# 9x20 Lathe Chucks



## gmac (Aug 15, 2011)

I've recently acquired a Craftex CT039 9x19 lathe that I'd like to fit with a better 4 jaw independent chuck. My question is - what diameter? Web searches show a number of people going with 6 inch chucks and a few going with 5 inch chucks. For hobby use have users found that one works better than the other, any problems associated with certain diameters? My preference would be the six inch despite some feeling it is a little large. Any and all input appreciated. Anyone aware of Canadian sources (other than BusyBee) for a chuck adapter?

Cheers Garry


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## Tin Falcon (Aug 15, 2011)

I have a 9" South Bend my 3 jaw is a 5 and the 4 jaw independent is a 6"  Keep in mind that when you try to hold larger diameters the jaws stick out of the chuck. if the chuck is too big for the lathe the jaws may hit something. 
If you select a chuck that is too small it will not holds the parts you need it to. 
Tin


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## t_ottoboni (Aug 15, 2011)

I think 6" would be too large. You can't go wrong with the 5" one. I have a sieg C6 lathe and a 5" four jaw independent chuck. It fits just right in the lathe and has a great range to hold parts.


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## maury (Aug 15, 2011)

GMAC, I have a 9x20 lathe (as well as 2 other larger ones). I work almost exclusively with castings, so I find the 4 jaw independant chuck quite a useful tool. I have found some castings won't fit well
in a certain size chuck because of the odd shape. As a result, I have 3, a 4", a 5", and a 6". I very
rarely use the 6" as it's just too big for this lathe, opting to use one of my larger lathes when a 6" is necessary. I have also found the Bison chucks to be excellent quality for the price, of course they are somewhat more expensive than the bottom end.

On the 3 jaw chucks, I have the 4" and a 4" Bison. 

maury
www.lonestarengineworks.com


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## hdwrench1 (Aug 28, 2011)

HI Garry,
I recently bought a 5 inch plain back 4 jaw from Little Machine Shop and a M39 blank to mount it and it works very well on my 9 x 20
Cheers
Wayne


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## Chazz (Aug 30, 2011)

Having owned the same lathe for awhile now, I'd say stick to a 6". 

1. I think they will give you the most practical range. (mine is on the lathe 80% of the time)
2. At about ~25 Lbs that's about as much chuck I think you want to be pushing that .75HP motor to turn-not-burn.(not to mention you haaving to haul it off and on) 
3. Remember, this lath does NOT have a brake of any sort, now imagine the inertia of a 50Lb 8" chuck spinning at 1,000 RPM? Now imagine going for supper while waiting for the lathe to stop spinning. :big: Oh wait even better, imagine accidentally throwing the Rev-Off-For switch into the Rev position? 
4. What ever budget will allow concerning quality, yes I've used\bought flea bay and big box tooling but your chuck is not worth the "I'll-get-the-cheap-one-for-now" philosophy.
That's my 2 pesos.
Chazz


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## gmac (Aug 30, 2011)

Thanks to everyone for the input. I've been waiting for the paint to dry fully on the BB 9x20 and started re-assembly. I've been searching around for chucks and chuck adapters in the meantime. 

I've spoken to Busy Bee's technical staff who have recommended the 5" rather than the 6" chuck. This seems to fall in line with what's fitted to other similarly sized lathes (10x18 etc), seems you need to get to a 12x lathe to be fitted with the 6" chuck. They expressed some concern about the combined weight of the 6" chuck and it's adapter. They also advised that BB does not have an adapter for the plain back 5" and 6" chucks that would work with the 9x20. I may have to machine my own adapter (if I can find a cast iron source!) since I can't find a source in Canada (1.5" x 8 tpi spindle thread). There are USA sources but shipping costs are too high.

One consideration is that the 6" chuck cannot be spun over the cross-slide table, whereas the 5" can be (not by much though). I'm not sure how much of an issue this is in the real world though - any comments/thoughts?

Finances dictate that I'll be buying a Chinese chuck, the difference between the 5" and 6" chuck is only $15 at the moment so cost is not the issue in size selection. A Bison chuck would be nice but......that's $700, more than I paid for the lathe!

So at the moment my idea is to go with the 5" chuck, suffering with the 7" chuck that came with the lathe for the occasional large diameter aluminum workpiece.

Chazz - where did you find an adapter? You say ~25 lbs for the 6" Chuck, most of the plain back Chinese chucks I've seen are listed at 9 lbs. Which chuck do you have? 

Thanks again everyone.

Garry


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## Chazz (Aug 30, 2011)

Hi Gary, check out shars.com, Pg. 93 for their 4 jaw chucks, 6" = 20 Lbs and 8" = 32 Lbs. and Pg. 90 for the 1.5" x 8TPI Mounting plates. (they have to be trued up to YOUR lathe).

I've bought from these guys and haven't had any problems.

Cheers,
Chazz

P. S. I bought a Bison Chuck and adaptor from KBC (just a tad more expensive, BUT you get what you pay for, that is, less than .0006 run out)


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## steamer (Aug 30, 2011)

I wouldn't go above a 6" 

Dave


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## Sparticusrye (Sep 20, 2011)

I have a B2227L 10x18. I use a 5" 3 jaw and 4 jaw chucks. I find that the 4 Jaw gets close to the bed ways when turning bigger parts so a 6" might be a bit large.


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## gmac (Sep 20, 2011)

Just to close this out, I bought a 5" four jaw independent chuck. From Busy Bee - the finest China had to offer  . I felt that the 6'' was too much for the 9x20 given that much of my work for the four jaw would be with relatively small diameter stock (in the 3/4'' to 5" range). For the few occasions when I need a large diameter chuck I'll suffer with the 7" chuck that came with the lathe. Now to sort out an adaptor for the chuck - I think I'll just machine one up - another project!

Thanks again to all who took the time to comment, much appreciated.

Sparticusrye; Hello to another Nova Scotian! I was born in New Glasgow - parents from Cape Breton.

Cheers Garry


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