problem with new chuck

[DonHo]

I purchased the nova precision midi chuck from Woodcraft when it was on sale. I was going to use it with the "woodworm" screw that comes with it but when I screw on the wood it loosens the jaws from around the screw. The chuck came with pretty sparce instructions but as far as I can tell, I followed the directions. I think I could probably mount the wood on the screw then put the screw in the chuck( haven't acutally tried that yet ) but I'm afraid that the pressure of working on the wood would cause the screw to loosen. BTW, I also have a PSI chuck that comes with the screw and I don't have a problem with it. Any ideas about what I might be doing wrong??

Thanks in advance,
DonHo

[Tom Miller]

I just purchased that chuck, too, but haven't had a chance to try the woodworm screw yet. But, since I'm in the shop right now, I tried it out, and it seems to work correctly for me.

I left the jaws on, and inserted the woodworm screw such that it is captured in the jaws, with the flats of the screw meeting the flats of the inside jaws. Using the tommy bars, I snugged it up just slightly. Then, when I mount a piece of wood it holds solidly.

Is this roughly the technique you're using?

Regards,
Tom

[DonHo]

Sounds pretty much like what I did. I put the chuck on the lathe, then put the screw in the opening and snugged up the jaws with the bars. I then tried to screw on a 4"x3" piece of cedar by holding the hand wheel and screwing the wood on the screw. I tried 3 times and all three times the jaws loosened up and the screw came out of the chuck. I changed to the PSI chuck and followed the same procedure and had no problem. I'm wondering if I installed the grub screw wrong. I couldn't find much on the instruction sheet about it.

DonHo

[onedash]

I just got one too. Did you put that tiny red dot (washer material?) in first? That seems to make it pretty snug. Quite a bit harder to open and close...
When should you use that wood screw????when the piece is to small for the chuck??? Why would you use the chuck at all in that case?
I have had a lathe all of 2 days and my first attempt at a bowl ended up in the scrap bucket(what was left of it after it blew out the bottom)
Doing ok with pens though....

[DonHo]

Yes, I did put the fiber washer in first but I may not have tightened the screw enough. I didn't find any instructions as to how thight it should be but since I've had problems with the chuck coming loose that might be the problem. I'll look into tightening it some.

In answer to what the screw is used for, it's actually used to mount larger pieces of wood like a bowl blank so you can turn the outside of the bowl then either make a spigot or a rebate on the bottom so you can turn the blank around and mount it on the chuck for turning the inside of the bowl.

DonHo

[Tom Miller]

FYI -- I hadn't put in the fiber thingy on mine yet when I tried out the wood screw yesterday. Just don't want you to be barking up the wrong tree.

When you say it loosens up, do you mean it just gets a little loose, or do the jaws continue to open as though you were spinning the two chuck pieces opposite each other?

Regards,
Tom

[DonHo]

"When you say it loosens up, do you mean it just gets a little loose, or do the jaws continue to open as though you were spinning the two chuck pieces opposite each other?"

The jaws continue to open as the piece is tightened. Not at a fast rate but they open enough that the screw comes out before the piece is fully mounted. I haven't checked yet but it may very well be that I didn't tighten the grub screw enough because I can turn the chuck to adjust the jaws by hand before using the tommy bars.
DonHo

[Tom Miller]

Don, have you figured anything out yet? Can you easily open and close the chuck jaws by hand? I can just barely operate mine by hand, and that's without having installed the set screw with the little friction "dot".

I actually used the wood screw the other night for its intended purpose (prior to that, I had just mounted a piece on it, without actually turning). Several times I noticed the piece got a little wobbly, and found the piece was getting loose on the screw. But the screw was still firmly captured in the chuck.

I think this is the first time I've used this type of wood screw in a chuck like this, and I was a little surprised at how it loosened up on the screw. I thought the forces involved would make it tighter. But, somehow, when I'd get a little catch, it'd loosen -- when the piece was roughed smooth, it stayed tight.

Regards,
Tom

[maxparot]

While attempting to install my Nova chuck on my HF lathe I found it threaded so far on that it interfered with the chucks operation. It wouldn't fully close it's jaws. I punched out a couple of fender washers so they would slip over the threads to use as spacers. When I installed the first it allowed the chuck to close but it was still rubing the shaft and took too much effort to close fully. A second washer spaced it out enough for proper operation.

[final_t]

I've never been able to figure out how to properly use the WW screw on the chuck, and just gave up on it. Any clues (with pics beg beg beg) would be great...

[Tom Miller]

I've never been able to figure out how to properly use the WW screw on the chuck, and just gave up on it. Any clues (with pics beg beg beg) would be great...

I'm up for it, not that I think I'm using it correctly, but because I'd like some confirmation that my technique isn't misguided.

Regards,
Tom

[Tom Miller]

OK, I snapped some pics:

This one shows the screw partially captured in the jaws. Note that a portion of the jaw bottom fits into a recess in the screw.




Then, snug it up a bit, but still allowing a little back-and-forth movement, and pull it forward.




Drill appropriately sized hole in your blank (this one has already been roughed).




Mount the blank onto the screw, and be sure the screw is pulled all the way forward when the blank is snugged up to the jaw faces.




Comments? Questions? Suggestions?

Regards,
Tom

[final_t]

Cool, thanks Tom! I'm going to give that method a try. I think my problem is that I was doing it without the jaws in place, just the bare chuck.

Also learned today that I've been using the burring tool for the scrapers backwards

[DonHo]

Well now, those pics might have solved my problem. Somehow I got the idea that the front "flange" on the screw was susposed to be behind the jaws. I'll try your way tomorrow and see if that works for me. Somehow I bet it will

DonHo

[Tom Miller]

Hey guys, glad my pics helped! Let me know how it goes once you try it again.

Like I mentioned earlier, I still had a little "loosening" problem when I was roughing the bowl; either it occurred as a result of the cut getting rough, or the cut got rough as a result of the piece becoming a little loose. But, it wasn't the screw getting loose in the chuck. It was the blank getting loose on the screw. Or, maybe I hadn't payed attention to pulling the screw all the way forward in the chuck....

Regards,
Tom