problems with union graduate lathe and patriot chuck

[woodchuckcharlie]

HI all,

I am having trouble with the patriot chuck winding on properly to the lathe on both sides- The first chuck I had seated on properly against the headstock but wasn't running true- I sent it back and was given a replacement- The second one won't wind on all the way- stops short about 15 mm from the register- they've sent me a third one to try- same thing- now I am wondering if the spindle on the Union Graduate may not be a typical tpi- or maybe there is something else I am missing? I'm new to wood turning and old machinery- but have invested a lot in this Lathe so hoping to get some help here.

thank you,
Charlie

 

[Duncan A]

You may find a solution here: Sticking Chuck

 

[Democritus]

Is the chuck sticking as you wind it on, that is, it gets to one point on the spindle and won’t go any further, but can be unscrewed?
If that is the case, it suggests that the the spindle thread at the sticking point is damaged. You may need a replacement spindle.
D.

 

[Paul Hannaby]

Do you have any chuck or faceplate already which has the 1 1/2" x 6tpi thread? If so, try those on the spindle to eliminate a damaged thread. If they are good, the problem lies with the chuck but check for any obvious burrs or deformation on the thread or register.

 

[Orraloon]

As Paul said above check the headstock thread for damage. More chance its the old thread than a new chuck or thats where I would first look. A small ding in a thread can be carefully filed back into line.
Regards
John

 

[Fergie 307]

As Paul said above check the headstock thread for damage. More chance its the old thread than a new chuck or thats where I would first look. A small ding in a thread can be carefully filed back into line.
Regards
John

If he's had one chuck that screws all the way on, and another, allegedly identical chuck, that doesn't then that tells me very clearly that the two chucks are not the same, which has to raise some doubts about their quality control. In fairness they have a good reputation so you wouldn't expect this. When you say the first one didn't run true, in what respect? Was it wobbling, or not concentric. As Paul says if you have something to screw on already, and it does so properly, then I doubt the problem is with the spindle. If you have got a faceplate, does that run true. If it does then that suggests the register and spindle are both ok. If not then it's time to get out a dial indicator to find out what is going on.

 

[woodchuckcharlie]

Is the chuck sticking as you wind it on, that is, it gets to one point on the spindle and won’t go any further, but can be unscrewed?
If that is the case, it suggests that the the spindle thread at the sticking point is damaged. You may need a replacement spindle.
D.

It is looking like this maybe the problem. Thanks I will as John has suggested carefully file the burr and also keep looking for a replacement. Thanks C.

 

[Fergie 307]

I don't know what options are available for your nose size, but have you checked that the second chuck is actually the correct size? If there are, for example 6 and 8 tpi options then if they have inadvertently sent you the wrong one it might try and screw on a little way before binding up.

 

[Fergie 307]

It is looking like this maybe the problem. Thanks I will as John has suggested carefully file the burr and also keep looking for a replacement. Thanks C.

If that is the case then why did the first chuck screw all the way on? Not sure I understand how you arrive at that conclusion.

 

[woodchuckcharlie]

If that is the case then why did the first chuck screw all the way on? Not sure I understand how you arrive at that conclusion.

I arrived at this conclusion because there was a nick in the first thread on both sides, so I carefully filled it away and kept trying the chuck I had it wouldn't go on, so I tried the new one they sent me and it went on fine after the adjustment to the threads. It seems like the second chuck has a problem with the threads and it won't go on.

 

[parvum]

I had the same issue with an exert for a patriot chuck onto Wadkin bzl spindle. The cause was the threaded recess in exert was not deep enough. A simple machining error. Sorby confessed to this being the problem but had no replacement at the time.Life is short and I have a metal lathe so the solution was straight forward. I would suggest you measure all relevant dimensions to eliminate a possible machining error.
Also the first chuck I was supplied had excessive runout, even for woodworking! All that glisters is not gold! Even well respected manufactures are victims of poor quality control sometimes.
I hope you find a solution soon and enjoy an excellent chuck.
Regards Paul

 

[clogs]

I'd be lost without a few of these.....
Old English, Unified and Metric....
thread files......

 

[woodchuckcharlie]

I'd be lost without a few of these.....
Old English, Unified and Metric....
thread files......
View attachment 155273

I have never heard of one of these.

 

[Inspector]

I have a couple thread files like that (they can be handy) but they are no where near coarse enough to do a lathe shaft. Using a triangular/three corner file needs care to use especially for your old 55º thread forms. Sometimes the little Swiss needle file sets work nicely.

Pete

 

[Fergie 307]

I'd be lost without a few of these.....
Old English, Unified and Metric....
thread files......
View attachment 155273

Oh yes, I have quite a few and they certainly come in handy.

 

[graduate_owner]

I have a graduate (1 1.2 x 6 tpi) and a Viceroy (1 1/2 x 8 tpi) and there is no way the chuck would go even one turn if it was threaded 1 1/2 x 8. I suspect the most likely issue is the recess in the chuck being not deep enough, although do check the spindle for any burrs or other thread damage.

K

 

[Fergie 307]

I have a graduate (1 1.2 x 6 tpi) and a Viceroy (1 1/2 x 8 tpi) and there is no way the chuck would go even one turn if it was threaded 1 1/2 x 8. I suspect the most likely issue is the recess in the chuck being not deep enough, although do check the spindle for any burrs or other thread damage.

K

Just thought it was worth checking. I was prompted to suggest that by the OP saying it was stopping 15mm short of the register, which would suggest it was barely going on atall. Looking at the pictures again it appears to be a lot less that that. Anyway I'm with you. If one chuck will screw all the way on, and another won't it suggests to me that there is a problem with the machining of the second chuck, either the thread not being cut deeply enough into the bore, or as you say the bore itself being too shallow. Disappointing when you have bought what should be a quality product from a reputable company. Whoever does quality control at the manufacturer needs a kick in the pants.

 

[Fergie 307]

Sorry If I appear to be harping on. If you found damage on the first thread, that might stop it going on atall, but certainly doesn't explain why it would go most of the way down and then bind. My concern is that the thread in the chuck is not correct. From a machinist point of view you can't really thread a blind hole all the way to the bottom. For that reason the hole needs to be deeper than the length of the spindle end, so the thread can also be machined deep enough to ensure it extends slightly beyond the end of the thread on the spindle. Otherwise you risk having a situation where the chuck might appear to be on correctly, but has actually bottomed in the thread, rather than being pulled tightly onto the register. This will cause the chuck to run out, and will also potentially damage the spindle. As Parvum says, I would carefully check the measurements, and in particular the depth of the hole, and of the thread itself.

 

[flh801978]

Here’s some pictures of a graduate spindle and the 2 types of patriot chucks to fit the spindle,one directly threaded rh and lh and the excert only rh
As you can see the thread and register is only 25mm long and both females are 35mm deep..
And theres only about 2.5 to 3 turns of thread on the spindle…