Holding short lengths

[SteveIParticipant @stevei]

Ref soft jaws, point taken they are much more economical. Yet many model engineers buy collets and don't buy soft jaws. The OP wants a collet solution so I suggested one that was cheaper than the other options discussed. When it came to the large sizes an emergency collet or emergency step chuck is simply a variation of soft jaws.

 

Raymond, Hardinge make it. Hence it is expensive. You can see the whole solution on shophardinge.com. 

For me the only option has been the 2nd hand market. The closers are made from cast iron and could very well be home made most easily for the threaded nose variant. I estimate I've paid about 10% on average of new price for crawford or hardinge brand and then I have a few Chinese new items. It still adds up  and much much higher than soft jaws. 

 

Post edited due to being out of sync with prior responses.

Edited By SteveI on 26/09/2016 19:56:50

[JasonBModerator @jasonb]

Raymond, about page 8 & 9 in the hardinge catalogue, you need the ring to apply the pressure to teh outside of the large dia collets. The cheaper multi stepped collets you can buy don't close down so well using the standard 5Cs taper

But 5C won't hold long lengths above 1 1/8" ( or pass through above 7/8" or so) so you will still have to have a bigger collet system to cover you between 28 and 45mm which would up the costs and mean more chuck changing

 

Edited By JasonB on 26/09/2016 19:51:28

[AjohnwParticipant @ajohnw51620]

Posted by Michael Gilligan on 25/09/2016 19:52:43:

Posted by Ajohnw on 25/09/2016 19:28:28:

Posted by Gary Wooding on 25/09/2016 13:05:53:

Posted by Ajohnw on 25/09/2016 12:32:12:

 

I already explained why the wont do that in another thread. Long, no notice taken so I just sit here laughing saying up yours. I should have added a bit more though.

Can you supply a link please. I still don't understand. Does hardened steel compress to any noticeable extend when used as the springy jaws of a collet?

 

That's what I pointed out. You don't want to read who knows how many pages there are on the ER collet thread – so just believe me.

John

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.

The hardened steel doesn't need to compress noticeably … The ER collet is split at both ends; it's the shape that can 'compress noticeably', not the material.

MichaelG.

Not relevant Michael. The compression under discussion in this area is the actual compression of the metal that makes up the collet not the fact that it can collapse to accept different sizes.

It's not a hard point to grasp. Put something in one and clamp it in the chuck. The tapers match and the collet collapses until it grips what ever is in it. It will only go so far before the part needs to compress for the collet to close up more. The tapers still match so there is no reason why they should go bell mouthed or anything else. The only way they could do that is if the material that makes up the collet actually compresses significantly.

That just leaves alignment issues that I mentioned. So on that basis if 2 x dia is always griped everything will be ok. However 2 tapers being exactly the same is unlikely. That may be why some one came up with he idea that 2/3 of the length of the collet is fine. The difference in the tapers will translate into a taper in the bore so in real terms grip length apart from alignment doesn't matter.

My conclusion is that they need a longer grip length than typical spring collets because at some limit they will have a number of problems. This also holds with the general view of them. What finally put me off was using ER40 to grip small things. If I had ER on a lathe I would try using any size gripping a length of at least twice the diameter of the work and expect it to be ok. Certain factors such as lack of true roundness, number of parts in the collet that should be in contact with the work but wont be make me wonder so it wouldn't surprise me if the 2/3 collet length rule was about ok.

But as I mentioned no way would I just stick to one size of ER collet even on a miller. It just doesn't make any sense – to me.

I can't see that making slugs to put at the back will help really – will they be exactly the same size. In terms of people who buy the very accurate types unlikely really so no help or make things worse. It would make more sense to try 2 diameters and see what happens.

John

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Edited By Ajohnw on 26/09/2016 20:33:53

[SteveIParticipant @stevei]

Jason,

The round go up to 1 1/16" max size for pass through admittedly without the internal threads. With internal threads they max out at 63/64". For none pass through a little bit more, and then with the 2" step chucks up to 2" for short lengths. The regular depth 2" step collets are deep enough for the OP's specs. If I've read it correctly I don't think Raymond would need to change main chucks (but would need to change collets and collet closers) for his stated entire short part working range. As you correctly point out if he wants to pass through bar or longer parts in the diameters above approximately 1" then it is not the right choice for Raymond but if I understand his posts correctly he is clear he doesn't need to do that. So why pay more for a larger collet solution that meets the specification of the OP?

