Holding short lengths

[Raymond AndersonParticipant @raymondanderson34407]

Just received an e-mail from ETG Workholding [they must be agents in uk for Hardinge ] They can supply a 25 c chuck in D1-8 camlok fitting. They are making up a quote for the following, 1 set 25c collets from 30mm to 65mm [they actually start at 15mm but I have the ER40 on the GH 750 so will start from 30mm] 1 chuck and the prices of individual "emergency " collets. I will just make sure that I am sitting down when I open the quote .

cheers

[SteveIParticipant @stevei]

Raymond,

I think last year Hardinge outsourced some of the UK operation as the shophardinge UK website suddenly turned in to ETG Workholding. The prices went up as well, and the UK shop was already more expensive than the USA shop.

I've seen that amazon.com (.com not .co.uk) carry most of the Hardinge collets and are the same price as the USA shophardinge.com prices.

You have bad timing on this with the recent loss of value of the pound to the US$.

Steve

[Raymond AndersonParticipant @raymondanderson34407]

Hi SteveI , Thats typical… the rear end falls off the £ against the $ when I wanted it stronger . Still I will make sure I have a strong seat and the oxygen mask at the ready when I receive the quote. Once I am up and running I will stick some pics in an album.

cheers

Ps will go have a look at the Amazon site.

Edited By Raymond Anderson on 28/09/2016 15:20:52

[Howard LewisParticipant @howardlewis46836]

In an attempt to extend this thread to five pages, has anyone ever mentioned Bell Chucks?

For those who are not familiar, there are Internal and External versions, each one covering a range of sizes, in very small increments, capable of holding work as short as about 1/16" (1.5mm).

(Used a lot by the horological community, I believe) I obtained a set, (Not that I am capable of making a clock), but they come in useful for thinning washers. They would be ideal for the criminal offence of defacing coins of the Realm!

Mine, are Imperial, and will probably hold very short lengths, upto about 55mm dia .; depending on which of the multi stepped ones you use.

You just need to be careful not to run the tool into the very hard body.

Like so many tools, not used frequently, but invaluable for the odd unusual job, when it arises.

(I am sure that John S has many such bits and pieces for just such occasions in the course of his day job)

Howard

[JasonBModerator @jasonb]

The 5C step chucks that we have been talking about are basically bell chucks, if you look at that last video I posted the one shown closes like a bell chuck but teh larger ones have a tapered closer that applies the pressure on teh outer dia.

[Michael GilliganParticipant @michaelgilligan61133]

Posted by JasonB on 28/09/2016 15:30:07:

The 5C step chucks that we have been talking about are basically bell chucks, if you look at that last video I posted …

.

Jason,

Just for info. … the horological equivalent typically has multiple steps: **LINK**

http://levinlathe.com/StepCollets.htm

Obviously only suitable for very short workpieces.

There is also a 'ring holding' version, which is rather clever

http://www.nielsmachines.com/en/lorch-las-llk-lan-step-collets-set-and-ring-colle.html

MichaelG.

Edited By Michael Gilligan on 28/09/2016 15:53:25

[Neil WyattModerator @neilwyatt]

Posted by Michael Gilligan on 28/09/2016 15:46:36:

Posted by JasonB on 28/09/2016 15:30:07:

The 5C step chucks that we have been talking about are basically bell chucks, if you look at that last video I posted …

.

Jason,

Just for info. … the horological equivalent typically has multiple steps: **LINK**

http://levinlathe.com/StepCollets.htm

 

Edited By Michael Gilligan on 28/09/2016 15:53:25

You could get that effect using soft jaws…

Edited By Neil Wyatt on 28/09/2016 15:55:31

[JasonBModerator @jasonb]

Posted by Michael Gilligan on 28/09/2016 15:46:36:

Posted by JasonB on 28/09/2016 15:30:07:

The 5C step chucks that we have been talking about are basically bell chucks, if you look at that last video I posted …

.

Jason,

Just for info. … the horological equivalent typically has multiple steps: **LINK**

So do the 5C ones once they have been used a few times

Yes Neil, they are in effect soft jaws for a 5C chuck, in the larger diameters thay have the advantage over soft jaws of gripping the work all round, handy for holding thin hollow work which won't be distorted as it would with 3 soft jaws bearing against it.

