# Smaller chuck vs a collet closer assembly



## jduncan (Jan 20, 2013)

Hi Guys,

I've got my three jaw which measures in at about seven inches across.  I'm probably going to be doing some fairly small stuff in the sub inch range.  Do you guys get a smaller chuck or just go for a collet closer and 5C stuff?  I though about making one myself as a good project but there don't seem to be any plans out there.  A smaller chuck would probably require me making a backplate to fit my threaded spindle...

Any opinions?


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## Jeff in Pa (Jan 20, 2013)

A collet would give better concentricity but how critical is that for the pieces you're making?


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## atwatterkent (Jan 20, 2013)

Your 13" SB should have a 1 3/8" dia ID through hole so a standard 5C spindle collet adapter & drawbar  is all you should need to handle pieces up to 1 1/8" dia., (as large as 5C collets come). A collet chuck should not be necessary. 
And yes, as Jeff in Pa said, collets are much more concentric and have repeatability which you will not have with a 3 jaw chuck.


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## jduncan (Jan 20, 2013)

I don't need super accuracy as I am only making gadgets for myself.  But I like the collet system so I am going to look into making my own adapter and drawbar.


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## cuseguy (Jan 22, 2013)

Collets are the only way to go for small work. Once you get used to them, you won't look back. A good 3-jaw is still irreplaceable for holding threaded, burred or non-conforming size stock. So it pays to have both. I have learned the hard way to not skimp on chuck quality 

Sent from my Samsung Galaxy Note II using Tapatalk.


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## Ray C (Jan 22, 2013)

Question to the OP:  When you say "smaller chuck", do you mean a small collet chuck?  Collet chucks usually come in 4 or 5".  They only hold a 5C collet and there's no advantage to getting the 5" as the 4" holds the same collets which (as someone already said) only go up to 1-1/8".  The 5" variety are usually a little cheaper for some reason.  I got mine from Shars and it's dead-on accurate and concentric (but maybe I just got lucky).

With collets, folks typically only hold clean stock in them as scaly/rusty stock could damage the lips and blow their accuracy -especially if you spin-out.  They're great for small work.  I highly recommend eventually getting a full set in 1/64" increments.  If you try to close down a collet too far, it could damage it or make it difficult to remove from the chuck.

Collets are my first choice for most things with spinning between centers taking second place.

Ray


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## fastback (Jan 23, 2013)

Given the choice collets are the most accurate way to go.  The one thing to keep in mind is you want the material to be only a couple of thous +/- or you can ruin the collet.   The nice thing about collets is you can get up close and not worry about moving chuck jaws.  The other nice thing about collets is that many will allow you to install collet stops for making duplicate pieces.  You do need the proper collets that have the internal threads.  


I have 5C on my heavy 10 and 3C's on my 9B.  As Ray said the set that go to 64ths are the best sets you get more flexibility.


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## jduncan (Jan 23, 2013)

I was thinking of a smaller four or three jaw but it's obvious that I need to make a collet adapter, not a collet chuck, and a drawbar.  Much simpler.  I just need to save up for a set of collets so I can machine the adaper to fit my spindle.

I remember last fall when I got this lathe, I read about how you'll spend X amount more than you spent on the lathe on tooling.  I'm not there yet due to budgetary issues but I will be eventually!


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## GaryK (Jan 23, 2013)

jduncan said:


> I was thinking of a smaller four or three jaw but it's obvious that I need to make a collet adapter, not a collet chuck, and a drawbar.  Much simpler.  I just need to save up for a set of collets so I can machine the adaper to fit my spindle.



For the perfect drawtube get some of THIS
It's perfect ID and OD. You can cut the thread on the ID without even having to open it up. I just did it and it couldn't be easier.


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## jduncan (Jan 23, 2013)

GaryK said:


> For the perfect drawtube get some of THIS
> It's perfect ID and OD. You can cut the thread on the ID without even having to open it up. I just did it and it couldn't be easier.


Great!  Thanks for the tip....off to order some now.


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## jduncan (Jan 23, 2013)

Before I order the tubing, what steel should I get for the collet adapter and spindle thread protector?  12L or something else??


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## GaryK (Jan 23, 2013)

jduncan said:


> Before I order the tubing, what steel should I get for the collet adapter and spindle thread protector?  12L or something else??



For the collet adapter I think I would just look for one on ebay. For the thread protector anything will work, even aluminum.


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## atwatterkent (Jan 24, 2013)

In a pinch you can use a face plate or dog driver as a thread protector.


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## OrangeAlpine (Jan 24, 2013)

Obviously, a lot of guys here disagree, but I have zero use for 5C collets.  I have none, plan to have none.  Their holding range is abysmal and I seldom work to fractions if the job does not require it.  Something you should consider if you have similar habits.  If precise rechucking is required (I plan my Order of Operations to avoid it), I bust out the 4 jaw and test indicator.  

Maybe ER collets, even though they are not rated for holding stock.  At least they will hold something that is a few thou undersized.

Bill


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## jduncan (Jan 24, 2013)

There's nothing wrong with a different opinion.


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## SE18 (Jan 28, 2013)

follow on question: you say with smaller chuck you'd need to make a backplate. I don't think so. Why not just stick a small Jacob's chuck on a MT2 taper and put that into the spindle. The only thing else you'd need is a $15 spindle adapter from Tools4cheap that converts the MT2 to the specialized MT3 of the spindle (not a true MT3 as it's shortened).





jduncan said:


> Hi Guys,
> 
> I've got my three jaw which measures in at about seven inches across.  I'm probably going to be doing some fairly small stuff in the sub inch range.  Do you guys get a smaller chuck or just go for a collet closer and 5C stuff?  I though about making one myself as a good project but there don't seem to be any plans out there.  A smaller chuck would probably require me making a backplate to fit my threaded spindle...
> 
> Any opinions?