[JasonBModerator @jasonb]

Thanks Steve, could not remember the exact sizes off hand but know a few of my larger size ones won't pass stock through them though they are all internally threaded.

I thought Raymond was looking for a complete new system upto 40-45 and with the ability to take short lengths not just a system for short lengths only, Raymond can you con firm which you are after.

[Mark CParticipant @markc]

AJohnW,

As was pointed out before in this or the other Er thread, you really should read the post in order to comment constructively. When you state;

"It's not a hard point to grasp. Put something in one and clamp it in the chuck. The tapers match and the collet collapses until it grips what ever is in it. It will only go so far before the part needs to compress for the collet to close up more. The tapers still match so there is no reason why they should go bell mouthed or anything else. The only way they could do that is if the material that makes up the collet actually compresses significantly."

it is obvious that you have no grasp of the geometry involved. The conical form only mates in a coincident manner when the two cones are co-radial at a particular diameter. Think about a cork being forced into a bottle, the cork must compress as it is forced down the taper – this is much harder with metals (requires several tens of Kbar if I am not mistaken) which is why the collets are always split to allow them some space to deform due to elastic/spring behaviour of the collet design.

If you take a close look at Crawford multisize collets (there are lots of pictures on the web) you will see there is a tapered relief on the segments to allow the collet to transit from the open position = broad line contact in central section to the closed position = broad line contact at the edges of the collet external tapered flanks.

Mark

Edited By Mark C on 26/09/2016 21:00:48

[Michael GilliganParticipant @michaelgilligan61133]

John,

It's good to see you contributing again, instead of sitting smugly in your corner humming "up yours".

Frankly, however, I don't understand your post … I thought we were trying to clarify something for Gary.

MichaelG.

[Raymond AndersonParticipant @raymondanderson34407]

Hi Jason,Steve, yes they are for short parts only up to around 40/45 dia so dont need pass through. In fact they can all be emergency style ie, pilot bored only.
I am still at the checking out stage but would like to have a “definite” by next week. I am also still thinking about making my own and could either be from steel or 7075 as they are simple to make and accurate. If I do decide on a manufactured system I would prefer a known maker ie, Crawford, Hardinge, or such there are a few out there. I often will use the soft jaws on the Bison as I have made 4 sets and do use them for short parts of a large dia and I also use split bushes with a flange, but for anything around 40/45 and under I would prefer collets.
Cheers.

[Raymond AndersonParticipant @raymondanderson34407]

Jason, Just had a chance to look at the Hardinge Catalogue you linked to Page 8 / 9 The 5 C step chuck and closers appear to suit me needs although I cant see any mention of manual lathe spindle nose fittings. All appear to be the A series which I think is a CNC nose [although not fully sure on that ] I would require a D 1-8.

Looks promising if I can resolve the Spindle nose fitting. Will e-mail Hardinge and get their answer as regards the spindle nose.

cheers.

[JasonBModerator @jasonb]

I know they fit a Hardinge HLV nose which is 5C internal and tapered externally. You hould not have too much of a problem replicating this nose type with a D1-8 mounting if nothing is available off the shelf

[Raymond AndersonParticipant @raymondanderson34407]

Thanks Jason. I have e-mailed Hardinge and await their reply.re the nose fitting.

cheers

[alan frostParticipant @alanfrost17805]

Afraid I don't understand what all this c—p has been about,nor why we need another marathon series on short lengths.. For 99% of us who are happy just to get the job done the solution is pretty obvious ,ERs, and if some lucky model engineer has a machine that is powerful enough that these give problems then reduce the cut,or is this too easy ? Judging by the "Guhring " video any cut classed as just short of "Brutal" should not be a problem.

For the small number who are reading a model engineering site but are involved in production then reducing the cut may be less welcome and increase machining time and cost. However if they can't analyse their problem and come up with an alternative method of work/tool holding they should n't be in the business of producing metal parts,and probably won't be for long. So who has a problem ? No one, except production machinists who should know enough to solve their own problem . In other words no one has a problem. Model engineers can't produce the problem and those who can should know the answer.

i do find it instructive that Mr. Stevenson has typically ,IMO, offered to come up with, and will no doubt do so, a solution to the problem for the amateurs who are determined to spend their time machining short lengths but refuse to adopt the recognised and simple solution.