Edited By JasonB on 28/09/2016 16:08:14

[Michael GilliganParticipant @michaelgilligan61133]

Posted by JasonB on 28/09/2016 16:05:26:

Posted by Michael Gilligan on 28/09/2016 15:46:36:

.Jason,

Just for info. … the horological equivalent typically has multiple steps: **LINK**

So do the 5C ones once they have been used a few times

.

MichaelG.

[JasonBModerator @jasonb]

Raymond, if you go with the 25C what method will you be using to accurately mount these short c40mm dia parts in the collet so they run true eg across the lathe axis and don't wobble? I'm assuming you wil want the same 0.01 accuracy or better as the collets concentricity.

J

[Raymond AndersonParticipant @raymondanderson34407]

Jason, I have asked ETG workholding to also give me the price of emergency collets It will be these that I will machine to suit any short part [s] . Going with the 25c gives me an increase in Ø before I need to use the soft jaws. I just don't like machining soft jaws on a 315mmØ chuck to hold a part that is maybe only 35mm or so in Ø.

The other lathe [the GH750 ] also has soft jaws and if the part happened to be of a bigger Ø than the 25c's can handle then I can use them. that chuck is only 150mm Ø. Going with the 25c's also gives me a lot of scope before I would have to change the GH 750 chuck as it usually has the ER 40 on it. I often used split bushes and again the 25c's give me more scope.

Looking at the 25c's also tells me I could easily knock up blanks for machining, as there is nothing too complex in them. [ certainly not for ones that are going to be machined anyway ] Still waiting to hear back with the quote That could be an ominous sign

cheers

[AjohnwParticipant @ajohnw51620]

The horological lot also use another style of collet. How to describe it. Basically the nose extends and is bored to the required size with a shoulder at the back of the bore. A sort of deeper version of the ones that Jason shows but not such a large diameter.They just go some way past the max bore of the standard collet.

If there are lots of these parts I'd be wondering about soft jaws. They can hold with a high degree of precision even without following these steps which are for holding a specific size.

The first thing to do is to machine a recess into the very back of the jaws. It doesn't need to be very long but does need to leave a definite shoulder. Then close down on a "washer" pulled back into the recess with a bit of bar or what ever and then machine the jaws to suit the work, That way a shoulder can be left in the jaws to press the work back onto when it's held.

If the work needs to pass completely through the jaws one more step is needed. There will be a slight lip left where the washer was so just lightly machine it out. When the jaws are initially machines it will only be a few thou plus the tool rad wide.

These can hold work as well as any collet. The only problem really is if the lathe turns much of a taper but even then people use them – within reason. It's not so important when thin work is pressed back onto a shoulder. The chuck also needs to be in reasonable condition.

There is also a style of chuck about where the actual jaws are bolted on and the lower part in contact with the scroll is just a carrier for them. I'd like one but cost for me is a problem. One of the most noticeable things about my Burnherd chucks against both polish and chinese is the fineness of the parts – even the thickness of the scrolls. I'd want something similar and they cost way more than the usual stuff.

It wouldn't surprise me if Rotagrip could provide suitable items.

John

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[JasonBModerator @jasonb]

Posted by Raymond Anderson on 29/09/2016 09:24:21:

Jason, I have asked ETG workholding to also give me the price of emergency collets It will be these that I will machine to suit any short part [s] . Going with the 25c gives me an increase in Ø before I need to use the soft jaws. I just don't like machining soft jaws on a 315mmØ chuck to hold a part that is maybe only 35mm or so in Ø.

cheers

So if you are going to machine them all for short length holding and you say you are not using them for long lengths why go to the expense of a large 25C chuck and large expensive emergency collets?

You could quite happily go for a 5C chuck with suitable nose to close the 2" dia 5C emergency step collets and save a packet. You could with the money saved get a couple more closing rings and then have a few 3" & 4" step chucks that could also be machined as needed, ideal for rings that even soft jaws would dstort at those sort of diameters.

