Buck 4 jaw chuck conundrum, assembled wrong by someone.

[J Tiers]

This is evidently a decent chuck. and it works OK. But there are some issues.

1) two of the screws are too long and stick out (more on that)

2) There are three versions of jaw in the chuck, although all are the same size, they fit and work fine. (more on that also)

3) The chuck is assembled with some sort of melted metal poured in to hold the screw "forks"., possibly solder, wood's metal, etc (not unusual)

.
The problem is that I do not like the screws that stick out. And, it appears that those screws may affect the holding of smaller work, as well, since they also do not stick IN as far. Those screws have a different "fork" than the others.

The two that stick out appear to be backward, in that they should fit correctly if turned around. That of course would mean disassembly.

The jaws, while nominally the same, have different numbers of threads. Two have 9 threads, one has 10, and one has 11. There is no particular evidence that there were any threads cut off.

So, I am contemplating disassembling the chuck, reversing the two long screws, and re-assembling it.

How bad an idea is this? I have worked on many chucks, but never the type that have the melted metal filling. I don;'t know if it is typically a low melt alloy, or something like zamac, etc.

[eKretz]

Weird. Maybe try melting one of them and see if it comes to liquid at a reasonable temperature? Take care to capture it and maybe it can be reused. I wonder if the jaws are such that they can also be used in one of those scroll/independent chucks?

[psomero]

if you drilled the melt stuff, presuming it's a plug in a straight bore, could you yank it out with a screw?

that is odd that they all have different number of thread teeth.

[SVS]

Do the screws have a drive socket on each end?

[Canus]

Are the jaws and chuck slots numbered?

[Rich Carlstedt]

Jerry, you had it right !
Someone (re-) assembled the chuck with parts from other chucks
that's a very very old Buck Chuck , so no doubt it has had some repair sessions in it's history
You can see the even older version here

https://www.practicalmachinist.com/forum/threads/wtb-jaw-s-for-buck-logan-444-6-4-jaw-chuck.190300/

Rich

[J Tiers]

Do the screws have a drive socket on each end?

If they don't they will have......

[SVS]

If they don't they will have......

Question was directed towards the reverse installation vs. Franken-chuck question.

WARNING-your project list might grow to include a rotary broach….😁

[JRouche]

I say BS Jerry, I think its cracked. I dont know. JR

[JRouche]

My favorite chuck is a four jaw. Really easy to set up, with help. I had help. JR

[djc]

Could you remove the forked plugs from the long-screw positions, fill the hole and reform it closer to the chuck centre so everything sits flush on the outside?

If there is enough wiggle room, just make a new plug with an offset fork and reuse the old hole.

Modify the screws. Make the shoulder longer towards the outside and put a spacer ring on the gap that will be created on the inside.

[J Tiers]

Question was directed towards the reverse installation vs. Franken-chuck question.

WARNING-your project list might grow to include a rotary broach….😁

Same answer.

No rotary broach. Maybe an EDM........😉

A lot will depend on the forks. They may be off-center / reversible, which would potentially allow the screws to move inward. The two "good" screws have a wider fork, suggesting it is possible. Some measuring should show what's up with that.

Making new forks is also well within the realm of possibility. All of this is future, I need to finish a bunch of other things first.

[J Tiers]

Hah..... That was easy.....

They are not drillable, but there is a reason..... They are basically welch plugs! They may actually BE welch plugs. All I had to do was pund a chisel into them, and then pop them out. They are about 0.062 thick x 0.75, and I may have some in the kit out in the shed..

Not actually much help, because the forks are already oriented to put the screws as far in as possible, and there is not enough left on the forks to allow making one with the fork sufficiently farther over.

Flipping the screw is, of course perfect, but I need to EDM the square holes, the screws are hard. I'm not set up to do that at the moment, but I could rig an EDM up that would be manually operated.

[old mart]

Strange that 4 jaw chucks are popping up with odd or custom parts. Back on the 10th Jan, Lalkie started a thread about his 4 jaw scroll which has missmatched jaws.

[J Tiers]

I've had this one for an un-remembered amount of time. Not even sure where it came from. It's been annoying me for a while, and I decided to investigate it when I had to take it off the "positioner" (which it turned out I could not use for the intended purpose).

So it is not some cosmic alignment issue, I just happened to have to notice it recently. I have too many 4 jaw chucks right now, maybe, although one of them goes with each bigger lathe. I do not have any "chucks" for the small lathe other than what used to be called "wire chucks", i.e. collets.