# Opinions on chuck size



## Terrywerm (Oct 20, 2014)

Contrary to popular belief, size does matter!!  I've got a Logan 210 lathe. Nothing special about it, it is the standard machine with the 1 1/2"-8 threaded spindle, 24" between centers, and so on. When I bought the lathe the previous owner threw in a 5" Cushman 3 jaw scroll chuck that had been severely damaged at one point in its life. The jaws have been added to by welding on some stock, then grinding down, the body shows signs of extreme damage, and a number of other transgressions. I knew that it would need to be a temporary member of my stable, and I use my 6" 4 jaw anytime I have to do something that needs some real accuracy, dialing in the stock each time to get it centered up. 

Anyway, I am now at the point where I am getting ready to purchase a new 3 jaw chuck and backplate for this lathe. I briefly considered a used chuck, but most of those that I find do not appear to be much better than what I have, the second set of jaws is usually absent, and the price is darn near that of a new chuck.  

So, I am looking at chucks and I am thinking that I might like a small chuck at some point in the future for doing small work, let's say a 3" or 4".  There are times when a 6" chuck would be really handy too. So I am thinking about purchasing a 6" three jaw chuck now, and maybe a 3" chuck later. The other option is just to stick with a 5" three jaw for this machine and go from there.

So the questions are as follows: *Have any of you gone to a 6" three jaw chuck on your 10" lathe?   If so, what problems do you encounter??  Do think maybe you should have stayed with a 5" chuck, or is the 6" the way to go?*

I am looking for opinions here, good and bad so I can make a proper decision. I am leaning in the direction of a 6", but I can see the advantages of sticking with a 5" also. 

Let's hear what you've got to say, gang, I'm all ears!


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## GK1918 (Oct 21, 2014)

Good question, I think I lean more to a 6 inch unless you are machining a needle.  I mean by that Is, my GK has a very expensive Rohm 10" 3 jaw & is on the boarder with maybe a
1/4 part chucked up, but we dont use this lathe for smalls.  Then on the S Bends we run 8" 4 jaws. Guess its a toss up,  but I think a 6" is more  versitile.  Myself I never got along
to well with 3 Jaws but, the Rohm I got, kind of rules, but ya gotta take out a loan for one.
sam


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## Rbeckett (Oct 21, 2014)

I'm thinkin you are on the right road with a 6 inch 3 jaw and buying a 3 or 4 inch chuck lster on for smaller items we tend to make with our smaller machines.  So it is just my opinion, but I do think you have the right approach already  figgered out.

Bob


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## chuckorlando (Oct 21, 2014)

I dont know if it helps or not but it seems to me a 6 3 jaw and 8" 4 jaw is what most do on the 9x20 imports. Thats where I'll be heading for long as well


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## fastback (Oct 21, 2014)

I like having the 6-inch on my 10L Southbend. I bought a Bison with the 2 piece jaws new at a very low price.  This chuck does most every thing I need to do, for smaller work I use collets.  My lathe takes 5C's.  My 9- inch Southbend has a 5-inch Bison this is also a nice chuck.  I have thought about making a backing plate for the 5-inch so I can use it on the 10 inch machine, but I have not run into anything that has required the size change.

So to answer your question, I would go with your thoughts of the 6-inch and a smaller 3 or 4-inch for smaller work.

Paul


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## Redlineman (Oct 21, 2014)

Hey;

Logan does recommend a 6" max for these of course, to reduce/eliminate accidental jaw strikes. I would say that if you got a really good quality 6", You could obviate the need for a second smaller one. A nice 6-jaw would do it!


