Collets

Thanks for the confirmation, Ketan

MichaelG.

Given the effectiveness and relatively low prices of ER collet sets I'm surprised that Model Engineer market machines are not made with native ER spindle tapers. Most especially the round column breed where the inability to raise and lower the head without loss of alignment constrains the user to fit both cutting depth and tool change space within the quill travel range. Seems to me that the complete coverage of a considerable size range would allow larger drills to be held in the collet rather than having to find space for a bulky chuck. Smaller drills would do fine in an appropriately sized chuck needing rather less depth. With an ER native spindle, but still through bored, spindle mounting the milling cutters in side-screw holders with relatively long parallel shanks would provide a bit more freedom in vertical position. Especially with smaller cutters. This approach would seem very advantageous in jobs where relatively large, and so long, drills need to be used on one part of a job and small, short, cutters on another.

Returning to the original topic I would disagree with Ian's statement that the Model Engineer has a wide range of work holding options. In practice the interests of domestic harmony and, probably, adequate nutrition means that every hobby £ spent needs to do the work of 5, preferably 10, so equipment constraints are a fact of life. What the Model Engineer does have is freedom to adjust the manner of working and approach to the job. This freedom can range from creative circumvention of the limitations of multi-purpose equipment when compared to more specialist counterparts though activities that the proper engineering books would consider cheating and on to outright fraud. Whatever works. It helps to have a really good understanding of exactly how the equipment being considered for creative exploitation works and what it was designed to do. It being somewhat depressing when creativity runs out on the second to last cut.

In retrospect the most economic approach for me on replacing my BCA with an R8 spindle square column machine would have been to get a set of side-screw cutter holders rather than the ER32 collet set as I had already decided to purchase a spin-dexer and 5C mount chuck. If my lathe had been fitted with a screw nose spindle a matching thread on a 5C blank allowing chucks to be shared would probably have done just as well. Given the relatively limited range of milling cutter shank sizes used by the average ME i'm inclined to think the flexibility of collet systems is perhaps over-rated and that more consideration should be given to proper exploitation of parallel shank side-screw cutter holders. Main disadvantage is the need to grind flats on the cutters for the screw to grip.

Clive

Can anybody suggest a current source of the 'Chinese non-standard ER style' collets as individual collets to make up my set ?

Andy

I wasn't thinking so much in terms of multitudinous bits of (expensive) equipment for the hobbyist Clive - so much as the many 'methods' of work holding available to us - many of which can take a good deal of time to set up perhaps but not necessarily cost money.

For business 'Time is Money' of course but the hobbyist is generally making one off parts and can usually find some creative way to hold the work if necessary - even if it involves making something else to do it. But from your comments I don't think we actually disagree too much on this. Of course, I will admit to having quite a lot of "engineering stuff" - far more than I really need (or use that often to be honest) but it has been gathered over quite a long period of time, so hasn't really cost a fortune (at least not one that my wife has noticed fortunately).

What else to say? My shed (and all my treasures in it - which my wife sometimes unkindly refers to as "all that scrap"  )  gives me a great deal of enjoyment. You could also point out to your wife (as I frequently do to mine) how much cheaper a 'Shed' is when compared to Golf Club Membership. It doesn't entirely work of course but it does seem to help reduce the general level of 'comment' about my engineering purchases.

Regards,

IanT

Edited By IanT on 02/12/2014 00:47:00

Edited By IanT on 02/12/2014 00:47:26

It's only a tiddler Clive but this one has an ER spindle.

http://www.littlemachineshop.com/products/product_view.php?ProductID=4660&category=

Andy,

Did you ask Chester U.K.?

Its been a while since we handled them. We don't have any to check clearly. If they are as per Jasons dimensions picture, they 'may be' - Chinese Q24-16, where 24 stands for diameter, and 16 stands for - upto 16mm maximum capacity. The only difference i can see between Jasons drawing and manufacturers is the angle. Jasons picture shows 8 degrees, and the manufacturers drawing shows 10 degrees. these are not something we do, and not something we can get, but if you do a search for 'Q24-16 Chinese Collets', it will come up with tons of Chinese suppliers, non of whom will have a clue or full dimensional drawing to give you, so, good luck. This is the nearest information i can come up with, and it is not 100% reliable.

Ketan at ARC.

Vic,

Technically, Clive is correct, and your link is a good example. However, the MT2 version sells more, due to the perceived flexibility of the MT2 by way of available tooling.

Ketan at ARC

Ketan, that drawing was saved from your site, and I also got some individual collect when you had them as clearance items. They certainly fit my holder which came with my X3 from Engineers Toolroom. I don't use that holder much now but it is a bit smaller dia than the ER32 so handy when working close to an edge or chuck etc.

Thanks Jason, that is good to know

Ah well, how time flies.We used to buy them though SIEG in those days, so the measurements were probably taken by us at the time from physical stock, but cant be sure, as don't have any to cross check any more either. Still don't know clearly if they are called Q24 either..

Ketan at ARC.

Ketan, thank you, that gives me a start, I too got some individual imperial collets from you when you had them on clearance and they fit my MT2 holder which indeed came from Chester with my Cobra (X1) mill. The mill has now sprouted an X1L table from you - vast improvement.

Andy

The best of the ER collets are made by the BiG company in Japan. The Australian collet is like an ER series but has an 8 deg included angle not 16 like that of the Rego Fix design.

To make home made specials, the ER32 are easy to make in the home shop.

As to holding power for cutters, the Australian 8 deg included taper have more gripping capability, but the cutter body needs to be engaged for the full length of the collet like that of the ER series.

Neil