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QCTP Base Question

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brino

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#32
Hi, I just wanted to post back that I have just downloaded, installed and registered Fusion 360 as an "Enthusiast".

To register, just click on the countdown of days left in your trial period and it pops up this window:

upload_2017-3-9_19-0-17.png

Now the learning curve begins.........

-brino
 

Bob Korves

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#33
I was able to sign up as well for the 30 day trial. I know to go to enthusiast when the trial period is up. Thanks, Brino!
 

q20v

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#34
Glad to hear it worked out. It's a great piece of software considering it's free!
 

Cadillac STS

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#35
Autodesk has a great Student/Educator program. Can get a full license for any Autodesk product for 3 years for the asking if you are a student or educator. I use Inventor HSM free being an associate professor at Michigan State. I think High Schools should be all over that and get a license for each and every student. Maybe some kids could become an absolute expert at AutoCAD or REVIT or Inventor HSM or one of the several other professional software packages by the time they graduate instead of just spending thousands of hours with video games. Schools could hold contests and events around software learning goals. FREE use of the software your company has to spend thousands of dollars for so you can sit at the company on company time learning it. They would graduate High School and if expert walk into an $80k job just like that. Some kids would be brilliant and gifted with it.

Fusion is different and free to use. Fusion is web based. That solves a problem with highly complex graphics, it takes a powerful computer to run some of the software due to that. But with Fusion the idea is YOU have an interface (Doesn't need to be a powerful expensive professional style computer.) and THEIR powerful computers crunch through the work of it so you don't need to have a powerful computer and send your work back to you in real time. Solves the hardware issues and allows more people too use it especially at home. And easier to share drawings, etc..
 

Cadillac STS

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#36
q20v

Thanks for your positive response. Just to be clear I am not saying that there is a problem with either style of T nut.
However, when I faced the same situation of mounting a new QCTP without the capability of milling the blank, I opted to use the existing round T nut and save the new square blank for posterity. I did not see the point of having two round T nuts.
It did require that a new bolt of the proper dimensions be threaded to fit the old round T nut and that was a fun exercise in itself.

It turned out to be relatively easy to do a bit of milling on the lathe. So I have both style nuts now.

Looking forward to seeing the results of your analysis.
View attachment 228063
Not hijacking the thread but a question about the round base in the picture. I bought a used BXA QCTP for a project and it came with a round base like that. What type of lathe is it from? I made a T nut and took off the round but wondered where the base came from.
 

Catcam

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#39
Just a thought but the square style would be more rigid than the round one.
The square milled profile would be more rigid, but it may not be necessarily warranted. depends on the relative stresses which should be minimal overall.

I also had that issue and to solve the problem of not having a mill at the time. I machines a new bolt for the QCTP to use the existing compound nut. all worked fine it is still there.
 

Cadillac STS

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#40
It is nice to make your own part. But it should be said that you can buy a pre-made T nut with any thread pattern you want on eBay. Search "Lathe T nut." There are a few people that sell them for common lathes and if you contact them with your specific measurements could likely make what you need. $15.
 

Tozguy

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#41
Barry, just curious about something.
Is the T nut blank that came with QCTP too wide to fit in the compound?
Will you have to cut some off of each side of the blank before (or after) turning the boss to the right depth and diameter?
If yes then how do you plan to do that?
Mike
 

q20v

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#42
Hey Mike,

Yes, I'll have to reduce the width. I was thinking of mounting it in the 4-jaw chuck and facing it (both sides equally). I've never used the 4-jaw so I'm hoping this approach is do-able. I'm all ears if it isn't.

Barry
 

Tozguy

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#43
Its worth a try.
Interrupted cuts like that can be noisy and hard on tools but if you go slow it should work.
If you have much to take off then maybe rough it out first with a hacksaw or angle grinder.
 

q20v

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#44
That is a big interrupted cut to deal with, good point... I don't believe I have much to remove but may save some time grinding a bit off, first. Come to think of it, the lathe did come with a milling attachment that I intended to use after I made my Collet Closer w/draw bar. When I got the lathe the milling attachment went under the bench and I haven't looked at it since. Think I would have much luck holding an endmill in the 3-jaw for this?
 