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## projectnut (Oct 21, 2014)

GK1918 said:


> Good question, I think I lean more to a 6 inch unless you are machining a needle.  I mean by that Is, my GK has a very expensive Rohm 10" 3 jaw & is on the boarder with maybe a
> 1/4 part chucked up, but we dont use this lathe for smalls.  Then on the S Bends we run 8" 4 jaws. Guess its a toss up,  but I think a 6" is more  versitile.  Myself I never got along
> to well with 3 Jaws but, the Rohm I got, kind of rules, but ya gotta take out a loan for one.
> 
> sam



I have an older 10" X 60" machine that is happy using anything from a 3" 3 jaw to an 8" 4 jaw chuck.  I have half a dozen 3 jaw chucks ranging in size from 3" to 8",  several 4 jaw chucks ranging in size from 4" to 8", and a 5C collet chuck.  All in all I select the chuck depending on the size of work I'm doing.  A 6" chuck is a good all around pick, but when working with small diameter stock (1/4" or less) I  prefer one of the smaller diameter 3 jaw ones or the collet chuck.  It's just easier to work around and doesn't require spinning an additional 25 - 40 lbs. of metal.


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## Inflight (Oct 21, 2014)

I have an 8" 3-jaw on my 10" lathe most of the time but also have a 6" 3-jaw as a spare.  The heavier (8") chuck adds nice mass and seems to help reduce chatter with the increased inertia.  If you are working on small diameter tasks often, then the little 3" - 4" would be good.  As others mentioned, the 5C collet chucks are a real time saver.


Matt


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## Falcon67 (Oct 21, 2014)

I have a 4" 3 jaw (stock) on my 9x20 and a 5" 4 jaw in the drawer.  The 3 jaw is surprisingly accurate.  I have used the 4 jaw a few times but the 3 stays on the lathe pretty much all the time.  I haven't seen a need for anything larger.  Anything heavy that approaches the max holding size of the 3 jaw is pretty much getting close to exceeding the lathe and chuck's ability to hold and machine the item.


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## brav65 (Oct 21, 2014)

I have been told by many women that men lie about their chuck size regularly:rofl:


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## Whyemier (Oct 21, 2014)

brav65 said:


> I have been told by many women that men lie about their chuck size regularly:rofl:


e


Glad he wrote that' we all thought it. I've been told "Size don't matter" by my wife and she wouldn't...O gee!:sorry3:


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## Terrywerm (Oct 21, 2014)

Thanks for all of the opinions, gang, I really do appreciate you all taking the time to share your thought and experiences. I do have a full set of 3AT collets for this machine, and I use them when working on small stuff if the parts are not too long. I am planning to make an ER32 chuck to fit my spindle, which would allow me to use collets for long stuff too. If I do that I may not need a small 3 jaw and the 6" 3 jaw would be sufficient. I also have a 6" four jaw (maybe I already mentioned that) but I can see where an 8" might be nice once in a while.


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## projectnut (Oct 22, 2014)

terrywerm said:


> Thanks for all of the opinions, gang, I really do appreciate you all taking the time to share your thought and experiences. I do have a full set of 3AT collets for this machine, and I use them when working on small stuff if the parts are not too long. I am planning to make an ER32 chuck to fit my spindle, which would allow me to use collets for long stuff too. If I do that I may not need a small 3 jaw and the 6" 3 jaw would be sufficient. I also have a 6" four jaw (maybe I already mentioned that) but I can see where an 8" might be nice once in a while.



I purchased my first 8" 4 jaw chuck for a special project.  It's been so long I don't even remember the project.  The thing is so massive I'll bet it weighs nearly 50 lbs.  It's great for larger stock, but it's a lot of weight swinging around  on a small spindle.  A couple years later I found a used 8" 4 jaw LW chuck that weighed about 1/2 what my original one weighed.  I find I use the LW more than any of the others.  Mostly because of its capacity and ease of dialing it in.


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## CNCMAN (Oct 28, 2014)

On my 1922 Logan I have a 5 inch 3 jaw. Mine is strictly hobby only but I was concerned about the extra weight wallowing the back bearing (don't ask me how I know):angry:. 
It also has the 5c collet closer but i never really use it. 
Just my 2 cents.
Kevin


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## wa5cab (Oct 29, 2014)

This thread started out with a question about what was the optimum size 3-jaw chuck for a specific model lathe.  But has diverged a bit.  One type of chuck that hasn't been mentioned can be handy if your main (or smallest or only) chuck is say 5"  or 6", you don't have a full collet set, or you only have one small part to do and don't want to set up the collet closer.  This is what Jacobs called a Spindle Chuck.  It looks like a large drill chuck except that instead of being mounted on an arbor, it is threaded to screw onto the spindle.  Handy for some small parts.  Jacobs made four that I know of.  

