Fitting Metric Chuck and Fitting to Flexispeed

[James AParticipant @jamesalford67616]

It is nigh on impossible to find chucks and other fittings with a 1/2" thread to fit the Flexispeed, but there is a plethora of equipment threaded 14mm. I have been considering turning up a spigot, internally threaded 1/2" and externally threaded 14mm to screw onto the spindle. This would allow me to fit new chucks, faceplates and, possibly, collets.

I was wondering, though, whether the overhang which this would introduce would be a problem, leading to avoidable flex and inaccuracies. Any thoughts?

Regards,

James.

[James AParticipant @jamesalford67616]

[David Clark 13Participant @davidclark13]

You could make a new mandrel with the correct thread. The surplus original threaded items would find a home on Ebay.

[Michael GilliganParticipant @michaelgilligan61133]

James,

I think the popular 14mm fit is now 1mm pitch … so, if you were prepared to skim the crests off the 1/2" thread, it may be just possible to make a tubular sleeve, internally threaded [somewhat less than] 1/2" and externally threaded 14mm.

It would be very thin, and would need to be made with great care and good material !

Then; David says, you could probably sell any original items … I suppose it depends whether you want to preserve the originality of your Flexispeed, or modify it.

MichaelG.

[James AParticipant @jamesalford67616]

Thank you for the replies. I do not yet feel confident enough to try making a new spindle, primarily due to the the Morse taper for the centre. This is the sort of thig which I had in mind.

:

Regards,

James.

Edited By James Alford on 03/10/2015 10:25:22

[Michael GilliganParticipant @michaelgilligan61133]

Posted by James Alford on 03/10/2015 10:24:59:

Thank you for the replies. I do not yet feel confident enough to try making a new spindle, primarily due to the the Morse taper for the centre. This is the sort of thig which I had in mind.

:

Regards,

James.

.

James,

That's why I suggested modifying the nose thread instead of making a new spindle.

Personally; I would be nervous of mounting a chuck on an extended adapter.

MichaelG.

[mark smith 20Participant @marksmith20]

Does it have a number 0 morse taper? If so why dont you just use one of those o morse taper adapters with a 14mm thread on the end??? Sorry if it doesnt have the O taper as i thought they were similar to Perris lathes. I dont know how secure it would be though without a draw bar like on Pultra lathes.

Such as thishttp://www.rdgtools.co.uk/acatalog/14mm-x-1-Straight-Shank-Threaded-Arbour-1-2–Shank-66346444.html

Edited By mark smith 20 on 03/10/2015 10:47:42

[James AParticipant @jamesalford67616]

Mark,

You are correct in that it has a 0 Morse taper, but it is a shortened one, not a full length taper. I have looked around a fair bit, and read threads by other people, and it seems pretty much impossible to locate a taper that will fit without a substantial overhang.

[Gordon WParticipant @gordonw]

I am not familiar with this machine, but if it were mine I would turn the existing thread clean off and to a decent depth. Make a sleeve , bore to suit the new spindle diameter with O/D 15mm. Fit to spindle with araldite, then skim od and shoulder then screw cut. I don't know if this is possible on your machine.

[mark smith 20Participant @marksmith20]

Does short taper mean that it only fit the narrow end with the rest sticking out? If so could you not mouunt it between centres and indicate the taper with a dial on the compound slide and reduce the taper until it will fit with minimal overhang? Im only a learner with metal machining so if this is rubbish please say so.

It should be easy enough to make a chuck back plate using the existing nose thread ,but that is only of use to one chuck.

Edited By mark smith 20 on 03/10/2015 11:50:34

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Gordon W on 03/10/2015 11:38:21:

I am not familiar with this machine, but if it were mine I would turn the existing thread clean off and to a decent depth. Make a sleeve , bore to suit the new spindle diameter with O/D 15mm. Fit to spindle with araldite, then skim od and shoulder then screw cut. I don't know if this is possible on your machine.

