check spun off spindle

Were you sanding in reverse?

George Taylor

and if you did, I suspect the lock screw was not there or tightened. Otherwise there should be no way the chuck should spin off the spindle.

George

Re: check spun off spindle

john lucas

In rare cases I have had a chuck come loose with lathes that have electronic braking. If you don't put the chuck on firmly that can happen. It happened with me when turning a 19" bowl. fortunately it hit the tool rest and stopped instead of flying across the room.

As far as the gears being tight simply remove the insert, then remove the 2 screws that hold the backing plate on and then clean and inspect the inside to see of you have a problem. My experience with my Vicmarc's is they have been running perfectly for many years. Possibly you got some dirt or grit in side.

Re: check spun off spindle

Barry Rockwell

That big chuck is so massive and heavy that you really need to cinch down the set screw when using it. If your lathe has any kind of breaking at all, that chuck can spin off unless the setscrew is used. I have never had to use a setscrew on any of my other Vicmarc chucks, but with that one I never turn without it.

Re: check spun off spindle

ben d.

If your lathe was at high speed and you just put the chuck on by spinning it on , turned the lathe on and then went to a slow speed the chuck will screw itself off.

Don't ask me how I know.

ben d.

Re: check spun off spindle

robo hippy

If the gears on your chuck are not moving smoothly, most likely it is from gunk, dust and other stuff on the inside. Here is the best video I have seen on taking your chuck apart, cleaning it, and putting it back together:

https://www.youtube.com/watch?v=-S-NZSqaPuo

Chucks didn't have set screws when I bought mine, so like electronic rpm indicators, I never learned to use them. I snugged them down fairly well, and the only time I had things come loose it was from hand sanding in reverse, and using too much pressure, again, a learned habit. Perhaps getting the chuck on snug to start is the main thing here. I used the hard plastic washers for a few years because I figured they worked some thing like a locking washer, but stopped using them a while back. No problems. If you have a long day of turning, I figure that does a lot to lock the chuck in place as it is a counter force. If the chuck comes loose when you turn off the lathe, I figure that could be in part because the chuck wasn't on snug to start with, and/or the electronic brake is set to stop too quickly. I really don't know what the timing on most lathes is.

robo hippy

robo hippy

make sure it's tight to start with

John K Jordan

>Perhaps getting the chuck on snug

>to start is the main thing here.

What has always worked for me (Jet 1642): thread the chuck onto the spindle except for about 1/2 turn, then give it a quick twist. This is not enough force to hurt anything but locks the chuck so it requires a good pull of the wrench to get the chuck off. (BTW, I won't use a chuck key as a wrench)

I don't use the set screws, washers. Nothing comes loose.

The VFD on the 1642 is set to 5 second deceleration. This can be programmed to longer times if that is a problem.

JKJ

Re: make sure it's tight to start with

john lucas

I found the quick twist to be too hard sometimes making it hard to get the chucks off. What I learned years ago from the other John Jordan is to put the chuck on until it's snug. Then give it a push with the chuck key to snug it up more. This has always worked for me and it's seldom difficult to get off. I would say never but every once in a while it still locks on. Probably when I"m turning larger difficult woods.

Interrupted cuts

Geoff Whaling

Interrupted cuts when roughing blanks will tighten the chuck / insert onto the head stock spindle thread so tight that you have to resort to more force than usual.

The difficulty opening the jaws is most likely from accumulated gunk in the scroll & backing slides, however it could be from damage / miss use. Just requites a bit of TLC.

A chuck that spins off in use or deceleration of the lathe is usually associated with not fitting the chuck correctly. A chuck than can spin of the spindle is a hazard & is not safe, you really need to do something about correcting your procedures to fit the chuck correctly. Sanding / turning in reverse is also a very significant hazard IF the chuck is not set up correctly.

Is it a VL120/140 or a newer VL150 chuck? What lathe model? What style insert ? Vicmarc or another supplier?

Most recent Vicmarc supplied chuck inserts have provision for the grub screw locking & later versions have a locking collar which fits over the head stock spindle & chuck insert. The collar is suitable / compatible with later versions of Vicmarc lathes only.

The Ian "Robbo" Robertson YouTube clip is a good one on Vicmarc chuck maintenance. I did an article on Nova & Vicmarc scroll chuck maintenance in the AAW magazine (29-3). The maintenance is not difficult as there are not a lot of moving parts in a geared chuck, but please for your safety remember to refit the scroll stop pin on typically jaw slide #4.

Marco Verricha from Vicmarc also has a video on their FB page about Vicmarc scroll chuck maintenance, https://www.facebook.com/search/top/?q=vicmarc%20machinery%20pty%20ltd

...and not too tight, yes!

John K Jordan

>I found the quick twist to be too hard sometimes

>making it hard to get the chucks off.

I can see how that could happen - sorry, I should have cautioned about that. It doesn't take much.

I think I must have developed a calibrated wrist flick over the years since the chucks are always what I think of as just right - requiring a reasonable tug on the wrench to remove but never stuck hard.

When I first started this method I tested with a light spin then gradually increased until removing the chuck felt right.

JKJ

(I found out earlier today: attempting to reply to a post using the browser on my Motorola phone is apparently futile)

leavea a 1/2" gap and turn the lathe on full speed

john lucas

I can guarantee the chuck won't come off then.