J

[Raymond AndersonParticipant @raymondanderson34407]

I hear what you are saying Jason, I have decided to equip the DSG with collets partly because a machine like that warrants it. rather than only the 3 and 4 jaw chucks. I will actually use the thrugh bore ones for longer lengths as that size collets makes use of the spindle bore. So once I have then then both lathes will have collets to suit their size The Gh750 could accept slightly larger collets (spindle bore is 38 than the er 40 but im happy with that
size on it.
Had I gone the Smaller route then I would most likely in the future say ” I wish I had gone bigger ” so that scenario wont apply.
cheers.
Still no quote arrived yet.

[Raymond AndersonParticipant @raymondanderson34407]

Still no quote through !! How long do people need? certainly not this length of time surely. If there is no figure through by today they can "shove it ", and I will look at other sources.

 

Ps,  ETG are maybe reluctant to send me the figures, in case I have a "turn "

Edited By Raymond Anderson on 05/10/2016 08:18:00

[JasonBModerator @jasonb]

Probably not got a calculator with enough digits on it to fit the total in

[Raymond AndersonParticipant @raymondanderson34407]

Jason, It will be interesting to compare my "rough " tally up to the actual figure. I hope me rough was was not to rough bearing in mind me tally up was from the american site and did not include the chuck !

Oxygen mask is all ready.

[AjohnwParticipant @ajohnw51620]

Not sure how big you want to go but

**LINK**

That needs a draw bar I think but it does offer rather good precision.

The type of chuck I mentioned is this one. The jaws fit on a sort of cross tenon – me thinks but best check,

**LINK**

I wish I could justify a smaller one. The soft jaws can be trimmed up for each job.

John

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[John Stevenson 1Participant @johnstevenson1]

So looks like my soft jaw alternative that can hold millions of sizes up the 6″ diameter, cost about thirty quid and an afternoons work is looking promising given that with this thread and the ER thread, by the time you have reckoned everyone’s time in anything else is into the tens of thousands of pounds in wasted time.

I think “my accused and alleged sock puppet” Alan Frost summed it up quite well.
If you are into model engineering you won’t have the problem. If you are into production engineering then you won’t be for long

[Raymond AndersonParticipant @raymondanderson34407]

For ***** sake JS give it a rest , you're beginning to sound like a "parrot ". now please take note, I like soft jaws, no, I LOVE soft jaws, but It's going to be collets for the DSG. [ as well as the soft jaws ] Maybe I should put an advert in the Guardian in ten inch deep banner headlines "Raymond really does like soft jaws " but he's going for collets..

[AjohnwParticipant @ajohnw51620]

I wasn'r aware that a single collet chuck could hold both multibore and spring collets Raymond.

Interesting idea as the multibore bar chucks can be useful.

My recollection of the DSG is a massive set plus a draw bar. I wonder what happened to the lathes sometimes. Circa 10 in one section and all fully equipped. The only real tat was a Chipmaster. Very nice clean pristine condition but bearing wear beginning to show due to hours of running at 3,000rpm. Probably about 3months per year but not sure how old it was. Not very I suspect.

John

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[Raymond AndersonParticipant @raymondanderson34407]

Ajohnw, They are 25c collets not multibore. up to 65 mmmØ. the spindle bore of the DSG can take a 3" / 75mm bar.

[AjohnwParticipant @ajohnw51620]

It states clearly that it takes both Raymond

**LINK**

Crawford din multi and spring collets.

Out of price range so academic – but I could possibly stretch to a 125mm back plate version of the 3 jaw.

John

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[Raymond AndersonParticipant @raymondanderson34407]

Hi Ajohnw, The ones I am waiting on a price for are Hardinge 25c I think the chuck for the 25c's will be different from the one you linked to. { although i'm just guessing as I have not seen the chuck yet } only the collets.

[Raymond AndersonParticipant @raymondanderson34407]

Ajohnw, Just had a closer look at the chuck you linked to and that is for multi bore and 173E collets. The 25c's are larger and a different style, really just a scaled up 5c. and I have a feeling that the price for the chuck will be a lot more than the one you linked to…. but all will be known when [ if ever ] I get the quote.

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