.

Gordon,

I broad terms, I am inclined to agree … but I can't see any reason to turn the existing thread "clean off" … Keeping the roots of the threads would do no harm, and would give somewhere for the resin to lie. [Personally I would use Loctite 638 in preference to Araldite, but that's just a matter of familiarity] {other readers please note; I don't want to re-open the 'press-fit' vs sliding-fit debate, it's just my preference for real-world jobs}

However: The reason I suggested that James might use truncated threads is that making the adapter screw-on would leave him the easy option to make another if screwcutting the first goes wrong.

MichaelG.

[Roderick JenkinsParticipant @roderickjenkins93242]

Gordon has, I think, the best solution. However, bearing in mind that James' only lathe is his Flexispeed, I would make the sleeve first and then turn the stub of the spindle to fit. It is usually easier anyway to turn a shaft to fit a hole rather than vice versa. Loctite retainer will hold fast as will Araldite, providing it is the slow setting sort.

This wasn't my solution, only because I already had a 4 jaw chuck that fitted the 1/2" spindle nose. A 14 x 1 spindle nose will be much more versatile. Making a whole new spindle wouldn't be difficult either. A length of 1/2" ground silver steel with a lump glued or silver soldered to the end would do admirably but one would have to bore and ream the 0MT.

Rod

[James AParticipant @jamesalford67616]

Thank you for all of your suggestions, which have given me plenty to think about. It seems that no one thinks that using a screw-on adaptor is a sound idea due to the overhang, which was my initial concern.

Rod has previously, kindly, offered to fit a threaded insert to a three jaw chuck for me, which is tempting. However, using Gordon's idea, I would have the opportunity to fit a wide range of chucks and accessories, which was my reason for thinking about the adaptor.

I cannot do screw cutting on my lathe, but can buy a suitable die. If I hold this in a tailsotck die-holder, will it be suitable?

Regards,

James.

l

[Ian S CParticipant @iansc]

I think I would bore out the 14 mm thread in the chuck to something larger, cut a thread in the hole(can be quite fine), then make a short sleeve, with a 1/2" thread in the bore, and a thread to match the new thread in the chuck. It might be best to fit the sleeve in the chuck first, then bore it and cut the internal thread, you would of course need another lathe to do this.

Ian S C

[LambtonParticipant @lambton]

The conventional way would be to make a chuck back plate with a 1/2" thread and register to suit the existing lathe spindle, then machine the front face to suit a standard chuck of suitable diameter. Arc sell a range of suitable small diameter back-plate fitting chucks at very reasonable prices.

When I first acquired a Drummond lathe many years ago this is how I fitted both 3 jaw and 4 jaw chucks.

I think this will give a more satisfactory result than some of the more ingenious methods suggested.

[James AParticipant @jamesalford67616]

Thank you for all of these suggestions, each of which clearly has its merits.

Realistically, if I rethread the spindle, assuggested by Gordon, will a 14mm die held in tailstock die holder be accurated enough? I do not have screw cutting facilities.

Regards,

James.

[Michael GilliganParticipant @michaelgilligan61133]

Posted by James Alford on 04/10/2015 19:32:16:

Realistically, if I rethread the spindle, assuggested by Gordon, will a 14mm die held in tailstock die holder be accurated enough? I do not have screw cutting facilities.

.

In my opinion: NO

MichaelG.

[Roderick JenkinsParticipant @roderickjenkins93242]

Posted by Michael Gilligan on 04/10/2015 19:35:59:

Posted by James Alford on 04/10/2015 19:32:16:

Realistically, if I rethread the spindle, assuggested by Gordon, will a 14mm die held in tailstock die holder be accurated enough? I do not have screw cutting facilities.

.

In my opinion: NO

Michael,

With a good fitting register I think a die cut thread adjusted to give, say, 65% engagement (and therefore a bit of slack) would be OK.

