling machine or other machine that you use, and remove the excess material.

This is an important task for newbies.

Thanks,


Nelson
 

aametalmaster

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#2
Re: How do YOU make a

I know how i made your tee nuts with my shaper...Bob

teenut3[1].jpg teenut2[1].jpg
 
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pdentrem

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#3
I used hack saw to rough out the nut and then set it up in my milling attachment to finish the nut. The first one I used the saw method but finished by file as I did not have the milling attachment at that time.
For my new set of Phase II, I am making a new top slide for the compound and will just drill and tap a hole for the tool post bolt. I hope to finish it this week.
 

PurpLev

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#4
Re: How do YOU make a "T" nut for your QCTP?

I measured t slot dimensions with a caliper, cut out a rough block of steel, and using a milling machine squared and dimensioned the part to size, and milled out the T rabbets:

2012-03-21_22-32-39_419.jpg

Sorry I don't have any in-process photos, but these were basic milling steps - squaring and dimensioning a part, and milling a step at a certain depth from a (dialed in) edge.

If you are looking for some basic milling tutorials/lessons/whatnot I highly highly recommend Darrell Holland videos on lathe work and milling:

http://smartflix.com/store/author/75/Darrell-Holland

very very well made.

2012-03-21_22-32-39_419.jpg
 

AR1911

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#5
Re: How do YOU make a "T" nut for your QCTP?

Well, I didn't know enough to do it properly. All I had was a 9" lathe

First I measured the compound to determine the dimensions, and marked the areas to be removed on the supplied t-nut blank.
I chucked that blank endwise into the 4-jaw and faced it down to the correct width.
I installed the QCTP stud in the blank, then chucked it in the 3-jaw. I faced of off down to the correct thickness. Length was OK. Now I had a blank that was correct thickness, length, and width, just needed the steps milled.

I made a round t-nut in the lathe to fit my topslide. Sort of a stepped washer/nut, tapped in the center for the TP stud.
This let me temporarily mount my new QC post. I probably could have used this indefinitely, but it does not spread the load across the casting as it should.
Then mounted the blank that came with the QCTP into one of the toolholders, using it as a milling vise.
I chucked a 1/2 endmill into the 3-jaw chuck (Bad idea, collet is best).
I adjusted the height to get the cutter where it needed to be, then milled off the shoulders to the correct dimensions.

Replaced the round t-nut with the newer version.
This works OK because the tolerances are very loose.
 

xalky

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#6
Re: How do YOU make a "T" nut for your QCTP?

I used hack saw to rough out the nut and then set it up in my milling attachment to finish the nut. The first one I used the saw method but finished by file as I did not have the milling attachment at that time.
For my new set of Phase II, I am making a new top slide for the compound and will just drill and tap a hole for the tool post bolt. I hope to finish it this week.
I didn't have my mill when I cut mine to size. I did it in a similar fashion to you. I rough cut it close on my band saw and hand filed it. It doesn't have to a dead-on fit but I got it pretty darn close by hand with a file. It's a real simple job on a Bridgeport. Sorry, no photos either.
 

Benji

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#7
Re: How do YOU make a "T" nut for your QCTP?

You really do not need anything more than a lathe.
First rough cut to size. I used a horizontal band saw but a hack saw and a lot of sweat would work.

Rough-cutting-to-size.jpg

Then chuck the OVERSIZE part in your lathe with a 4-jaw and finish both sides. Make the width 0.010 undersize and center the edges on the tapped hole.

4-jaw-side-1jpg.jpg

Now break the corners. Remove any buildup.
Next I screwed the blank onto the shaft it came with and chucked it up in a 3 jaw chuck. I turned a stub the width of the compound slot less 0.010.

machining-boss-to-fit.jpg

Doing it this way insures the boss is concentric with the screw shaft and the top flat is at right angle to the Boss. Again allow 0.010 in the thickness.

Break the top corners to allow clearence from and radius in the corners of the compound tee slot.

This was for an Atlas 10" lathe and here is how it fits.

Post-after-trimming.jpg
 

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ScrapMetal

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#8
Re: How do YOU make a "T" nut for your QCTP?

I also used the method that Benji did, with the exception that I used a 4-jaw chuck without the bolt/shaft and mine was for a SB.

BXAbase03.JPG

Trimming to width


BXAbase06.JPG

Using a 1-2-3 block to space it in the chuck and a combination of two jaws and live center to hold it in position.

