# Looking for 8" or 12" 3 0r 4 jaw chuck



## COMachinist (Apr 8, 2014)

Hi All 
I'm looking for another chuck and I don't know if it is worth trying to find a good used chuck with 1 1/2 8tpi backing plate. Or if it is worth buying a Shars with the backing plate? We don't have a lot used stuff out here in Colorado. Most of that stuff has left the country and there is no new industry here. When they found out that they can blow the top off the mountains and heap leech the crushed rock to get the gold out, they don't need usable size tools any more for the home shops. Sorry I digress.  I have looked at several new chucks Buffalo new and used, and several older chucks of good quality. Then I came too after the sticker shock. The lathe only cost 1500.00 with all the tooling. I 'm finding it hard to fork over 900-1000.00 for a chuck. I know you get what you pay for, and there is nothing like great tools. The Shars have me scared a little they say 3.9 thou TIR I need better than that I'm wanting to bore some bearing races in some brackets, and want good fitting races.
Sorry about the long winded post but I really need some advice from a lot more experienced hobby machinist than I. All comments accept with appreciation and humility.
Thank for reading
CH


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## wa5cab (Apr 9, 2014)

CH,

I don't know what make or model of lathe you have but just about any of the Clausing, Colchester or LeBlond lathes mentioned here if new today would be well over $5000 with no accessories or tooling.  Even 30+ years ago, my Atlas 3996 with no tooling, accessories & no motor was about $2000.  So $1000 for a new decent quality US made chuck is no surprise.  I think we've become accustomed th the prices of cheap Chinese machines and accessories.  But I digress.  

If you need anywhere near .001 or better TIR and the part is too large for a 5C collet, you need to use a 4-jaw chuck.  I would probably buy a (high-dollar when new) used US made 4-jaw with two-piece jaws.  And if necessary, buy new jaws for it.  Or bore grind the old ones 

Robert D.


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## COMachinist (Apr 9, 2014)

wa5cab said:


> CH,
> 
> I don't know what make or model of lathe you have but just about any of the Clausing, Colchester or LeBlond lathes mentioned here if new today would be well over $5000 with no accessories or tooling.  Even 30+ years ago, my Atlas 3996 with no tooling, accessories & no motor was about $2000.  So $1000 for a new decent quality US made chuck is no surprise.  I think we've become accustomed th the prices of cheap Chinese machines and accessories.  But I digress.
> 
> ...


Hi Robert
Would you buy a independent or scroll self centering 4 jaw chuck? Oh and by the way I have  real nice Clausing 100 mk3 I picked up because I don't like buying Chinese. So yes I don't mind paying more for US made stuff. For the most part my Clausing lathe will do me with the 6" made in England chuck. It is stamped with a part number but can't make out the name. It is a very well make chuck and I like it a lot. I have fallen in love with the little lathe already and I have only had it for a month. Smooth quiet with a good old solid feel not that cheap Chinese rattle junk. The lathe is as old as I am and we fit great together.:thumbsup: I have an 8" independent 4 jaw but it is a major pain to get parts swapped out if you are doing more than one. I don't really need .001 TIR but I would think you should have some thing less than .004 TIR on a new Chuck right? Of course I'm not a master machinist and just a hobby guy, retired old hobby guy. What I need is to bore bearing races in my John Deere tractor front wheels because the bushings don't last long. So my thought was to dismount the tire and chuck the little 10" wheels in the lathe, bore out races to put ball bearing in them. The 6" chuck just wont get a grip on the wheel. By the way thank you for the input.
Have a good day:thanks:
CH


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## wa5cab (Apr 9, 2014)

Sorry.  I forget that there are a few scroll type 4-jaw chucks available.  I've never seen any general use for them.  Unless you do a lot of square or octagonal parts.  I meant the normal or independent type.

The Clausing 100 Mk3 is a nice machine from what I can see.  Probably a very good find at $1500.

Yes, Last time that I checked my 6" 3-jaw Pratt-Bernerd it was a little worse that 1-1/2 thou TIR.  And it hasn't been adjusted in at least a decade.  So one might hope to expect better than 3-1/2 out of a new chuck.  However, the spec could be at least part CYA.  I.e., considering their served market and the general level of expertise therein.  

But now that you've explained what you want to do (and I assume that you don't have a large number to do, either), what you need is a 10" independent 4-jaw unless the wheels have a smaller dia. machined reference surface in which case your 8" would probably do.  But regardless of where and with what you hold the wheel, you need to true up on the presumably unworn bore that the original bushings fit.  And to do that you are going to have to have a 4-jaw.

Robert D.


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## rock_breaker (Jan 8, 2016)

I have a Clausing 100 MK3 and wonder about clearances on your lathe. As "wa5cab" said machined reference faces are required as is perhaps a larger 4 jaw chuck. IMO it would be wise to check clearance on the ways when the chuck jaws are holding the work. I haven't done this, but believe the opposing jaws on a 4 jaw could be set to 10" or your wheel diameter then measure the OD of the jaws and compare it to the swing on your lathe. Not trying to muddy the waters here but know from experience things get close quickly when the jaws extend beyond the chuck  OD.
Have a good day
Ray


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## wa5cab (Jan 8, 2016)

Good point.  I don't know about 10" wheels but I know that the OD of standard stamped steel 16" rims is larger than 16", around 17" as best I recall.


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## middle.road (Jan 8, 2016)

IMO an 8" or 12" chuck on a 1-1/2"-8 mount is going to get scary. 
That is a lot of mass. Most chucks I've seen in that range use cam lock pins.


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## stupoty (Jan 8, 2016)

I have an 8 inch chuck on my leblond, it's got a 2 1/8 " thread, i have to cradle my arm under it when im taking it off,  threads only 4 or 5 tpi so theirs lots of wiggle room luckily, it's very hevey.  Somtimes i put a bar in the jaws nice and tight so it cant fall of the spindle so easily.

You can get 4 jaws in light waight versions that are shorter and more cut out than normal, also they dont have the scroll so that helps with the waight

Stuart


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## rock_breaker (Jan 9, 2016)

My 100 MK3 seems to handle an 8" OK , have had 6" conveyor idlers in it, not a lot of weight though. Made wheels for a small bore cannon.
Have a good vday
Ray


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## COMachinist (Feb 5, 2016)

Hi All
I have been kind of laid up fro the past 3 months have a double hip replacement. Which I needed really bad. They where a month apart, and just able to stand at the lathe. I did find a nice looking Buffalo 8", it is heavy for sure but can't seem to get it run true lots of run out. .005-010. It is from old Commies days of Poland.  It was in the original wooden crate and from the looks of it never mounted to a backing plate. When I'm back to normal(100%) so I can lift things I will redo the backing plate and try to get it down to 2 or 3 thou.
Take care and Happy New Year.
Go Broncos.


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## jpfabricator (Feb 5, 2016)

Indicate the wheels on a verical mill and use a boring head.

Sent from somewhere in East Texas Jake Parker


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