55B threaded 1"-8, holding range 1/16" to 17/32".

56B threaded 1"-10, holding range of 1/16" to 17/32".

58B threaded 1-1/2"-8, holding range of 1/8" to 5/8".

59B threaded 1-1/2"-8, holding range of 3/16" to 3/4".

I don't know what happened to the 57B.  If it was 1-1/2"-8 with a 1/16" to 17/32" range, then I am looking for one.

I have the last three.  As with collets, they are just inherently safer or more comfortable to work around with very small parts.

Robert D.


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## Terrywerm (Oct 30, 2014)

Thanks for the tip on the Jacobs spindle chucks, Robert.  I always knew that they had been made, and I see them on eBay from time to time, but for some reason left them totally out of the picture!!!  I am really glad you brought them up. One of those and a 6" three jaw should work out just about perfect!


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## wa5cab (Oct 31, 2014)

Terry,

I forgot to mention that at least each of the four that I listed are open through with an ID of about the maximum chuck capacity.

Robert D.


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## Mister Ed (Dec 5, 2014)

Terry, Did you ever get your new 6" chuck? What are your thoughts, if you did.


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## GarageGuy (Dec 6, 2014)

I plan to buy a new 8" 3-jaw, and a new 8" 4-jaw for my Logan 10".  My current chucks are also very old and worn.  It's hard to imagine what a new chuck with tight tolerances will be like  :biggrin:

GG


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## wa5cab (Dec 6, 2014)

GG,

8" chucks are a bit too large for a 10" machine.  You can easily run the jaws out far enough to strike the bed.  Plus any decent 8" 3-jaw is going to weigh upwards of 40 pounds.  You will soon get tired of hauling that weight around.  Unless you only intend to work on very short parts, you can't swing much above 5" dia. anyway (not knowing what model you have, I don't know what it will swing over the cross slide but almost any 10" is going to be under 6" and probably closer to 5").  

Robert D.


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## GarageGuy (Dec 6, 2014)

I understand your point about jaw extension in larger chucks, and part clearance over the cross slide.  Up to now, my projects have been very short.  The biggest was turning a pulley out of 6" diameter aluminum that was 2 1/2" wide, and my current chuck was at it's outer most limit.  I won't be getting rid of my old chucks, but I do want to make sure I can get the biggest piece of metal possible chucked up in my machine.  Ideally, I would just get a bigger machine, but I don't have the space and probably never will.  An 8" may indeed be too big.  It would be nice to try one before I went out and dropped real coin on it, but I don't know anyone locally who has one that I could test drive.

Thanks for the tip,

GG


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## Terrywerm (Dec 6, 2014)

Mister Ed said:


> Terry, Did you ever get your new 6" chuck? What are your thoughts, if you did.



Yes I did, just last week, in fact. Problem is I was too sick to do anything with it!

Keep in mind fellas that my budget is pretty limited right now, so I ended up buying Chinese instead of something really nice like a Bison or Gator. I had considered just waiting until I could afford to purchase a better chuck, but I NEED something better right now, as the original 5" that came with the lathe is not much good for anything other than a doorstop. I've gotten away with the old clunker for a while, but I find myself having to use the four jaw quite a bit, and I would like something with easier repeatability.

This chuck is a very old Buck, with a single pinion, and has had major repairs done to it where a jaw broke out at one time in the past. It is stiff in some places, and loose in others, the jaws are for the most part loose in their slots, etc.  I could go on and on about what is wrong with it, but it would be a waste of time. I will let the photos tell their own story. The rust streaks you see are from a rusty pin that I cleaned up the last time I used the lathe, NOT from the chuck itself. I hate working with rusty material, but sometimes you don't have any choice.




