Disassembling small 4-jaw chuck

[PaulR]

How do I release the pinions on this chuck so I can clean them? The four 'screws' on the back, which I assume stop the pinions from falling out, are threaded normally on the inside (no slot or socket at the bottom). I seem to recall the back of my old 4-jaw chuck was simply screwed on - the circular back plate with it's 4 legs could be lifted out and the pinions removed whereas the body of this chuck is one piece.

[gbritnell]

Most 4 jaw chucks have screws that match the jaws and Chuck body. I suppose a universal 4 jaw Chuck might have pinions like a 3 jaw universal  I'm not familiar with a scroll type 4 jaw Chuck. Could you take a picture of one of the jaws? Usually a 3 jaw universal chuck is made in 2 pieces, the body and the rear plate which screw together from the front face.

[PaulR]

Does this help?

[PaulR]

Ah, just searched on the part number and found this thread:

https://www.hobby-machinist.com/threads/3-4-jaw-independent-sanou-mini-lathe-chuck-k72-80.102646/

Looks like it's not an easy task. Maybe I'll just blast some air through it to clean it.

[redhouseluv]

I had a quick look at the small 80mm 4-jaw I have .......snap, same design! 

I've never noticed that before.......

[PaulR]

Yeah, makes it hard to clean. I don't want to make a puller to get them out as they probably won't stay put afterwards!

[Charles Lamont]

I think you use the threaded holes to pull the dogs out. They ought not to be really tight (but that does not mean they aren't) because the teeth or prongs should self-align with the shoulders of the groove in the screw. I would use a piece of tube (cut away to clear the backplate register), a thick washer and a bolt to form a puller. My Bernerd chuck has no holes in the back of the dogs, so they have to be tapped out using a small punch awkwardly from the front. (Posts crossed.)

[PaulR]

I would use a piece of tube (cut away to clear the backplate register), a thick washer and a bolt to form a puller.

Yes, that's exactly what I was thinking (after learning how it's put together in that other forum thread). It's only 3 months old so I don't want to risk trashing it just yet so I'll clean it as best I can without disassembling then maybe next time try taking it apart.