# 5c or ER Collet Chuck



## kendo (Sep 19, 2010)

Hi Folks
     I hope to be taking delivery of my new lathe some time in the next few
     days, just waiting on a delivery date.
     I would also like to purchase a collet chuck for it. But I'm not sure which
     route to take, 5c chuck or ER chuck. 
     Or are they both the same as far as accuracy and holding goes.Or is 
     it just a case of the users personal preference.
     Is one better than the other ? if so which one ?
     Any advise would be gratefully received, Thankyou in advance.

                    Ken


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## DICKEYBIRD (Sep 19, 2010)

I have ER32 chucks on my lathe and mill and really like them. ER's have a wider gripping range, ie: they're more tolerant of stock size variations. 5C collets need the stock size to be very close for proper grip.

ER's don't work with short pieces as well as 5C's. Not a big deal to make a plug to go in the back of the collet when necessary though.

I bought my ER-16 and ER-32 collet sets from CTC in Hong Kong and am very happy with the quality and especially the price. I'm on a very tight budget so the higher priced sets weren't an option.


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## peatoluser (Sep 19, 2010)

hi kendo
the difference betwween ER & 5C collets is that ER collets are slotted from both ends and therefor will close at the back as well as the front. this gives them a greater gripping range of diameters than a 5C collet which are split from the front only, typically a range of 1mm. Also, because 5C collets only have a narrow range they should , strictly speaking, be used only with precision ground bar - ordinary BMS (CRS) can be upto 5 thou down on dia. and this would mean that the collet is gripping too much at the front than the back. the advantage of 5C's is that you can get them in square or hex, at a price no doubt, and that some indexes or rotary tables take them. also they have a single body dia. and a maximum holding size of 30mm round/ 18mm sq. whereas an ER32 chuck has a max of 20mm round only although there are larger ER sizes.
for general work holding in a lathe i would prefere ER to 5C for thier greater gripping range per collet and buy a self centreing 4 jaw chuck . that's if i had the money for either! i'm quite envious of your predicament!
yours peter


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## John S (Sep 19, 2010)

Go for ER's
More universal in sizes and use. They are both work holding and tool holding.
Anybody every seen a milling machine with 5C's ?

John S.


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## bob ward (Sep 19, 2010)

I'm relatively new to machining and was faced with the same question a couple of years ago. I decided that I only wanted to have the one collet system across the 2 machines, ie mill and lathe, and went for ER32 collets.


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## shred (Sep 19, 2010)

Unless you need to hold hex or square stock in collets, I'd go ER too. But, if you are into acquiring old surplus machines and tooling, sooner or later you may end up with 5C as well. At least in the US it's difficult to avoid 5C tooling (indexers, collet blocks, dividing heads, collet attachments, etc) in anything but the smallest sizes. There's a neat adapter available in the UK (didn't John S come up with it?) that I've been meaning to get for a while now, as I've been muddling along with sticking a straight-shank ER holder in a 5C collet.


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## rklopp (Sep 20, 2010)

If you can afford it, go for conventional split collets instead of ERs for lathe work. I find using ER collets on a lathe to be a royal PITA compared to conventional split collets (e.g., 5C). ERs are slow and clumsy to operate, they lack feel, you can't grab short stuff, you can't get the tool close enough to the collet face (it's recessed into the nut a little), and they can mark finished workpieces. I have an ER16 chuck with a straight shank that I grab in a 5C, for those times when I don't have the right size 5C, such as when working on some sizes of machine screws. I use it as little as possible. 

I have ER holders for my mills, and I like them for that application.


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## don-tucker (Sep 20, 2010)

I'll go along with that rklopp,I use er collets on the lathe but they have there limitations on the mill ,great.
Don


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## bob ward (Sep 20, 2010)

shred  said:
			
		

> ........ that I've been meaning to get for a while now, as I've been muddling along with sticking a straight-shank ER holder in a 5C collet.



Sharing ideas here, this is something I originally made just as a practice piece, an ER32 collet holder with 50mm shank and a 21mm bore. It has turned out to be very useful for turning eccentrics in the 4 jaw.


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## kendo (Sep 20, 2010)

Peter: thankyou for your reply , very informative, BTW my lathe arrives tomorrow
 can't wait ;D

 John: Thankyou also for your reply.

 Shred: I see your point, maybe some time in the future i may want to machine
 hex or square stock, and that a 5c collet would be very handy, but for now 
 i guess i will have to stick to a four ed jawed chuck. Thanks 

 Rklopp: Thankyou also for your reply , iwill take on board your view, cheers.

 Don-Tucker: Thankyou also for your reply.

 Bob Ward: Cheers Bob, what a great idea, i will have to store that one away
 for the future, thanks also for the picture.

              Thankyou Guys For your Responses  :bow: :bow: :bow:


                        Ken


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