Accuracy of cheap ER collets

I think most of us would use a chuck of some sort but they are nice to have in the cupboard for that odd occasion wher you need all the Z height you can get, thats why I have a few sizes of MT ones for my mill but teh ER32 gets used 99% of the time..

ER11 are 1/2mm intervals as 1mm intervals would push flex beyond elastic limits in small collets.

I don't have issues with ER40 collets close to lower size limit,

- Nick

I measured the diameter of the top surface, where the end-mill is inserted, and compared the Regofix to the Chinese collets. The surface of the cheap collet was a full 0.5mm larger in diameter than on the Regofix collet. This means that he taper will be "engaged" sooner and the collet compressed more when snapped into the nut. Since the end-mill will fit before the collet is snapped into the nut, the extra compression explains why I can not fit the mill while in the nut.

However, I received another collet chuck and nut yesterday, an this nut is obviously different. Using this chuck, I am able to fit the end-mills in the collets. I do think the collets sits a bit sloppy in there, and they tend to fall out when chaken. Buying collets and chucks from different vendors is obviously not a good idea.

I realize i did some stupid choices; first buying cheap unnamed collets and then buying a chuck from a different place. (The first vendor did not have the correct chuck.) The new chuck is from Vertex, and seem to be of reasonable quality. I have since discovered that a Regofix chuck come at the same price as Vertex. The collets are more expensive though.

The Vertex chuck seems to be of decent quality though. I'd like to hear if others have experience with them.

I think I will resolve this by returning the Vertex chuck, and order a Regofix and a smaller selection of Regofix collets. They are about €23-24 (£20 ish) a piece before sales tax.

Lesson learned: stay away from cheap Chinese junk, better to buy less tools of high named quality.

Thanks for all the feedback.

You say your spindle run out is .0005" can you get a DTI on the MT2 chuck taper when it is in the spindle?

Tony

It's far better to grip something in the collet and rotate that in a V block and check the run out of the fixing. Needs some care but can be done as the collet face can be kept in contact with the side of the V block.

That may indicate the error in the V block so best check that as well with some straight bar.

If some one must check in the mill lower the quill and use a magnetic based stand with a V block aspect to it to clamped to the quill.

Actually checking tapers is a little more tricky and can be a little misleading. The only sure way is test mandrels but our main interest is how accurately it all runs including the collet and tapers.

John

-

Edited By John Stevenson on 07/09/2016 13:13:34

Could also be that the taper in the spindle if off. This would clock true at the wide end where you are getting 0.0005 but if it runs at and agle to teh axis of rotation the top ind of teh taper may be eccentric. Can you get a lever type dti up into the MT2 as far as possible and test that. Ot use a MT2 testbar and see if that gets worse the further from the spindle nose you are.

Thanks for the replies guys;

... 'the taper may be eccentric. Can you get a lever type dti up into the MT2 as far as possible and test that'...

Will give that a try, just assumed that taper would be co-axial to the quill shaft as it is usually part 'n' parcel of the shaft & ground as such . Hmm assumptions.

p.s. must give credit to ArcEuro team for their assistance

Thanks George,

We sent the product back to you on 1^st September 2016. Thanks for posting both sides of the story. We are grateful. Just sorry to learn that you are still facing the same problem.

We are still happy to give you a refund for the item – excluding return carriage, provided it is un-marked, un-used, and returned in its original packaging, along with the spanner which was supplied.

We conducted the tests in the same way as George did, and here are the supporting videos.

This is a test conducted on MT2 SX1LP spindle, before fitting Georges MT2 ER25 Milling collet chuck to it. This has been done in the same way as George did on his 'another manufacturer' mill.

This is Georges MT2 ER25 Milling collet chuck as tested on our machine. Like Geoge, we used a 3/8” collet fitted with 3/8” round stock.

Ian at ARC.

Edited By JasonB on 07/09/2016 16:09:07

Edited By JasonB on 07/09/2016 16:24:18

You will never get anywhere with what you are trying to do Mech........... unless you are prepared to think about it.

If not rather than worry about it's better to use it and see what happens. It would take about 10 seconds to see if a cutter is running out by 0.005" when it is approaching a surface that it has already machined.

John

-

Is it possible you have a burr or bruise up inside the MT socket? That could misalign things although the spindle would still run true.

Neil

You could try a spot of Engineer's Blue on a good MT shank to see if there's a high spot on the spindle taper.

Martin.

I would respectfully advise that your knowledge of Chinese manufacturing units is very limited. Based on your limited experience, to tar everything from China which is cheap, to be 'cheap Chinese junk' is incorrect.

We happen to buy ER products from the same Chinese factory as Vertex, which you happened to find reasonable. ER collets come in about three grades, all of which has been discussed so many times that the same old stuff gets repeated, again and again. in simple terms, these grades are: 1-Crap, 2-General - for manual machine use, and 3-High grade for CNC machine application. We sell the General grade. Howeever, makers and sellers use/abuse these classifications for the holders as well as the related collets.

Without naming names, some of the well known brands in the West also buy ER stuff from specific factories in China. You just have to take my word for it, or choose to believe otherwise. More than 60% of ER world consumption - good, bad and ugly comes out of China, followed by India, and from within Europe/the West to a small specialised extent.

Ketan at ARC.

John Stevenson - you are a very naughty boy!

Norman

Oooooh thats a punch south the waistline that one . .

Posted by John Stevenson on 07/09/2016 16:01:14:
You could use ajohnw's finger and get that stuck and it would then save us having to read all the keyboard diarrhoea.

On the other hand if he and by the sounds of it you knew what they were doing there would probably be no need for this thread.

John

-