hardinge 5c collets

Hi all

I have a little problem....

A while ago I purchased a 5c collet holder from Arc and don't get me wrong there is nothing wrong with it. all of my collets fit from all different makes and sources etc except these-

which as you can see are a good make. but these-

which are made by hardinge but stamped differently DO FIT.

the problem being, just after the threaded portion at the bottom, the ones that don't fit are 0.02mm bigger which is stopping the thread from engaging.

hope iv'e explained that ok.

So I need to take off 0.02 or there abouts off the bottom of these colletts.

how would you go about it. I've about a 15 imperial ones that need doing

thanks for any ideas/ advice

regards

Paul

I am guessing these will be very hard material & will have to be ground. Unless anyone else has some ideas.

Steve.

Hardinge invented the 5C collet (the 'C' stands for Cataract which is a company Hardinge bought early on) so one thing you can be sure of is if they don't fit it's not the collet that's at fault. Hardinge are world-renowned for the quality of their collets.

They'll have an internal thread too which you often don't get on reproductions.

There are several external difference sin the last photo, what do they actually measure as the 0.02mm you give does not indicate if the large one is the usual 1.25" or if it measures 1.251"

If they are as good a Pete says then why the different diameters, would have expected them to be to spec.

I don't know Jason but Hardinge are almost the last word in quality for collets. 0.02mm is less than a thou. Probably the collets are in spec but the draw tube is at the lower end of the diameter tolerance.

Hi all

Just to add, i've measured some more collets with a mitutoyo digital calipers and got these results-

arc brand new collet 1.2485" fits

unknown brand old imperial collet 1.2485" fits

taiwan imp collet 1.2480" fits

all the hardinge collets that don't fit 1.2490" with the exception of 1 which measures 1.2480" and it fits

the few hardinge collets in picture 2 that do fit all measure 1.2480"

I have also noticed that my collet stop will not fit any of the hardinge collets, but will fit all the others so i'm assuming the internal thread is slightly different?

regards

Paul

The quoted Hardinge back-bearing diameter is 1.250" so it seems your draw tube is tight.

All the Hardinge collects I checked are at 1.249 or 1.2495.

I have some genuine Hardinge collets on my cutter grinder also some South Bend collets that date back to 1942.

I will check these along with some cheap Chinese ones and report back. I have had no fitting issues with any of them in my 5C collet chuck.

Are you sure its the thread and not the keyway?

My experience with Hardinge is that they are tighter on the keyway than the lower cost varieties. When I got a second hand full x 1/64 ths Hardinge set to replace my x 1/32 imports I had to re-work my holders to suit.

In retrospect i should have just bought the 1/64 ths to upgrade my existing set. Used Hardinge appear to be generally no better than new, mid range imports. Home shop guy doesn't need the everyday use factory durability.

Clive

I've spent a couple of hours in the shed this morning faffing about and I removed the key. There was a small burr where the key protrudes into the cavity? I removed this with emery cloth, and tried the offending collets again, same results as before. although with 4 of them with a little bit of wiggling & waggleing I managed to get them in far enough for the screw to engage and pull the collet in. So it seems Pete Rimmer is right and my draw tube is tight.

On reflection of this, I'm coming to the conclusion it's not worth my while to mess about altering the chuck as all my other collets are fine. And I don't think altering the offending collets to suit would be something I could do. I may as well just buy some more imperial ones from arc or wherever, just for the very rare occasion I may use them.

plus my back stop won't fit as it's a different thread

Unless somebodies got an Idea they are always welcome

thank you for all the replys

regards

Paul

The top collet looks to have some damage on the start of the thread near the key slot. The threads are not hard and can be easily cleaned up with a thread file or a small triangular file. Clean up the treads and try again. I have never seen a Hardinge collet not work correctly but have seen them with damaged threads before. Also check the thread condition of the draw bar as well.

Hi to everyone, especially Paul Rayner.

I am Barry, I started my apprenticeship at Hardinge Machine Tools, Exeter in 1966, ending in 1971. There was a factory in Hanworth Road, Feltham, Middx, but that closed a couple of years after I started. The head company base was Hardinge Brothers in Elmira, New York, USA. I continued to work as a Hardinge fitter building HLV-H centre lathes, a few HC turret lathes, but mainly the DV/DSM 59 range of centre and capstan lathes, as well as all accessories. Finally, I worked in the Drawing/Design Office and left in early 1979 to become a SkillCentre Bench Engineering Instructor. Before I left, I worked on redesigning the American KL pedestal unit to fit the English HLV-H to become "our" KL and updated HC models.

Your pictures show very different designs of 5C collet (known in English factories as a PH92 collet), going by the face engraving/stamping. The top one (5/32" looks correct but the lower one, 9/32" was not made in UK, in my opinion. It may be an American one, the circular collet design with Hardinge stamped through it is not an English factory 'thing'. It has added stampings "O" and "B" - I'm not familiar with this, it could have been made as elsewhere as a copy (Hardinge lathes were copied by a few foreign companies, including a Taiwan company called Feeler but their parts would not fit the genuine factory built machine). The spindle back bearing diameter is nominally 1.2500" with an exceptionally tight tolerance of +0.0001" if I remember correctly. Collet back bearing (you describe as just before the thread), I believe, has a diameter of 1.2498" tolerance of only -0.0003". The body length measures from the 10 degree head angle. Bore diameter max runout is 0.001" at a point 1" from the front face. The spindle collet key entering the back bearing is locked in place with a short, #10-32 UNF, grub screw, and is set for depth of engagement against a special gauge.

Pete Rimmer sounds to be very familiar with Hardinge, I'm sure his opinions are reliable too.

I got round to checking my 5C collets. The South Bend ones from 1942 (no internal thread for back stop) are all 1.2485". My Hardinge metric collets are all 1.2495" a range of cheap Chinese ? collets including some hexagon ones are 1.249"/1.2495". All fit my 5C collet chuck and square or hexagon blocks. I do have to fiddle with the location key on the chuck as it sometimes works loose allowing the key to twist, a dab of threadlock on the grub screw would prevent this.

Hi Barry,

Thanks for you r detailed information, it's great that you have been able to provide some insight into the production of those collets. Tight tolerances indeed.

My interest comes from doing a full restoration of my own Feltham HLV. I had the bed ground and rebuilt the carriage, scraped the various ways and rebuilt the headstock too.

I have a question to ask of you - can you tell us what it is exactly that defines the KL-1 model as opposed to a HLV-H? Is it just a UK designation for a HLV-H? A metric machine? I can't seem to find a definitive answer, I'm hoping that you know.

Pete.

Hey Barry, thanks for the long reply and especially the excellent test specifications. I'd love to continue this conversation with you but this is not my thread. Perhaps when I get some time I'll start one about my own HLV.

P.S I actually had those very test bars you mention in my workshop for a time. I was storing them for the guy who bought them from ZMT. Alas, I didn't have my machine built before he came to collect them but that's ok, I can make my own.

Pete.