I purchased a Shars 6", three jaw, front mount chuck with reversible jaws. It's quality is better than I expected, and it fit my current budget. Since it is front mount, it can easily be moved to my 6" rotary table and get mounted to an adapter plate on it. Eventually, when I can afford a 6 jaw adjust-true chuck, the Shars chuck can become a more permanent accessory for the rotary table.




This thing is massive compared to the 5" chuck, which seems odd when one considers that it is only 1" larger in diameter than the old one. I do like the fact that it has the oiler on the front, also. I did completely disassemble the new chuck to get the remaining grit out of it's innards (there was not much), and it is much smoother in operation now. I hope to get the backing plate machined today or tomorrow so that I can start to use the chuck. I will report back later on the chuck runout after I get it all mounted up.


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## Mister Ed (Dec 6, 2014)

Keep me posted Terry. I am in the market, I think. I still have the original Logan chuck, but only the reverse jaws and it is driving me nuts. Like you, I probably cannot justify a new US made chuck.


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## Terrywerm (Dec 6, 2014)

The Shars chuck is also available in a rear mount version.  Both versions list the total runout at .003", but the inspection card that came with mine indicates .0014 on this one, far better than I expected, and certainly within limits that I can live with.  The rear mount version is a bit less expensive as well, about $10 less than the front mount if I remember right.

If you do work with tubing from time to time, a six jaw chuck may be more to your liking.  There is a vendor on eBay that is offering a 6" six jaw with reversible jaws but is NOT an adjust true chuck. Here is the link:  http://www.ebay.com/itm/160828698511?_trksid=p2055119.m1438.l2649&ssPageName=STRK:MEBIDX:IT    I briefly thought about this one, but decided that a three jaw would be better for later use with my rotary table, thus I went that route. 

I will post more as I get to working with the new chuck and get it set up.


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## wa5cab (Dec 6, 2014)

GG,

Your 6" pulley would be fine on a 6" 3-jaw (or 4-jaw).  The largest diameter that you can run on a 10" lathe if the chuck grabs it on the OD is around 8-3/4" because the reversible jaws will add about 5/8" on the radius or 1-1/4" on the diameter.  Which is also on or maybe a little beyond the ragged edge of what you can run on an 8" chuck and still have enough teeth engaged to be safe.  So to run an 8" dia. part you really do need an 8" chuck.

However, my 6" Pratt Bernerd SetRite chuck on a 1-1/2"-8 back plate weighs 27 pounds.  According to the MSC catalog, the 8" equivalent weighs 46 pounds without the plate.  You don't want to be swinging that around.  So I would get a good or better quality 8" 4-jaw for the big stuff and something like my 6" 3-jaw for everything else.

Robert D.


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## Ebel440 (Dec 6, 2014)

One of the first things I noticed about my logan was the chuck. It's very short compared to other chucks.  I think it's the stock chuck and a lot of Logan's I've seen have the same type. I think that's why you notice a large weight difference.


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## wa5cab (Dec 7, 2014)

Ebel,

Yes.  The original Atlas 3-jaw chucks are quite short, as well.  I doubt that my original Atlas 6" 3-jaw weighs much over 10 pounds.  The Pratt is over twice as long, and has heavier jaws.  So, despite it having about twice the ID, it is over twice as heavy.  The equivalent 8" is about the same length  and has the same ID but weighs almost twice as much because the volume of a cylinder varies as the square of the radius.

The reason that independent 4-jaw chucks are usually shorter and lighter than the same diameter self-centering 3-jaw is that the 4-jaw doesn't have a scroll inside and aside from the grooves of the scroll, the 3-jaw is almost a solid cylinder except for the ID.  Typically, the back of an independent 4-jaw is not solid or flat.  In the back, a lot of metal is omitted in between the jaws.  At least on threaded-mount ones.

Robert D.


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## xalky (Dec 7, 2014)

Terry, If you've never used a chuck with 2 piece jaws, you're gonna love it. 

Get yourself a set or two of steel soft jaws for it too. I use soft jaws so much, that I don't know what I'd do without them. They're easy to customize for shallow parts and they don't mark up finished parts for instances when you have to turn a part around on a finished diameter, ID or OD. A must have IMO.)


