ER Collet Drawbar

[PaulR]

I'd like to get a few collets for work and tool holding in my little lathe. The headstock has a MT3 taper and I plan on getting 3,4,5 and 6mm collets but it might be more economical to buy a set. It seems that ER16 is the type I need based on the headstock taper, something like this:

https://www.rdgtools.co.uk/product/3mt-er16-collet-chuck-with-1opc-collet-set-1-10mm-and-spanner-rdgtools/

Can anyone confirm I'm looking at the right thing? I take it some 12mm studding/nuts/washers would do for a drawbar? I cant thread anything above 10mm myself although I could fix a 12mm bolt to a length of steel rod...

[ShopShoe]

Paul,

What lathe do you have?

You can certainly make a drawbar to hold the collet chuck from a set like you show. I have done some myself, either from rod that I have threaded, or using threaded rod in a pinch.

Sets like you show would provide the sizes you need with some others for future uses.

Looking at information on the different ER collet ranges, you may have identified ER16 as what you need.

It is possible to make a collet chuck: There are others' projects which show what is involved. Unfortunately I can't easily find one to link to.... You do need to cut threads to make one.

There is another consideration for collet chucks and that is whether you want to be able to feed long stock through the headstock, if your lather allows it. I don't know whether you can find one for your lathe and for ER16.

ShopShoe

[PaulR]

Paul,

What lathe do you have?

You can certainly make a drawbar to hold the collet chuck from a set like you show. I have done some myself, either from rod that I have threaded, or using threaded rod in a pinch.

Sets like you show would provide the sizes you need with some others for future uses.

Looking at information on the different ER collet ranges, you may have identified ER16 as what you need.

It is possible to make a collet chuck: There are others' projects which show what is involved. Unfortunately I can't easily find one to link to.... You do need to cut threads to make one.

There is another consideration for collet chucks and that is whether you want to be able to feed long stock through the headstock, if your lather allows it. I don't know whether you can find one for your lathe and for ER16.

ShopShoe

Thank you. My lathe is a SEIG SC2, the baby of the range.

[Roger B]

Bolt on ER chucks exist in various shapes and sizes. I don't know if this will fit your chuck mounting. There were a few variations in register diameter and PCD on the smaller minilathes. As ShopShoe says this will allow you to pass longer pieces through the headstock

https://www.rcm-machines.com/en/rcm-production/chuck-er/1-er25-collet-chuck--80-mm/rcszf2580t

RCM offer other sizes as I expect do other suppliers.

[Krypto]

Giving up access to the spindle hole of your lathe is not a decision to be made lightly.  There are other ways to use collets for work holding on the lathe.

After buying a set of atrocious ER11 collets that ended-up in the garbage can, I now only buy collets that list a run-out specification.  They cost more, but not that much more.

[PaulR]

Bolt on ER chucks exist in various shapes and sizes...

Thanks Roger I'll think some more on the best way to go.

[PaulR]

Giving up access to the spindle hole of your lathe is not a decision to be made lightly.  There are other ways to use collets for work holding on the lathe.

Thanks for this. I was making the assumption that the tapered chuck was hollow until somewhere near the thread for the drawbar - is that not the case? If it's solid then it would be of limited use so maybe a bolt-on chuck would be the better option.

[Krypto]

You want to leave the spindle hole open the whole way as you can save a lot of bar stock.  According to the internet, your lathe has a 20mm spindle hole (3/4") so you should probably use ER32 collets.

https://doug.sdf.org/2021/08/06/another-er32-collet-chuck-for-the-south-bend-10k-lathe/

That's an article on how I mounted an ER32 collet chuck on my lathe, but it will do you little good as this mounting setup is completely different than your lathe.

Back in the day a 3C collet system was another choice for a lathe with a MT3 spindle grind, but that system seems to have really dropped off in collet availability.

[Spinner21]

3c collets are still available from ebay  and sellers like Rotagrip but they are rather pricey compared to ER collets.
I think I would stay with an ER 32 system as suggested earlier and using a mount like your standard 3 jaw chuck.
Andy

[Zephyrin]

you may use simply M3 collets in the headstock of your lathe, they are available cheaply from 2 to 20 mm, either as a set or individually, and are closed by a drawbar in your lathe, ie a simple piece of M12 threaded rod, a washer and a m12 nut.
they are good for tool holding and stock material at nominal size only, as they are too stiff for holding intermediate size.
the overhang is reduced to the minimum.

https://fr.aliexpress.com/item/1005009939561522.html?src=bing-language&exp_tag=pcgcp&albch=shopping&acnt=135095331&albcp=555772767&albag=1309519649356845&slnk=&trgt=pla-4585444533028494&plac=&crea=81845043295810&netw=o&device=c&mtctp=e&utm_source=Bing&utm_medium=shopping&utm_campaign=PA_Bing_FR_PLA_ALL_TROAS_PURCHASE_AESupply_%E5%A4%9A%E8%AF%AD%E8%A8%80_EN_26.4.15&utm_content=Ad+group+%231&utm_term=m3+taper+collets&msclkid=becdf8a88e4b15b625d59269f317371e&aff_fcid=ff1b55d6e50043e393b1c367ba810d06-1791065466062-09730-UneMJZVf&aff_fsk=UneMJZVf&aff_platform=aaf&sk=UneMJZVf&aff_trace_key=ff1b55d6e50043e393b1c367ba810d06-1791065466062-09730-UneMJZVf&terminal_id=3f5b00762cee4b669114a3e14b3f1473&afSmartRedirect=n&gatewayAdapt=glo2fra

[Charles Lamont]

I agree with going for ER32. In addition to leaving the spindle hole clear, a chuck mounted on the spindle nose will probably be a more rigid arrangement than using the taper. If you are going to MMEX have a look at what is available.

[PaulR]

Thank you all for the advice  It seems like ER32 with a chuck mounted on the spindle rather than a taper/drawbar is the way to go. I'll make a note of the necessary measurements and have a look at the show in a couple of weeks time.

[PaulR]

I found a suitable  ER32 spindle-mounted chuck online at a really good price, I'll pick up some collets and a spanner etc at the show hopefully.

[Sanjay F]

I found a suitable  ER32 spindle-mounted chuck online at a really good price, I'll pick up some collets and a spanner etc at the show hopefully.

My list of 'things to pick up' is getting longer; I hear there's no exhibtion discount or special discounts for MEM members .....now that would be good (for us anyway) 

[Jasonb]

You might get a bit off or at least a rounded figure ( hopefully downwards) if you use cash