Lambton,

In an ideal world I would completely agree with you. The problem is finding a chuck that is in scale with the rest of the lathe. The only chuck in ARC's selection that is really suitable is the 60mm diameter one and this is over £100. Even this is a substantial (and I'm sure very accurate) chuck which, together with a backplate, probably puts rather too much overhang on the somewhat slender spindle.

Regards to both,

Rod

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Roderick Jenkins on 04/10/2015 20:49:31:

Michael,

With a good fitting register I think a die cut thread adjusted to give, say, 65% engagement (and therefore a bit of slack) would be OK.

.

Rod,

You may well be correct … I merely expressed my opinion.

My caution being driven by the fact that I don't know the 'register' detail of the readily available 14mm chuck mountings.

MichaelG.

[Another JohnSParticipant @anotherjohns]

Posted by James Alford on 03/10/2015 09:26:00:

It is nigh on impossible to find chucks and other fittings with a 1/2" thread to fit the Flexispeed,

What's the thread pitch? Sherline make chucks with a 1/2-20 spindle thread. They are good chucks – I have one of them, and would not hesitiate to get another one – they make a bit of a variety. Made in USA, if that matters.

[James AParticipant @jamesalford67616]

Posted by John Alexander Stewart on 04/10/2015 21:17:02:

What's the thread pitch? Sherline make chucks with a 1/2-20 spindle thread.

I believe that it is a 1/2" by 16 BSF thread.

[Roderick JenkinsParticipant @roderickjenkins93242]

Posted by Michael Gilligan on 04/10/2015 20:58:35:

Posted by Roderick Jenkins on 04/10/2015 20:49:31:

Michael,

With a good fitting register I think a die cut thread adjusted to give, say, 65% engagement (and therefore a bit of slack) would be OK.

.

Rod,

You may well be correct … I merely expressed my opinion.

My caution being driven by the fact that I don't know the 'register' detail of the readily available 14mm chuck mountings.

MichaelG.

Ooops! That was clumsy of me. By responding to your reply rather than James original request I implied a rebuke I hadn't intended.

Sorry,

Rod

[Michael GilliganParticipant @michaelgilligan61133]

Rod,

Absolutely no problem! … we're all on the same side [and, as I said, you may well be correct].

Thinking a little further: With no screwcutting facility … perhaps it would be sensible for James to 'make from' a commercially produced component [thus reducing the task to boring through, and cutting to length]

MichaelG.

Edited By Michael Gilligan on 05/10/2015 10:17:57

[James AParticipant @jamesalford67616]

Thank you for all of the suggestions. The one which I originally favoured was turning off the existing thread, fixing on a sleeve and threading it to fit the new chuck. However, having looked carefully at the spindle, the wall between the inside taper hole and the outside, once the thread has been removed, will be very thin, especially near the end. This rather puts me off the idea.

I have decided to buy a chuck anyway and just have a good look at the fitting. The pictures of it give the impression that it has a very deep, unthreaded 15mm register. If that is the case, I may be able to make a spigot, but use the depth of the register to reduce the increased overhang introduced by the spigot.

If, on the other hand, it does cause a large overhang, then I shall have to think again. Mind you, seeing this set up, I wonder……..

Regards,

James.

[JasonBModerator @jasonb]

Looking at my two Emco chucks with teh M14x1 thread it would be possible to machine say 2-3mm off the boss that sticks out teh back and open the threaded section out to 16-18mm.

You could then take a piece of 30mm steel, bore and tap to suit your existing spindle. Then screw that onto the spindle and reduce most of its length to a good fit in your modified chuck but leaving a 3mm flange at the head end, this would in effect become a backplate.

Now just drill for three M3 fixings and tap the chuck to match and you have a chuck with minimal overhang that will screw onto your existing spindle.

The register on an Enco U3 spindle is 14mm and the chuck plain hole 14.1mm

 

 

Edited By JasonB on 06/10/2015 08:13:12

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