Pros and Cons of the ER collet system

Utter Tosh, they are for holding nominally round items, tool or stock makes no difference!

I have a Myford Super7 headstock with native ER40 and it's a joy to use - 1m lengths of 30mm bar? - no problemo!

- Nick

Edited By JasonB on 05/09/2016 12:44:46

Nick, Have to disagree there. They were originally designed for toolholding, more specifically Drills / reamers. I use them for a lot of workholding as do many others and they are great , but workholding is not what they were designed for. There are far better collets than ER for workholding. even as a milling chuck they are far from the best , they are super at taking axial loads, but not at their strongest with Radial loads. I like them but am not blind to their shortcomings.

cheers

Edited By JasonB on 05/09/2016 12:45:09

Yet the radial loads on milling cutters are far greater than the axial ones...

Edited By JasonB on 05/09/2016 12:45:31

Neil, thats exactly the point I made. They are at their best when dealing with Axial loads [what they were designed for ] Guhring did a series of tests on the new "Diver " end mill and used various clamping methods and out of the 3 [Hydraulic , Shrink fit and ER] the ER was the least satisfactory. Of course they are fine for what we use them for but that doesn't take away from the fact that they were originally designed for Tool holding. and specifically,Drills and reamers. [axial loads ].

cheers.

Edited By JasonB on 05/09/2016 12:45:48

Sorry Raymond but how do you work out that a collet tightened up onto work one side and two tapers the other side cannot accept radial loads ?

Surely the limitation will be the collet holder or machine bearings and as Neil has pointed out milling loads in the axial plane are far higher.

I do so hope this is not one of those urban legends that gets repeated over and over with no fact.

Edited By JasonB on 05/09/2016 12:46:07

John, I didn't work anything out. I can only go by the Guhring tests [ unless the world class company that is Guhring got it wrong ] The video on you tube provided the evidence. So its not a case of "no fact " .Just type in Guhring Diver end mill into you tube and its in one of the videos by Guhring. And I did not say that they couldn't accept Radial loads, only that the system is not at is strongest with such loads. And it is a fact that the ER system is bettered by hydraulic or shrink fit. Any heavy milling with end mills that iv'e seen are all shrink fit or Hydraulic.

I'm certainly not knocking them as I use them a lot I think they are great I know a lot of cnc lathes with live tooling use them but for rigidity ,hydraulic or shrink fit is better. and before anyone starts I know we as hobbyists dont need to bother about such things. I'm only reiterating the fact that A] They were designed first and foremost as Toolholders and B] They are at their best Drilling / Reaming.

cheers.

Edited By JasonB on 05/09/2016 12:46:34

Found the video on you tube, It is called "Guhring Diver Tool smash". In it the guy from Guhring mentions that the ER system is at its best when the loads are Axial, not so good at Radial forces. Which is what I said. We as hobbyists don't need to consider such things There are better end mill holding systems than ER ,and there are FAR better workholding collet systems than ER . They are great for our needs, very versatile,I like them.

Edited By JasonB on 05/09/2016 12:47:03

Raymond,

So what collet system would you advise for WORKHOLDING that exceeds what an ER can achieve. ?

Edited By JasonB on 05/09/2016 12:47:29

None that would cover the range of each ER collet., but for a specific Ø then some of the "C " Series or The B42 series all these are available in round hex and square [ and depending on which size ] can cater for larger Ø's than the ER system which max's out at 34 mm Ø also the mentioned series can all be bought as Blanks There are also a range from Micro centric [ I think thats the name ] that are also available in Round , Square and Hex I've yet to see an ER in square or Hex. I think the ER system is the jack of all trades but is the best at only one thing and that is Drilling / Reaming.for which it was originally designed for. But like I said I like them and use them a lot and i'm certainly not knocking them.

cheers

Edited By JasonB on 05/09/2016 12:48:04

In which case I think I need to go notify the CNC Co at the end of the road who work solely for Boeing and Airbus that despite spending 5M on new machinery over the last 3 years they have adopted the wrong tool holding and workholding systems

Edited By JasonB on 05/09/2016 12:48:36

I did that and the video didn't have any commentary, just video of the end mill in action. Nor did it mention collets of any sort?

Andrew

Edited By JasonB on 05/09/2016 12:49:04

Andrew if you type in "Guhring Diver End mill smash" that is the video. I even watched it again this morning.!

Edited By JasonB on 05/09/2016 12:49:44

John, If the company you mention does work for Airbus AND Boeing then there is NO WAY they will be using ER for workholding. AND I would willingly put money on it. [and money means a lot to me ]

Edited By JasonB on 05/09/2016 12:50:12

Taking part of a statement out of context and calling it "tosh" isn't really helpful. ER collets were designed for toolholding, and workholding is only a by-product that happens to suit our needs. If you read back in EIM in 2003, you will find that I described how to make an ER32 collet for the Myford lathe, so I can hardly be accused of preaching Thou Shalt Not Use ER collets for other purposes!

Is this the vid

Thanks Jason for moving this to it's own thread. I have e-mailed Rego Fix Re, the ER collet system and what it's primary purpose was. as soon as I hear back it will be posted in this thread.

John, You say that the ER collets are used in a production environment for Workholding ?? Thats where they are even LESS suited . [ Production workholding ] although, I will happily eat humble pie if i'm proved wrong.

cheers.

Raymond,

As far as I know Airbus & Boeing would not specify how a part was held for machining, why would they? The aerospace dwgs I work with may specify manufacturing 'best practice' but they don't go into minute detail.

Tony

Thanks Jason, thats the Video.

Tony, nobody said anything about a company SPECIFYING how a part was held., this debate is purely about the pros / cons of the ER system. I happen to think there is NO WAY a Production company would be using them for workholding and others say they do. There is no mention from anyone about any firm specifying how a part is held and . as you say, why would they ? that is left to the firm making the part [s]

cheers.

I watched the video, not by Guhring, although one of their employees is being interviewed. It's interesting that the hydraulic chuck comes out far worse than the ER collet chuck. The 'high performance' chuck shown isn't specified as to type.

Andrew