Pros and Cons of the ER collet system

[Raymond AndersonParticipant @raymondanderson34407]

Ajohnw, I think we have cleared up the confusion [ I certainly didn't help with me not being specific ] It was me that mentioned the radial loads are where the er's are at there weakest COMPARED to dedicated milling chucks That was the area I should have specifically mentioned.. even Rego Fix confirmed this. so it isn't "twaddle " They are suited to all normal milling loads but not HPC / HPM. This is what interests me and a few others. Why this should be. Rego Fix had already confirmed that ORIGINALLY the system was developed for high accuracy reaming and drilling.

As far as the workholding goes my biggest in fact "only" gripe with them is the area you mentioned, re short length parts. And that is why I  [after some research ] am going to upgrade to another system probably the c series or such. unless JS can convince me otherwise.

cheers

Edited By Raymond Anderson on 24/09/2016 16:13:20

[Michael GilliganParticipant @michaelgilligan61133]

Ajohnw,

Please read, or re-read, my bullet-point summary [posted 13:52:43 today]

I carefully chose the term 'sub-optimal' instead of 'unsuitable' … Because it reflects the very small level of less-than-perfect performance that we are discussing.

MichaelG.

Edited By Michael Gilligan on 24/09/2016 16:52:43

[SillyOldDufferModerator @sillyoldduffer]

Posted by Hopper on 24/09/2016 12:45:26:

I think this might sum it up reasonably well:

Where "Allowed Region" refers to the size of the head of the pin, I believe. But I may be wrong.

I suggest we need a new thread to discuss this one.

Hopper's graph implies that the information of a physical system, or the information necessary to perfectly describe that system, must be finite if the region of space and the energy is finite.

I don't know what that means, but it must be good for an argument. Which paradox is exactly the opposite of Hopper's point.

Made me laugh anyway.

Cheers,

Dave

PS I am still interested in ER theory.

[Raymond AndersonParticipant @raymondanderson34407]

Dave, I think i'm to "thick " to understand the graph. I'm lost there. I think I will stick to the practical tests, and leave the areas like above to others who will understand them. Then all the results can be put together with the caveat , " if we ever get that far "

cheers.

[AjohnwParticipant @ajohnw51620]

Unless you have rather a lot of HP Raymond I wouldn't get sucked in as far as milling goes. Manufacturers will always come up with new products. One of Rego Fix's looks to be an adaptation of an autolock. Sales people will always come up with reasons for buying anything.

Really to have any milling problems with ER metal has to compress. It takes rather extreme loads to do much in that line. Out of interest I took a look at what Schaublin feel they need to offer. They do offer something more rigid than any typical collet set up with a nut can be – a hole with a bolt going through the side onto the flat on certain styles of milling cutter. The only limitation on that type of holder is the cutting tool. They offer ER also their now rather old collets with a flat shoulder for the nut to press on. Obviously better than ER as the flat can't cause the collet to be pressed off centre as it can be in the case of the ER's tapered top. They are designed to clamp down to nominal sizes only. All little things but they stack up.

Work holding is another problem. Maybe some company do make ER with reduced grip lengths. All it would need is relieving for some part of their length from the back. Normal spring collets work under the assumption that if it's round only 3 contact points will truly go home on the work. The same thing is very likely to happen in other systems. Bit like self centring 6 jaw chucks. Often sold as precision but in real terms are unlikely to make equal contact levels on all jaws. People still rave about them though. My impression is that they were more intended for gripping things like tube that can deform a little and in that case can give a bit more grip.

Personally if I had a larger miller and it took them I would stick with R8. They were designed to allow max utilisation of a Bridgeport. The one I used was fitted with an autolock. They are more convenient in some ways as they self tighten to suit the cut. A real one of those might tempt me but past that if the machine has sufficient power a bolt hole through the side makes more sense really.

John

–

Edited By Ajohnw on 24/09/2016 17:50:06

[SillyOldDufferModerator @sillyoldduffer]

Posted by Raymond Anderson on 24/09/2016 17:46:43:

Dave, I think i'm to "thick " to understand the graph. I'm lost there. I think I will stick to the practical tests, and leave the areas like above to others who will understand them. Then all the results can be put together with the caveat , " if we ever get that far "

cheers.

Not "thick" at all Raymond, just not familiar with Hopper's joke. Why should you be?

He's referring to an medieval theological debate about how many angels can dance on the head of a pin. It's become a metaphor for pointless debate.