JS,I know, has his own Swinglite (and is no doubt a black belt in its use ) and does n't need me to defend him. However it is probably easier for me to say that in my opinion he is far from an ordinary machinist in that his bodges are actually far from bodges and demonstrate good lateral thinking in solving engineering problems that benefit and amuse us all. Also I have for one gained great benefit from his willingness to take the trouble to write up and publish articles on solving model engineers problems e.g. taper turning using a boring head, making gear cutters etc etc. When you add to this the extraordinary efficiency and effort he put into taking up the Chris Heapy site and ensuring its survival, the improvements he has instigated in simple accessories at Arc, and his work at exhibitions sharpening for a charity fee and not least the improvement in the general tenor of the posts on this forum since he became a moderator I can think of few others who do more for model engineering. I speak as one who's efforts in eliminating rivet poverty in the UK failed to be recognised by the Palace.

I could add more but will limit his embarassment. I felt compelled to add this paragraph in view of some extraordinary posts submitted recently. Not that JS is above criticism . I have in the past taken serious issue with him when certain items have been rapidly sold on another website he has connections with ,without his checking with me first as to whether I required the said items . I'm never more than a phone call away. I also never proved anything but there was a time long ago when QCTPs hardly ever appeared on the aforementioned website and I often wondered whether he was trying to corner the market in QCTPs and holders in order to hold us all to ransom. I believe he has more than a few.

Alan Frost (brown belt , pink Swinglite,green engineer)

 

 

 

 

 

Edited By alan frost on 27/09/2016 15:15:25

[alan frostParticipant @alanfrost17805]

If I could be forgiven a short commercial,apart from my unrecognised (but successful) efforts in eliminating rivet poverty in the UK , I now have the means available to commence the project to eliminate ball bearing poverty amongst model engineers in the UK. I know this was one of the major concerns of the Cameron government and as soon as I can get off my backside and classify the bearings adverts will be flooding the country. Toyota at Derby and Honda at Swindon (or is it the other way round ?) have now been satisfied and we now have capacity to release bearings to the model engineer market . As Theresa said to me only yesterday "Thanks, Alan,thats one less problem to lose sleep over".

[Raymond AndersonParticipant @raymondanderson34407]

If you don't understand any of it then fine, you work you're way and I'll work mine. simple .

<redacted>

If you can't be constructive like others, please don't clutter up the thread with inane ramblings. This thread has got zero to do with QCTP's, Ball bearings, or Camerons government.

Edited By Neil Wyatt on 28/09/2016 21:06:15

[AjohnwParticipant @ajohnw51620]

Posted by Michael Gilligan on 26/09/2016 21:11:56:

John,

It's good to see you contributing again, instead of sitting smugly in your corner humming "up yours".

Frankly, however, I don't understand your post … I thought we were trying to clarify something for Gary.

MichaelG.

Sorry if I sounded a bit terse Michael. I was busy with other things so it might have come across a little rude.

Any way all I was getting at is some seem to think that metal has a similar characteristic to rubber which it has but nothing like to the same extent so that if loaded reasonably it can be ignored. Good job too.

The contact aspect is a little more tricky. Say something is in contact and another isn't by 1um and that could be due to a number of factors. Is it gripped so well ? Yes and no depending on finish but clearly as some relatively low level this does matter.

The up yours was just a joke. It comes from having had to explain a number of things to people at times over a large numbers of years. It can be a thankless task in some respects especially when some one is totally locked into their own ideas on a subject.

John

–

[Raymond AndersonParticipant @raymondanderson34407]

Alan, Have you ever felt the weight of a 12" chuck on a DSG? That is where the collets are going and they will be on there long term. Not everything needs a 12 " chuck. I don't mind swapping over the 6 " on me GH750 to ER 40 I do that quite often, but there is a very big difference in weight.

Jason, Steve1, I have made a decision, and am going for the 25c both through bores and there are also emergency ones that can be machined to suit.. Just need to fire off an amended e-mail to Hardinge about the spindle nose [since I have decided on 25c and not the original 16c] I would be just as well to go the full monty and make use of the DSG spindle capacity. rather than regret it later. Be a lot of overtime done to pay for this.