BXAbase08.JPG

Almost finished.


BXAbase09.JPG

Fitting it to the compound.

-Ron
 

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xalky

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#9
Re: How do YOU make a "T" nut for your QCTP?

Thats another way to do it. You guys making stuff on your lathes that I never thought possible. :thinking:
 

Hawkeye

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#10
Re: How do YOU make a "T" nut for your QCTP?

Okay. I guess I have to put in a little tool gloat here. I never expected to have a mill that could do this.
P1010067a.jpg

Those are 6" diameter cutters on a 1 1/4" shaft. The hubs on the cutters are flush with the edges of the teeth, so the thickness of the shims equals the space between the cutters.
P1010070a.jpg

With the right setup, one pass completes the profile. Feel the power!

P1010067a.jpg P1010070a.jpg
 

ScrapMetal

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#11
Re: How do YOU make a "T" nut for your QCTP?

Show off!! :rolleyes: :lmao::lmao::lmao:

Just wait Mike. I'll be able to do that too as soon as I get mine all set/tooled up. :p :biggrin:


That is very cool. Really makes me want to put a little more effort in to get my horizontal motor in to play on the W-I.

-Ron
 

davidh

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#12
Re: How do YOU make a "T" nut for your QCTP?

hawkeye, you suck. . . . . .:phew: (thats a compliment) that makes the job wayyyy to easy. . . . .
 

george wilson

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#13
Re: How do YOU make a "T" nut for your QCTP?

The important thing is to make sure that the sides of the inverted "T" are parallel,if you file it out. If not,your lathe compound could be broken by unequal forces,too few contact points,etc,pulling up on the compound when it is under tension during a cut.

If you can't make the T nut any other way,just turning the round riser in the lathe is perfectly O.K.,because the only purpose of the tall part of the T nut is to make the threaded hole deep enough to make strong threads.

At least,if you face this part in your lathe,leaving the tall neck, you can be sure it is parallel,and will touch the T slot in the compound everywhere properly.If you must make it by hand,use blue paste to check that it fits everywhere under the T slot in the compound.
 

ScrapMetal

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#14
Re: How do YOU make a "T" nut for your QCTP?

I agree with you Frank. The method you suggest is pretty much the one I prefer using. Unfortunately if one doesn't have a mill (or shaper) available to them they need to have an alternate way to get it done. That's where the "lathe method" comes in to play. It's also my "gut instinct" that the "T" with the rounded portion, as produced by the lathe, would not be as strong or as rigid as a conventionally shaped "T" but it would take some good structural analysis to determine if those differences are great enough to have any affect on the system. (I would like to see such analysis if anyone was looking for something to do... :biggrin:)

In this case it didn't matter how much setup time it took as it was still faster than trying to accomplish the same thing with a hacksaw and file.

BTW, once I get my shaper back to life or now that I do have a mill, I will probably make a couple more "T"s.

Thanks,

-Ron
 

AR1911

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#15
Re: How do YOU make a "T" nut for your QCTP?

that steel tee-nut is going to be stronger than the cast iron compound is, round boss or rectangular.
 

Chucketn

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#16
Re: How do YOU make a "T" nut for your QCTP?

Then I drill and tap the threads for the stud. Screw in the stud and use red locktite. I revese the "T" with the stud installed and drill and tap a dutchman
Frank
I can't find anything to explain what a dutchman is as in Frank's post. Can anyone explain, or provide a picture or reference for me?

Chuck
 

Tony Wells

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#17
Re: How do YOU make a "T" nut for your QCTP?

Dutchman's pin


Although I can't imagine going to all that trouble for a tool post stud. Or Loctite either for that matter. Just good threads are sufficient. One could also use drilled and tapped holes instead of pressed in pins. Not worth the effort.
 
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Chucketn

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#18
Re: How do YOU make a "T" nut for your QCTP?

Thanks for the explanations Frank and Tony. I actually knew what they were, and have used them, just had not heard them called a Dutchman.

Chuck
 

rogerrabbit

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#19
Re: How do YOU make a "T" nut for your QCTP?

Wow, this thread is perfect, just got a shars bxa sized qctp.