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## Terrywerm (Dec 7, 2014)

xalky said:


> Terry, If you've never used a chuck with 2 piece jaws, you're gonna love it.
> 
> Get yourself a set or two of steel soft jaws for it too. I use soft jaws so much, that I don't know what I'd do without them. They're easy to customize for shallow parts and they don't mark up finished parts for instances when you have to turn a part around on a finished diameter, ID or OD. A must have IMO.)



That is kind of what I was thinking, Marcel. My old chuck is missing the second set of jaws as so often happens with used equipment. There have been a number of times where I wished I had them, too.  A set of soft jaws is definitely on the wanted list, and I have seen them in both steel and aluminum. In a worst case scenario, it probably would not be too difficult to make my own soft jaws.


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## wa5cab (Dec 7, 2014)

For the benefit of anyone new to the art who doesn't yet know, the "second set of jaws" which are usually called the outside jaws, refers to the fact that on most self centering chucks, you cannot physically turn the complete jaws around in order to for example grip the OD of a workpiece whose diameter is over about 50% of the chuck diameter.  This is because of the way that the truncated threads on the inside (hidden part) of the jaws are made.  So almost all less expensive self centering chucks originally come with two sets of jaws.  By the time that the chuck gets sold used, probably 80% of the time the other set has been lost.  If considering buying a used chuck with solid or one-piece jaws, always make sure that it comes with both sets.  Usually if it does, the seller will show them in one of the photos.  If none show in any photo, it usually means that they are MIA.

The other type of chuck jaws, usually found on more expensive chucks, are called "two-piece".  They have a set of master jaws that never come out of the chuck except for major cleaning.  And a set of hardened reversible jaws attached usually by two socket head cap screws.  The hardened reversible jaws can also be replaced with various types of soft jaws.

Robert D.


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## Terrywerm (Dec 15, 2014)

I finally got my new backplate machined and the chuck mounted to it yesterday and I must say that I am quite satisfied with the results. Tested for runout and it came in at .0012" with a .750" diameter test piece. I cannot complain about that!


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## MBfrontier (Feb 13, 2015)

Hi, Terry.

Did that Shars Chuck come with a chuck key? 

Mike B.


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## Mister Ed (Feb 13, 2015)

MBfrontier said:


> Hi, Terry.
> 
> Did that Shars Chuck come with a chuck key?
> 
> Mike B.


I bought one after Terry, chuck key included.


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## MBfrontier (Feb 13, 2015)

Thanks, Mr. Ed. Did you purchase the front or rear mount chuck?

Mike B.


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## Mister Ed (Feb 13, 2015)

MBfrontier said:


> Thanks, Mr. Ed. Did you purchase the front or rear mount chuck?
> 
> Mike B.


I ended up with the rear mount. Bought both chuck and back plate as a package. Back plate was pre drilled.


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## Terrywerm (Feb 15, 2015)

Sorry I did not reply sooner, I've been out of the loop for a while for a number of reasons, one of them being that I have been out of town for work for most of the last three weeks.  Anyway, Ed beat me to the punch, and was able to answer your question. Thanks Ed!

Like Ed, I bought both the back plate and the chuck at the same time. The back plate for mine was also pre-drilled, I only had to cut the register on the back to fit it to my lathe. Oh, and yes, a chuck key came with it, which is standard practice if I recall correctly.


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## MBfrontier (Feb 15, 2015)

Hey, Terry.

After reading this thread about your purchase I thought I would buy the same chuck but a rear mount including the back plate. It seems to be the biggest bang for the buck for what I need. I have an old 6 inch Cushman that is seriously worn and would cost more to restore than purchase a new import chuck. The run-out on yours was impressive. Thanks.


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## 4GSR (Feb 23, 2015)

I bought one of these chucks about ten years ago to put on my 9" SBL.  I will say it has been a very nice chuck to own.  I made the chuck adapter about .005" loose so I could adjust it to running dead true for my needs.  I think in the past ten years, I've only re-adjusted it once or twice.  Never had an issue with runout, always within .0005" or better! at most diameter up to around 1.500".  For a Chinese made chuck, not bad, but nice!


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