The graph is, I think, from a scientific paper that calculated the answer from the Gravitational and Bekenstein Bounds. (Bekenstein Bounds are something to do with Black Holes.) It's a scientific joke. If you ever watch "The Big Bang Theory" on telly, it's the sort of thing Sheldon enjoys.

Theology and modern Physics appeal to a rather small group – it's Nerd Humour at it's finest!

Regards,

Dave

[Raymond AndersonParticipant @raymondanderson34407]

Thanks Dave, No I was not familiar with Hoppers joke. or any of the rest of it. Hopper thinks it is pointless as is his right , others including me don't.. And, as has been said many times before on various threads "if some don't like it then let it pass" don't even comment . There are numerous threads on here that are of no interest to me, but I certainly won't jump in and say pointless I just don't read them, simple really. What interests me and what interests Hopper are different.

Ajohnw, Agreed, the forces we are describing here are certainly not of a CONCERN for me or I dare say anyone on the forum But I do like to find things out [ thats the drawback of having an inquisitive noggin ] Thanks for the info re Schaublin. Would that be a "WELDON shank or Whistle notch that Schaublin mention, as it sounds like it.

cheers

[Neil LickfoldParticipant @neillickfold44316]

Ray, with the ER series for work holding , you can make a set of collets that are only split in the front only. These will hold work pieces without needing a support ring in the back. But are only really any good for a small holding range. From size to about 0.05mm on diameter smaller. It will keep a concentricity of 0.01mm. The other option is to use a collet size bigger than you need and then make a series of split sleeves to hold the parts. The sleeve only needs to have a single slit and depending on the length of part the slit may only need to go 1/2 way to 3/4 down the sleeve.

In my experience with the Hardinge style C collets, they only are any good at size and up to 0.05mm smaller than nominal. At 0.1mm under nominal, they don't hold parts to better 0.01mm . The C series collets , they make blank collets in steel and Delrin. These come with 3 pins for boring to a particular size and geometry required. They are a lot more work to make in the home workshop compared to the simple ER series collets. Orientated collets when bored in position will be as accurate as you can achieve on your machine.

Neil

[Neil WyattModerator @neilwyatt]

It would be interesting to see an FEA of a Clarkson or Osborne collet. I suspect the tool may only be firmly supported at the pin and around the mouth of the chuck, but I stand to be corrected.

[Michael GilliganParticipant @michaelgilligan61133]

Interesting point, Neil

I guess the 'pin' [i.e. the centre location] would provide useful stability.

MichaelG.

[John Stevenson 1Participant @johnstevenson1]

Posted by Raymond Anderson on 24/09/2016 19:02:00:

Thanks for the info re Schaublin. Would that be a "WELDON shank or Whistle notch that Schaublin mention, as it sounds like it.

cheers

Weldon's which incidentally don't mean weld on are the type often just called end mill holders with the side mounted screw and whilst simple they do have known drawbacks.

Firstly they need to be made to a tight tolerance which a lot aren't but more importantly the shank of the cutter also has to be to a matching tolerance and it's an area where manufactures tend to cut corners.

Ideally they should be a tight push fit but too often they will be looser than this with the result that when the side screw is tightened it pushed the cutter off centre with the result that one tooth is doing all the work.

Balance is also a problem. A new one should not have a problem is balanced but if the screw is lost and replaced by a non standard screw then it all goes out the window.

Worse is the cutter, the manufacturer puts a flat on the shank but who's to say how deep and how long ?

In my book, OK for manually hogging on a mill but not for accurate high speed use because of the problems outlined.

[Michael GilliganParticipant @michaelgilligan61133]

Posted by John Stevenson on 24/09/2016 22:41:43:

… who's to say how deep and how long ?

.

Probably these guys **LINK**

http://www.dykehousecompany.com/pdf-catalogs/Weldon1998-R.pdf

Unless, of course, it's a 'clone'

MichaelG.

[John Stevenson 1Participant @johnstevenson1]

Probably more clones that genuine ones Michael given that Weldon is an American company and anybody buying here would be faced with very high import duties from the States when they can buy far cheaper from the EU or the Far East.

[Michael GilliganParticipant @michaelgilligan61133]

Posted by John Stevenson on 24/09/2016 22:59:50:

Probably more clones that genuine ones Michael given that Weldon is an American company and anybody buying here would be faced with very high import duties from the States when they can buy far cheaper from the EU or the Far East.

.

Quite true, John … But that's the essence of the problem that you mentioned.

MichaelG.

