Chuck Issue

[Madman1978]

I was setting up last night so I could drill a few blanks. However, it was off-center by quite a bit. I looked a the check and the jaws seem to be not set right? One side was out further than the other. I need some help here. please? lol

 

[chartle]

Did you or do you ever take the jaws out? Looks like they were put in out of sync or swapped.

 

[Madman1978]

Did you or do you ever take the jaws out? Looks like they were put in out of sync or swapped.

I took them out to try to realign them. They seemed out of sync before that.

 

[Dick Mahany]

Looks to me as if the bottom jaw in the pic missed one thread start. I'd remove them and reinstall and carefully watch the scroll thread appear for the second jaw after the first jaw has started.

 

[Herman]

It seems simple. You probably opened the jaws beyond the thread limit. When closing, the jaw "jumped" the thread. Remove and replace the jaws again.

 

[Madman1978]

It seems simple. You probably opened the jaws beyond the thread limit. When closing, the jaw "jumped" the thread. Remove and replace the jaws again.

I do apologize, I am still a newbie. I have done just that and seems fine now.

 

[magpens]

Glad you got things sorted out, Mike. .

As you have discovered, there's a correct order for putting jaws in. . They should be numbered, with matching numbers on the chuck body.
After you have the first jaw so that it is "just catching", you have to place the second one in position and hold it in as far as it will go so that it gets "caught" at the right point while you are turning the knurled ring.

 

[Madman1978]

Update: I did get this worked out and TY for all your assistance.

 

[monophoto]

Michael

Glad to see that you solved the problem, but for the benefit of the next person who has this problem (and to be honest, almost all new turners eventually encounter this issue, and some of us seem to do it frequently) -

There are two concerns with four-jaw scroll chucks. One is that on most chucks, the jaws are are not 'universal', but rather are intended to be installed on specific sliders. Most four-jaw chuck manufacturers number stamp numbers on both the chuck sliders and on the jaws to help get parts into the correct places. I believe that Vicmark may be the exception to this generalization, but can be sure because I don't have a Vicmark chuck.

The other issue is the point made by both Herman and Mal - there is a spiral inside the chuck that 'drives' the jaw sliders. There are grooves machined on the underside of the sliders that match the spiral, and if the sliders aren't installed properly, they will be in the wrong sequence on the spiral. Ideally, you would never remove the sliders and therefore never get them out of sequence, but ideal and practical don't play well together; eventually, the sliders do have to come off so that you can thoroughly clean the chuck,; getting them back on in the right order can be tricky, and there are multiple ways to get it wrong. Unfortunately, I've never seen a written discussion of how to do this (possibly because it is hard to describe), and I've always had to fumble a few times before getting it right. But way to know that you have it right is to watch what happens as you close down the chuck until the sliders meet in the center - if all of the sliders arrive at the center at the same time, then they are installed correctly. On the other hand, if one arrives at the center before the others as you are closing the chuck, there's a problem.

You appear to have been working with a specialty pen-blank chuck which is the same basic design as a four-jaw scroll chuck except that it only has two sliders. As a result, there are only two ways to mount the jaws - either right or wrong.