Tozguy

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#45
Re the interrupted cut, I have done a few like that and got away with it. Depends on how rigid the set-up is. If you start in the centre where the cut is continuous and move outwards until it starts to interrupt you will gradually see how it goes.

For milling on the lathe I would not use a 3 jaw scroll chuck to hold the milling tool.
A 4 jaw independant chuck would be a definite maybe but I have never tried it.
If you have an MT socket in your lathe spindle, a Weldon style holder would be the most expedient and least expensive way to go.
http://www.busybeetools.com/products/e-m-holder-mt-3-1-2.html
Then make your own drawbar.

Hopefully your milling attachment will work for this. Before I made my own milling attachment this is how I managed. It requires a lot of shimming and indicating as you can imagine. If you have a 4 way tool post it could be used to hold the blank.
 

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Chips4Lips

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#46
Your simulations are an extremely interesting way to prove or dis-prove the theory but I would also wonder about adding a small radii where the round column meets the flat portion - also would require adding a slight larger radii along the underside o fthe two retainlin ledges. This gets into some serious "home shop work" but we're trying to find out how to gain as much as possible regardless of the method so maybe that's something of another option. When I say "small radii" - I"m estimating something like a .125 radius with a relief radii of about .140" - would have to use a form cutter to achieve this most likely but it's possible. Will look forward to the results if this sounds of interest. Thanks.
 

Charles Spencer

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#47
Before I made my own milling attachment this is how I managed. It requires a lot of shimming and indicating as you can imagine. If you have a 4 way tool post it could be used to hold the blank.
Clever - shows a lot of ingenuity and can do spirit.
 

q20v

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#48
Hey guys,

This past week I finally managed to machine my QCTP base. This included:
1. reducing the width, approximately 10mm each side.
2. reducing the thickness by approximately 8mm (not including the boss in the center).
3. turning the boss diameter to size.

The interrupted cut for the width reduction wasn't all that bad. Chips really flew and I took light passes. After 3 or 4 passes I decided to take a meaty slice off with an angle grinder and finish on the lathe.

Everything else went very smoothly. This was my first time on the 4-jaw chuck so I was a bit slow setting it up, but got it in the end. I hit all dimensions within the specified tolerances (well, the tolerances I specified going into this project) and it fit perfectly, and nicer than the base for my turret tool post (less play). A huge relief because I didn't want to re-mount this in the chuck after I was done.

Here are a few pictures from last night:



To center the boss, I first machined it way oversized and took measurements from side to side, and adjusted the 4-jaw until they were equal.








 

joshua43214

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#50
q20v

Thanks for your positive response. Just to be clear I am not saying that there is a problem with either style of T nut.
However, when I faced the same situation of mounting a new QCTP without the capability of milling the blank, I opted to use the existing round T nut and save the new square blank for posterity. I did not see the point of having two round T nuts.
It did require that a new bolt of the proper dimensions be threaded to fit the old round T nut and that was a fun exercise in itself.

It turned out to be relatively easy to do a bit of milling on the lathe. So I have both style nuts now.

Looking forward to seeing the results of your analysis.
View attachment 228063
My QCTP (from Quality Machine Tools) came with a round "nut" like shown here. Do yourself a favor and get rid of it.
If any of you have a similar set up and are having unexplained finish issues, this is a likely culprit.

I was having random problems with finish quality, replaced the nut and they went away. The nut is so thin it acts like a spring, and will set up a vibration under certain cutting conditions like being in the middle of a long part that wants to flex away from the tool.
I actually saw the whole rig flex up while cutting a very deep thread on a piece of O1 tool steel for a hob right before it made a loud "bang" and snapped the tip right off my tool.
 
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