I want to make a t nut for my clausing lathe.. the dimensions of compound t slot are (roughly) t-width 1 3/8, t thickness 1/4, throat width 1, throat height 5/16, compound width 2-3/4.

my choices are 3/16 square plate steel.. unknown type or 2024-t351 aluminum (alcoa brand is stamped on it).
I would like to use the aluminum as I have enough thickness, but will that be strong enough to hold the qctp?

the center post is 5/8 with 5/8-18 threading on it.

I don't feel comfortable machining the original (yet).

thanks!

Roger
 

george wilson

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#20
Re: How do YOU make a "T" nut for your QCTP?

IF you have a LARGE,powerful lathe,the T nut needs to be made as rigid as possible. But,for the smaller home shop grade machines most here likely have,I think the round top T nut would be good enough. I do make parallel topped T nuts myself,but I have a 16" lathe,and 3 milling machines,so I can do whatever I want. Every time I buy a new thing to mount on the T slot,like a toolpost grinder,I have to make a new T nut,and I have 2 different lathes,so it has happened several times that I make T nuts.
 

ScrapMetal

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#21
Re: How do YOU make a "T" nut for your QCTP?

Ditto to what Frank said. :thumbzup: I'd like to add a bit as well. If you are making your own "T" make sure that the stud cannot screw in so far as to go completely through the "T". If this were to happen when you were tightening it, you could break the "ears" off the compound or do other nasty damage. On my Aloris "T" stock they left the last couple of threads un-cut or missing so it can't go through. Even if you use loctite it can come loose after a time (if not used properly) so be sure to do it right. Frank's suggestion of pinning would also be a good way to prevent this from happening.

-Ron
 

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#22
Re: How do YOU make a "T" nut for your QCTP?

thank you.. ok, aluminum is out.. hadn't thought of the threads, I was worried that 1/4 for the ears of the t would not be strong enough.

Ron,
good tip on not threading through all the way..

--Roger
 

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#23
Re: How do YOU make a "T" nut for your QCTP?

To avoid screwing the tool post screw all the way through the T nut,and erupting the top right out of the compound,don't thread all the way through it. If you have already done that,take a cold chisel,and damage the threads at the bottom of the T nut's hole to stop the screw from protruding through. You can see similar treatment on the set of T nuts you buy for the milling machine. Their bottom threads are damaged to avoid pulling a hunk out of the T slots on the milling machine's table.
 

Tony Wells

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#24
Re: How do YOU make a "T" nut for your QCTP?

Or if the stud's length will allow it, face it off so that the length of thread is slightly shorter than the thickness of your plate.
 

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#25
Re: How do YOU make a "T" nut for your QCTP?

then install the "Dutchman"
I understand the concept and how a "Dutchman" works but how exactly do you install one on a QCTP? Do you simply drill and tap a hole from the bottom of the T-nut at the point where the stud meets the T-nut? Then install a threaded pin? I've attached a drawing with how I think it would be done. Is that right? :headscratch:
 

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Tony Wells

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#26
Re: How do YOU make a "T" nut for your QCTP?

You got it, Kent. Some people drill and ream a hole for a spring in, just because it's simpler, and no chance of tap breakage, but a set screw works fine too. And you only need one to prevent any rotation. And it doesn't need to be terribly long. The prevailing torque in the situation created by loosening the nut on top is actually pretty low, so it doesn't need much to hold it.
Actually, the most difficult part (and it's nothing, really) is to prevent the stud from turning while you drill/ream/tap, whatever you decide. A drop of Loctite would solve that simply enough.
 

architard

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#27
Re: How do YOU make a "T" nut for your QCTP?

Frank,
Thanks for the added information. Exactly the type of explanation an amateur like me needs. Yes, it would make total sense to place the "dutchman" 90 degrees to where I showed it. That was my 1 minute sketch I drew at work while I should have been doing something else. :nono:

I was about to ask what NF was but a quick google search got me to National Fine Thread.

Thanks again!
 

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#28
Re: How do YOU make a "T" nut for your QCTP?

Jumping in late, just made a set out of 6061 alluminum for my 10" rotory table, and drill press. Am I heading for a giant disastor? The threads are 3/8-16 x 1". This was all that was availabe at the time. Any input would be helpful, don't want to end up an internet failled story.:phew:
 

epanzella

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#29
What would this thread be without at least one hack? I needed an extra T nut for a fixture so I used two pieces of plate. I cut the top one to the narrow width and the bottom one to the wide width of the slot. I welded them together and tapped for the fixture. It was supposed to be temporary but I still use it 6 years later.

DSC_0900.JPG
 
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