# Collet ?



## bisley45 (Dec 18, 2014)

If you had no collets and were going to purchase a set for your 9" south bend what would you get c3 or something else?


----------



## Andre (Dec 18, 2014)

My small bore 13" uses 2A.


----------



## rmack898 (Dec 18, 2014)

I think I would go for a 5C collet chuck and collets because of their versatility in other inexpensive fixtures around the shop. ( Like square and hex collet blocks)

I bought a cheap import collet chuck for a SB13 that I had and it was actually a very nice chuck for $130


----------



## Smithdoor (Dec 18, 2014)

It is the best to use the 3C for the 3/4" bore
I have same thing I also have set of 5c collet too. 
That when need some thing large I just use a four jaw and a simple 5 c collet hold take more time 

Dave



bisley45 said:


> If you had no collets and were going to purchase a set for your 9" south bend what would you get c3 or something else?


----------



## DoogieB (Dec 18, 2014)

If you feel up to a project, you can make a ER-32 collet holder.  Old Doubleboost shows you how:

https://www.youtube.com/watch?v=8SV7lDiSXto

ER-32 Advantages:

You can use all your spindle hole as you don't back tighten these collets (3/4" max size on ER-32)
Because of ER spring-design you don't need so many collet increments for the size range

ER-32 Disadvantages:

No commercial lathe collet holder (like Doubleboost's) design available
You need to be able to cut metric threads for a homebuilt holder
No hex or square ER collets.  Also ER collets are not the greatest for very short parts

5C Collet Chuck Advantages

You can use all your spindle hole and then some with the chuck (front tighten, 1 1/8 collets).
5C collets are a industry standard.  Hex, square, etc.  Relatively inexpensive.
Flat-back collet chuck should be an easy mount, just need to machine a back plate

5C Collet Chuck Disadvantages

Spotty QC and run-out reports on "cheap" import chucks, although DIY backplate does give you the best chance.
Good collet chucks are expensive.
It's best to have a 35 piece collet set (1/32) because these type of collets don't close very far.

The trouble with 3C is that your lathe already has a small spindle hole and adding a collet closer doesn't help matters.  

When I bought my lathe it came with a pretty complete set of 6K collets: all the 16th sizes with some spares, the bigger square and hex collets and some random oddball sizes.  It's a blessing and a curse.  A blessing in that I didn't have to buy all this as the 6K stuff, even used, is quite expensive.  A curse in that it's a dead-end street: the 6K collet is only used in the SB 10K lathe and I hate to spend any more money on this system.

If I was starting fresh, I would probably go the 5C collet chuck route.  You can actually hold some decent size rounds, up to the size of the spindle hole, along with hexes and squares.  Also any investment made in collets can be carried over to a bigger lathe if an upgrade happens down the road.


----------



## martik777 (Dec 19, 2014)

You can cut the 1.5mm threads for a homemade ER chuck by substituting the 20t stud gear with a 26t and set your QCGB to B4, or, make your own nut with imperial threads.  Another option is to use a MT3 collet chuck but no thru hole capability.


----------



## ashur (Dec 19, 2014)

DoogieB said:


> If you feel up to a project, you can make a ER-32 collet holder.  Old Doubleboost shows you how:
> 
> ER-32 Disadvantages:
> 
> ...


----------



## BillWood (Dec 19, 2014)

*Re: Collet ? Metric Thread ?*



DoogieB said:


> If you feel up to a project, you can make a ER-32 collet holder.  Old Doubleboost shows you how:
> 
> 
> You need to be able to cut metric threads for a homebuilt holder
> .



Am a bit puzzled - I believe you, but simply dont understand why a metric thread is required - what is it about an ER32 collet system that makes a metric thread compulsory ?

Bill


----------



## DoogieB (Dec 19, 2014)

*Re: Collet ? Metric Thread ?*



BillWood said:


> Am a bit puzzled - I believe you, but simply dont understand why a metric thread is required - what is it about an ER32 collet system that makes a metric thread compulsory ?
> 
> Bill



If you want to use a store-bought ER32 nut, you need metric threads on the collet holder.  Obviously you can make you own nut with whatever threads you want.  It's not a trivial job with the internal taper, but certainly not impossible.



			
				ashur said:
			
		

> Actually, there are a number of commercial options for “buying” a ready-made ER32 chuck for a 9x20?
> I bought a 1-1/2”-8 3 hole (to fit mini-lathe chucks) chuck plate and  then a “mini-lathe” ER32 3 hole chuck (to fit mini-lathe chucks).
> I bought one on eBay and one at Little Machine Shop (I don’t remember witch from where).
> This is my favorite “precision” chuck for my 9x20 lathe.  I didn’t have  to make anything & it’s my most accurate small chuck.