[Raymond AndersonParticipant @raymondanderson34407]

Neil L , thanks for the info re the collets, as I said in the thread that JS started "holding short lengths " I'm almost certain to go for the C 16's If they can hold to 0.01mm at the lower end of their range thats good enough for me. The blanks that you mention are they the same as the "emergency " 5 c's [only larger size ] Have you ever used the B60's ? as that was another I thought about, but could well be overkill for my needs. Thanks.

Nice catalogue Michael thanks for the link. I never even knew that Weldon were a make of endmills, always thought it was just a style of shank. good looking gear.

John S I have a few of the Weldon style of endmill holders on ISO 30, 6 ,8 AND 10 Ø they are fairly simple but effective I have noticed one of the drawbacks you mention as regards the "flat" certain short series endmills will have the screw lining up on the flat and some others you either have to push the endmill in further or not so far. They have a nice small Ø head as opposed to me ER 32 and 40 so are nice for getting into tighter access areas. Have you any experience with the B60 collets that I mention on the "holding short lengths " thread.?

cheers.

[John Stevenson 1Participant @johnstevenson1]

TBH Raymond i had to go and look what B60 collets were.

I do have a couple of super spacers that use these collets but must admit I never use them since the advent of CNC so no I can't make any comment other than as they are single split one end they should be OK for the job in question provided the diameter wasn't far undersize..

They certainly are not full length collets as from memory the back end is well oversize.

[Raymond AndersonParticipant @raymondanderson34407]

Thanks john, looks like I will have to do a bit more research before I make a final decision I will have to get this right cos whichever system I change to they are not cheap and it wont be changed again. I just want a sydtem where I can stick in a collet of the correct dia for the part and away we go no plugs no hassle. There are so many types out there that surely I can find one that suits me and like I said on the thred you started at the moment I have the C16 as a front runner.but that could well change.
Cheers.

[Raymond AndersonParticipant @raymondanderson34407]

Its a bit late just now so tomorrow I will stick some pics into the thread ” holding short lengths ” of some collets I made a while back as a test to see if it was feasable.to make me own collets I dont mind making up a load of them If it gets me away from the “plug ” scenario.
Cheers.

[AjohnwParticipant @ajohnw51620]

The problem with the smaller collets that go down to small sizes is the shear number needed. I have a full set of Pultra collets that go up to 1/2" or so. The size range each can hold means that there are rather a lot of them many only of real interest to watch makers.

The Schaublin catalogue can be downloaded off their web site. A little confusing as there is only a multi language version and it looks like there may be others available.

John

–

[Neil WyattModerator @neilwyatt]

I hate to do this folks.

This thread originally started with a discussion of whether or not ER collets were designed for workholding.

Rego-Fix said they were for drilling and reaming, and the case seemed settled.

I just looked up the 1973 patent by Fritz Weber (who invented them).

http://www.google.co.uk/patents/US3861694

"FIELD OF THE INVENTION The present invention relates to a chuck assembly. More particularly this invention concerns such a quickchange chuck which is used in machining operations to hold tools or workpieces by means of inserts or collets. "

N.

[JasonBModerator @jasonb]

Ding, Ding, Round Two

[John Stevenson 1Participant @johnstevenson1]

Why spoil a good argument with the truth ?

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Neil Wyatt on 26/09/2016 20:22:31:

I hate to do this folks.

…

I just looked up the 1973 patent by Fritz Weber (who invented them).

http://www.google.co.uk/patents/US3861694

.

Nice try, Neil [even if I don't believe your opening line]

Unfortunately, that's not the 'ER' patent

See if you can find the one I referenced on page 4

MichaelG.

[Neil WyattModerator @neilwyatt]

Posted by Michael Gilligan on 26/09/2016 21:40:51:

Posted by Neil Wyatt on 26/09/2016 20:22:31:

I hate to do this folks.

…

I just looked up the 1973 patent by Fritz Weber (who invented them).

http://www.google.co.uk/patents/US3861694

.

Nice try, Neil [even if I don't believe your opening line]

Unfortunately, that's not the 'ER' patent

See if you can find the one I referenced on page 4

MichaelG.

Your reference on page 4 said 'find it if you can'… perhaps you could now oblige with a link…

Neil

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Neil Wyatt on 26/09/2016 22:04:08:

Your reference on page 4 said 'find it if you can'… perhaps you could now oblige with a link…

.

Sorry, Neil … I am not inclined to do that

My post on page 4 was a response to someone who was presumptious enough to suggest that I provided some sort of document retrieval service.

Everyone on this forum probably has the same tools as me, at their disposal.

MichaelG.

[Author]

Posts