5C collet chuck question

blue_luke

blue_luke

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Hi all, this one is definitely in the newbie department. :)

While waiting for my machines and gathering tooling, I run often in 5C chuck and collet kit.

Someone recommended I get these but I fail to understand what they are for or rather, what is their advantages
in the context of a home machinist over the standard 3 jaws chuck.

I think I can conceive that a better concentricity is attainable, and also, in the context of a commercial shop
many parts can be manufactured from a long bar, saving time on setup.

So the bottom question is, should I get this, and why?

Luc
 
A collet chuck is also easier to repeatedly grasp a part with the same concentricity. It also will make it possible to grab very small/short parts that would not hold well in the jaws and perhaps use a spring ejector or workstop inside(to set depth od workpieces uniformly so you don't have to re-zero the knobs when making multiple pieces), as well as leave less marking than jaws when working with soft material. Another think I like about them is there is much less "hanging out" and there is a smoother outside diameter whick I feel greatly reduces the likelyhood of catching a sleeve,etc when having to get close. Look at this link and the first four subsections in the upper left corner and I'm sure youll get some more ideas . http://www.home-machine-shop.com/bits/index.htm I'm sure there is more, I love mine...Todd
 
An alternative to the 5C collet chuck (I own and use several ... also 2J) is an ER32 or ER40 to MT3 collet chuck.

Although the entire ER system is metric, not withstanding the fact that most ER sizes are available in fractional (Imperial) sizes (by 1/16-ths or 1/32-ths), rather than integral (metric) sizes, and the thread for the drawbar is almost universally Imperial. Indeed, for most small lathes, a suitable drawbar may be made from a commodity hex-headed bolt, 11" long in the case of my Logan 820.

Now, I initially went with an ER40 "set" from eBay seller "800Watt", at a VERY reasonable cost. But, I quickly expanded that "by 1/32" set to include ER16s, by both fractional (a mistake, in retrospect) AND by 0.5mm (metric).

The ER16 collet chuck is simply a standard 100mm long straight shank CNC collet chuck which has been cut-off to be about 1-7/8" from the shoulder. Just enough to fully engage a 3/4" ER40 collet with a tad to spare.

The TIR of the ER40 collet chuck is as close to zero on a DTI as one can get, and the same is true of the ER16-within-an-ER40.

I still have 5C and 2J, but the 5C is almost never used, and the 2J is used mainly in the larger sizes, particularly over 3/4" and up to 1-3/8".

Every shop is different. Just select the collet system which best works for you.

I still have a 5C scroll-type chuck in a 1-1/2"-8 backplate, of the type generally sold by CDCO and others, but it is very seldom used.

The ER40 is almost always found mounted in the spindle of my lathe, with the ER16 collet chuck and collets close by.

The ER16 is a good choice for Unimats, of which I own and use two.
 
Thanks guys!
It is quite clearer in my mind when I look at the home machine shop site!
Great site! in my favourites now! :)

But following one of the suggestions, I do have a set of ER34 collet for my mill with an R8 arbor.
I think my lathe uses MT3 ( Precision Matthews PM1127vf) http://www.machinetoolonline.com/PM-1127-VF.html
for the headstock.
So it seems that just buying an MT3 arbor will get me by, am I correct?

If that is so, then I guess there is less of a need for a set of 5C.

On the other hand, I found there are hexagonal and square holders which I have never seen in ER34 system.

And also I found that 'emergency' collet in the 5C system to be very handy for some purpose I have in mind.
Do these exists in the ER34 series?
 
blue_luke said:
Thanks guys!
It is quite clearer in my mind when I look at the home machine shop site!
Great site! in my favourites now! :)

But following one of the suggestions, I do have a set of ER34 collet for my mill with an R8 arbor.
I think my lathe uses MT3 ( Precision Matthews PM1127vf) http://www.machinetoolonline.com/PM-1127-VF.html
for the headstock.
So it seems that just buying an MT3 arbor will get me by, am I correct?