Yup, you are correct.  At first I thought you meant a MT3->ER32 collet chuck and obviously they suck because of the draw bar.  A 3/4" spindle bore is small, but having ZERO is even worse.   But you are correct, LMS has a ER32 chuck, part number 4231.  Turn down a chuck backplate. attach and it should be good to go.

Tallgrass Tools also has a ER32 collet holder, in kit and complete form, which looks very similar to the one in the Doubleboost video.

For 5C, you can get the MLA-21 Loop Collet Chuck kit.  A web search will provide more information; it's a different mechanism than the imported 5C collet chucks.

Sometimes turning adapters and chuck backplates on the same lathe that you will use the tooling is well worth the effort:  I removed .0025 of run out on my 3 jaw chuck with a new backplate.  Well worth it!


----------



## Halligan142 (Dec 19, 2014)

bisley45 said:


> If you had no collets and were going to purchase a set for your 9" south bend what would you get c3 or something else?




The 3c collets only go to 1/2" which is the biggest drawback, but that's what the lathe was designed to take.  In addition to the collets you'll also need a draw bar, thread protector/collet closer remover nut, and the spindle adapter from 3mt to 3c.  All of which can be a bit pricey.  The biggest advantage of collets is doing small work, repetitive work, work that would require you to remove from the machine a lot, or gripping tubes or threads as it won't damage them.  While they are nice to have, they are by no means a necessity.  Not trying to get off topic and I don't know what you have for your lathe, but if you don't have the basics yet,  A good 3 jaw, a 4 jaw, and a steady (almost a requirement on these lathes due to the small spindle hole) your money may be better invested in those first in my opinion.


----------



## Mark_f (Dec 19, 2014)

bisley45 said:


> If you had no collets and were going to purchase a set for your 9" south bend what would you get c3 or something else?



South Bend used 3C collets on the 9 inch lathe because of the small spindle bore. You can get a set of ten 3C collets on eBay for $55. You can make the spindle adapter. There is a print in the drawing forum I believe. You can also easily make the draw bar. The 3C collets only go to 1/2 inch, so if you want bigger , go a different route. You can buy a 5C chuck , but it sticks way out and takes a lot of the bed space. You can go as suggested earlier with an ER collet setup and it may take less space ,but will stick out some. So basically, your decision will be based on how big a work diameter you want and how much space you use. I have been happy with the 3C setup. Anything over 1/2" , I use the 3 or 4 jaw chuck. Good luck on whatever choice you make. They are all good ones.

Mark Frazier


----------



## martik777 (Dec 19, 2014)

The internal threading and taper for the collet nut are relatively straightforward, it's the internal eccentric that's the tricky part. I omitted it from mine and it works fine.


----------



## ashur (Dec 20, 2014)

My ER32 chuck "sticks out" less than anything I use (except a faceplate) and collets are available over an inch (22mm+).    .....Actually, I just measured and the ER32 chuck w/plate, when tightened, sticks out .25" LESS than the cheap 4-jaw that comes with the lathe.

As you can tell, this has become my favorite small round holding method!  I'm tempted to try to adapt an ER40 set-up.  I like these collets.  I need to stock less of them, they hold very well, and so far have been plenty accurate, especially for small parts!

------------------------



mark_f said:


> South Bend used 3C collets on the 9 inch lathe because of the small spindle bore. You can get a set of ten 3C collets on eBay for $55. You can make the spindle adapter. There is a print in the drawing forum I believe. You can also easily make the draw bar. The 3C collets only go to 1/2 inch, so if you want bigger , go a different route. You can buy a 5C chuck , but it sticks way out and takes a lot of the bed space. You can go as suggested earlier with an ER collet setup and it may take less space ,but will stick out some. So basically, your decision will be based on how big a work diameter you want and how much space you use. I have been happy with the 3C setup. Anything over 1/2" , I use the 3 or 4 jaw chuck. Good luck on whatever choice you make. They are all good ones.
> 
> Mark Frazier


----------

