Super 7 - Best way to use ER25 Collets

If I was starting from scratch, not having any of the ER, I would also go for the larger sizes such as ER32 or ER40 with plain shanks to fit in an existing 4 jaw independent chuck. The shanks can be cut shorter with a hacksaw if they project too far out of the chuck. Using a 4 jaw chuck allows for adjusting for minimum run out every time.

Go for a 2 piece ER collet chuck screwed to the spindle nose. The reason for 2 part is you can turn the register yourself (as you would with a scroll chuck backplate) to ensure concentricity. Myford do them if you cannot find anyone else.

regards Martin

Edited By Martin Kyte on 03/06/2019 14:01:40

An advantage of a MT collet chuck that plugs straight into the spindle is it has very little overhang, which is good for rigidity and minimises any trace of headstock misalignment.

Next best in terms of reducing overhang is a backplate mounted collet chuck, perhaps another 30mm out.

Worst overhang would be a plain collet chuck in a 4-jaw, the depth of the 4-jaw chuck plus another 30mm from the jaws. (Slightly less satisfactory than using a plain 4-jaw rather than a collet.)

But perhaps minimising overhang is a booby trap. Could a Myford owner comment on how close a cutting tool can be brought to the headstock without cranking the tool-post to the extreme left or uncomfortably extending the tool? On my Chinese lathe the generous saddle stops me getting as close to the headstock as I would like. Is the Myford's gap-bed similarly limiting?

It would a shame to fit an MT collet chuck only to find tools have trouble reaching it due to the lathe's geometry.

Dave

Edited By SillyOldDuffer on 03/06/2019 14:20:53

The Myford was designed to use Myford Collets which are 2MT direct into the spindle and are retained/ tightened with a closing ring which screws onto the nose thread. This gives the absolute minimum of overhang.The lathe was designed to be capable of turning right up to the nose. The only limitation is when the lathe is equiped with a gearbox the leadscew guard can foul the gearbox when working right up to the nose when the topslide is fully retracted. With a screw on ER chuck there is a greater overhang and this does not occur. Even when working right to the spindle nose I have never had to extent the topslide excessively. Myford collects are no longer avalable new but can be found second hand. Myford collets should only be used with dead to size material, either initially pre turned to size or precision ground stock.

I hope that answers the question.

regards Martin

Edited By Martin Kyte on 03/06/2019 14:43:47

Thanks Martin, Myford score again!

Alright then.

A lot of things to digest and reply to.

1. I'm going for ER25 and not any bigger because I really don't need it. The ER11 collets sound like a great future project once I'm settled in and got to terms with the lathe, maybe acquired more machinery.

2. No drilling! I haven't got a workshop at home, and I'm about to go on holiday for 3 months. I have a lathe and that is it. So a good idea to make my own backplates and drill them but sadly I can't. Thank you though.

3. I can't afford MT2 collets that go straight into the spindle. As I said, I'm a student and although I can afford a Super 7, this is just about all I can afford. So the ER collets is the cheaper alternative.

So, I'm left with turning the registry on a two part solution from RDG tools to accept the collets, or as John said RCM tools have the old style holder (RCM Tools - ER32 Holder), which looks to be cheaper and easier for me.

Really the question is, is there a difference between these two setups?

Many thanks to all that replied,

Alex

Ah ha, I suspect you've not laid your sticky paws on a copy of Sparey's "The Amateurs Lathe" yet. Drilling on a lathes is a common operation. Holes are usually drilled centrally, but by offsetting the job on a faceplate or 4-jaw chuck, provided there's space you can drill holes anywhere with great accuracy - far better than a pillar drill.

The method's less commonly mentioned today because setting the lathe up takes time and many people have a convenient bench drill or milling machine ready for action. When Sparey wrote lots of people only had a lathe and it was used for milling and drilling as well as turning, boring and threading. Sparey covers it all and he's a cracking good read too!

Dave

Backing up SOD’s post, Edgar T Westbury supplied a large amount of plans for home workshop projects. Virtually (?) all used only the lathe as the only powered machine, for making the very practical tools, models,etc.

Hemingway (and others) can supply a range of those projects, and write-ups are to be found in past ME mags. Of course many use other kit than the lathe, but most things can be made with just the lathe and a few hand tools..

A cheap milling attachment can be added to avoid a lot of the time-consuming positioning for drilling etc. I expect the modellers in the middle of the last century became very adept at sorting out how to do a lot with just their lathe at their disposal!

I got my ER collets from here : **LINK**. Might be worth having a look, especially if you need other engineering components.

Harry,

In MEW March 2007 issue 123 Harold Hall described how to make an ER32 collet chuck to screw onto the Myford nose. I made a similar one to fit the Atlas nose and it was an easy task using the lathe only.

The advantages are that the taper can be turned with the collet holder screwed into place thus ensuring accuracy and, if you are short of money, it's the cheapest way to go. It would be easy to make one for ER25 collets but I would recommend ER32 for the extra capacity.

Russell

Whilst on the subject of collets; I have a 4MT/ER25 collet chuck adaptor that fits into the spindle of my WM250V-F plus a set of ER25 collets, as this set only goes up to 16mm I would like the ability to fit a larger collet that would take 20mm, would a ER32 20mm collet fit, I believe the tapers are the same, other than buying another MT adaptor has anyone fitted a ER32 collet to a ER25 collet chuck ?

George.

An ER32 collet will not fit an ER25 collet chuck and vise versa.

Alex, if you get a MT2 holder, it will require a 10mm drawbar. The cheapest way to make one is by getting a length of 10mm studding and a couple of nuts. You will still have to turn up and drill something to fit in the left hand end of the lathe spindle to seat the drawbar.