If that is so, then I guess there is less of a need for a set of 5C.

On the other hand, I found there are hexagonal and square holders which I have never seen in ER34 system.

And also I found that 'emergency' collet in the 5C system to be very handy for some purpose I have in mind.
Do these exists in the ER34 series?
Click to expand...

I have found that MT 3 collets want to bind in their bore because of the slow taper where a 5C with it's different taper characteristics will release more readily. Also because a MT3 has a drawbar arrangement instead of the outside drawbar arrangement of the 5C you are limited in length whereas a 5C allows you to run a long bar through it easier.

Hopefully I didn't miss anything or misstate anything ?

I'm currently working (have bought the materials) on building my own 5C chuck. That being said don't look for anything soon.

~Chris> Tenn
 
"I have found that MT 3 collets want to bind in their bore because of the slow taper where a 5C with it's different taper characteristics will release more readily. Also because a MT3 has a drawbar arrangement instead of the outside drawbar arrangement of the 5C you are limited in length whereas a 5C allows you to run a long bar through it easier."

A shop-made ER-whatever is a simple thing to do. There are quite a few plans available on the 'Net. You can make your own closing "nut", or you can use a factory-made "nut" IF you can thread in metric.

This will give you through-hole capacity up to the I.D. of your spindle, often 3/4" for small engine lathes.

The CDCO-type collet chuck also gives you this. Check around on the price. It can be as low as $139.

As does the Century-old Sjogren "Speed-Chuck", patented in 1929 by a machinist, a Mr Sjogren in Los Angeles, but marketed for many years by Hardinge Inc, but presently marketed by ATS Workholding. But, these can cost $1,500, new.

One advantage of the 5C system is the availability of so-called "emergency" collets, with which one can make all kinds of specialized workholding devices. And a large number of super-precision devices are made using only 5C "emergency" collets as their sole workholding.

Also, so-called "pot" collets, with which one can hold very large diameter, but rather thin workpieces. A favorite of the optical industries.

No, there is not one truly "universal" collet system.

Only one which is capable of performing MOST, but not all, of your machining operations.

Which maybe why I own and use 5C, 2J, ER40 and ER16 systems.

Yes, I also own 3J and 22J "Speed-Chucks", but no collets for those.
 
5C collets.

These are great for highly accurate holding of round, Square and Hex parts in a lathe, and on other machines using that collet system, spindexers, collet block for quick and dirty indexing etc.

On production machines with lever type collet closers, and stock stops, the collet can be realeased and the stock fed without even turning off the spindle for the lathe, (Don't ever try that with a 3 jaw chuck or an ER collet!)

5C collets used with drawbar collet closer, either handwheel of Lever mount inside the spindle and use little to none of the centre to centre distance of the lathe. Nosepiece mounted collet closers are much like a chuck in that they move the work further from the headstock nose.

Emergency collets and soft collets are available which can be machined by the user to fit specific applications. Also available as expancing mandrels and you can even get 3 jaw chucks with 5C mounts.

5C collets are generally though hole collets so if used in the headstock of the lathe, long stock can be fed through the bore of the spindle.

Disadvantage is that grip range is very limited and so you need many collets to cover the range from 1/32" to 1-1/8". Something to the tune of 71 imperial, then the metrics and then the Squares and Hexs. So lots of pieces.

ER collets are only available in round sizes but 23 collets cover the range from 1/8" to 1"

ER collets can be used in the headstock, and tailstock of a lathe and can also be used as a tool holder collet for a milling machine. 5C collets are not used in milling spindles or tailstocks of lathes that I have seen
.
Now if you use a MT to ER adapter in the headstock of your lathe, you loose that through hole capacity that the spindle bore is for. You can do this and if you are working on short stock, you get the benefits of high collet accuracy and limited number of collet changes.

The better route for a lathe is to make or invest in a nosepiece mounted ER collet chuck. Like the 5C nosepiece mounted collet chucks, they use up some room in the lathe and move the workpiece further from the headstock spindle nose.

Hope this helps

Walter
 
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