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## swatson144 (Jan 28, 2013)

Funny you should mention Jacobs chucks. I actually have one that will fit a 1 1/2" x 8tpi spindle. It screws right on to my 9x20 so i don't bother with collets on it.

Steve


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## wa5cab (Jan 28, 2013)

One application where collets work and 3 or 4 or 6-jaw chucks don't is on thin wall tubing.  The chucks will deform the tubing.

I'm not up on SB lathes but popped in here to read the thread on chucks versus collets.  However, two of the posts don't seem to jive.  John, who started the thread, has a footer that says he has a South Bend CL145C 13x72.  Someone else wrote that that should mean his spindle is 1-3/8" bore (and thus large enough to pass a 5C drawtube instead of having to use a front mounted collet chuck in order to use 5C collets).  Then someone else said that he could use a Jacobs style chuck on a 2MT arbor with an adaptor sleeve to fit the stub 3MT taper, by which I assume he meant the spindle nose taper.  3MT, whether stub or standard, is considerably smaller than 1-3/8" in diameter.  What's the deal?

Robert D.


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## 8ntsane (Jan 28, 2013)

wa5cab said:


> One application where collets work and 3 or 4 or 6-jaw chucks don't is on thin wall tubing. The chucks will deform the tubing.
> 
> I'm not up on SB lathes but popped in here to read the thread on chucks versus collets. However, two of the posts don't seem to jive. John, who started the thread, has a footer that says he has a South Bend CL145C 13x72. Someone else wrote that that should mean his spindle is 1-3/8" bore (and thus large enough to pass a 5C drawtube instead of having to use a front mounted collet chuck in order to use 5C collets). Then someone else said that he could use a Jacobs style chuck on a 2MT arbor with an adaptor sleeve to fit the stub 3MT taper, by which I assume he meant the spindle nose taper. 3MT, whether stub or standard, is considerably smaller than 1-3/8" in diameter. What's the deal?
> 
> Robert D.



I was reading the thread as well, and Im still not sure of what spindle size he has. Though some machines are easyer to set up for a collet chuck, as some need a nose protecter built as well. I suppose it really depends on what method fits the machine too. Myself, I don't have any issues getting up close and personal to spinning chuck jaws. The 4-jaw seems to work fine for me . Maybe thin wall tube would be better in a collet, but its rare for me to be machining that stuff. The collet setup would save you from dialing in every part, and save you time there. But if making several of the same parts, then I would think collets would be best. If you had a depth stop in the mix, even better.


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## jduncan (Jan 29, 2013)

It has the large bore spindle, threaded 21/4 x 8.  So I believe that it has 1 3/8" through the spindle?  If a 5C collet will fit in there with no adapter, I just need to make a thread protector.  I haven't been clear on what's required for using 5C collets on my lathe anyway.


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## wa5cab (Jan 29, 2013)

OK. For collets shaped generally like the 5C (which excludes ER) and for collets with a through-hole that you can pass long pieces of stock through (which excludes R8, 2MT, 3MT, etc) You can use either a collet chuck front mounted on the spindle nose or a closer adaptor and draw tube. The latter is usually cheaper.

The OD of the adaptor usually fits the spindle nose taper (whatever that is) and is not keyed or threaded. The ID fits the OD of the collet (probably 5C in your case) including taper and usually has an anti-rotation pin. The draw tube OD must fit through the spindle bore, The ID is approximately the minor diameter of the threads on the outside of the collet and is threaded to match the collet threads. The left end of the drawtube may have a hollow handwheel attached, with usually a thrust bearing and spacer tube whose nose pilots into the left end of the spindle to hold the drawtube centered in the bore. This is the least expensive version. The length of the draw tube and length of the spacer and thrust bearing (which may all be one piece) is such that with the collet inserted into the closer adaptor, you can make up about 8 threads before you actually begin to compress the collet. Anyone who has such a setup for 5C might confirm the 8 threads is OK. I have an Atlas and that's the approximate number I use for 3AT and 3C collets.

It is usually recommended that you use a spindle nose thread protector, although that isn't technically required to make the collets work.

Robert D.


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## swatson144 (Jan 29, 2013)

1st and foremost let me say I do not have a southbend. I am putting this up as a (hopefully) help in picturing a typical collet and screw type draw bar set up. My spindle nose has a 5mt taper which is very common. Unfortunately many older lathes have something a bit more proprietary like a 4 1/2 short MT etc. Being the 5mt is so common I was able to pick it up from grizzly.




Basic parts are as previously mentioned. very bottom Left (with carriage bolt) is a home made collet stop, above that (at pencil tip) is the 5MT to 5c spindle/collet adapter, above that is the 5C collet at the end of the drawbar, Top left is the homemade spindle protector with spindle dummy.

on the handwheel end of the drawbar, note the flange marked with R this fits into the outside end of the spindle with the smaller diameter inside and the step as a flange against the spindle end. This piece rotates on a thrust bearing to ease tightening.




on the other end


Adapter with collet and spindle protector. Often the adapter has a larger flange and the spindle protector can be used to remove it.  Not so with my 5c adapter but the one for W25 collets works that way.  The 5C I just knock out with a brass rod.

There is also a lever type closer that may be available for your southbend but it'll be pricey.

Steve


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## atwatterkent (Jan 29, 2013)

Here's what the spindle collet adapter and thread protector look like on an SB.


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## jduncan (Jan 30, 2013)

Wow, great info guys!  I'm collecting the materials I need to make the drawbar, adapter and spindle protector now.  Thanks!!


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