Thanks for all your constructive help.

cheers

[SteveIParticipant @stevei]

Raymond,

Please do let us know what D1-8 25C chuck you go for.

To answer the now redundant question about the 5C sjogren chucks, they used to be made by Hardinge and perhaps others before then but I think they don't make them any more. That line of product was sold to ATS workholding.

**LINK**

Steve

[JasonBModerator @jasonb]

Funny enough Steve I was just looking a guy using the 5C step collets and it looks like he has one of those chucks or something very similar.

**LINK**

Raymond you may be able to get away without teh external rings on the sort of sizes you are looking at, its more the big ones that grip better with the load applied at the outside.

Edited By JasonB on 27/09/2016 17:16:02

[Raymond AndersonParticipant @raymondanderson34407]

Hi Steve1, Jason . First off thanks for all your help with this, it is much appreciated. I have sent an amended e-mail to Hardinge in the UK changing the spec from 16c to 25c As soon as I hear back I will post on here.

Did a quick count up of the collet prices on the us site and they are all in dollars, so a quick conversion resulted in a definite arm and leg scenario, plus I still have to get the price of the chuck !! I think the DSG would warrant it anyhow,. and it will be a once in a lifetime purchase… so best do it right .

Will be quite a bit of overtime done to pay for this thats for sure.

cheers

[Raymond AndersonParticipant @raymondanderson34407]

Just had a look at the speed chuck and it looks a cracker, and is available in D1-8 so no probs there.

I tried the Harding catalogue but could find no reference to 22J Collets although the ATS chuck info says 57.15 capacity. Will see what Hardinge says re the D1-8 for the 25c. If that is a no go then at least I can have the speed chuck in 22 J, that would be a fine replacement.

cheers

[John Stevenson 1Participant @johnstevenson1]

Alan, many thanks for the plug. The cheque is in the post, in fact it’s the same one as last time, just keep presenting it!

[SteveIParticipant @stevei]

Jason,

 

That video link does indeed look like it might be a sjogren speed chuck. However it has the plain nose so you can't use the closers on it. I always use the closers since I have them and I don't fancy any mishaps. Looking at the step collets I have they will contract with out a closer a little but I can't see them working as well as with the closer. I hope he stays lucky….

 

Raymond, the speed chucks come in various flavours, 5C, 2J, 3J, 22J etc. For the 5C they come in the 3 variants.

with the plain, taper, and threaded noses. I only have experience with the 5C-X type. The hardinge website is not the easiest to navigate but this link should hopefully take you to the 22J collets:

**LINK**

 

I don't have any experience with 22J so I can't comment on the suitability.

 

Edit for spelling errors

Edited By SteveI on 27/09/2016 18:00:43

[AjohnwParticipant @ajohnw51620]

Which DSG have you got Raymond ? I did a lot of work on a long bed toolroom version in pristine condition years ago. Wonderful machines. I almost feel like crying when I see some examples on ebay. How dare they get a lathe like that into the sort of condition they sometimes are.

The answer to the big chuck when I worked on lathes like that was a wooden block that the chuck can't roll off that bought it up to the correct height and aligned it well enough. It took a bit of effort to slide it along. At that time I was perfectly capable of handling big chucks – not so sure now. Gravity seems to have increased.

There was a big Lang about as well. Deliberately mall adjusted but not used much and never for long. Adjusted up it was nothing short of fantastic. I have seen which is best DSG or Lang arguments about. CVA's can be pretty amazing too. They also did a CVA with gap bed with a huge swing in it. It seems they based it round one of their spinning beds.

John

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[Raymond AndersonParticipant @raymondanderson34407]

Steve1 Thanks for the link to the 22j. Yes the Hardinge cat is a bit difficult to navigate.

Ajohbw, it is a 17t was not cheap but it is immaculate It was obviously very well looked after. I dont use it much I use me smaller Gh750 more often. Once the collet system is up and running then I will use it more I never really need its capacity but I.had to “snap it up” when I got the chance.
Cheers.
Ps, Ihave been told the Lang lathes were also superb machines. Made in Glasgow I think.

[Michael GilliganParticipant @michaelgilligan61133]

Raymond,

I sent you a p.M. earlier

MichaelG.

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