As you state Chris, the supplier should be allowed to advise before you witter. So why Didn’t you go down that road first?????

 

  One of the sad results of many who have disposable income to burn is that basic skills suffer due to the ability to throw cash at a problem and expect to become master craftsmen.

 

  The collet system was introduced to allow the fast turnround of material to make vast profits for the engineering company owners. As you have stated in the past Chris, you are part of the human RACE, so your free time to partake in an alleged HOBBY must be somewhat of a dissapointment to have to set up a four jaw.

 

  Did you pay a lot of money for the mentioned set??, The ones from Crawford and the likes never seemed to suffer from these problems, or are we talking Chiwanese???

 

  It REALLY surprises me how the likes of Thomas and Westbury et al managed to produce items that FAR exceed in quality and finish, some of the renditions made with the ADVANTAGES?? of all the latest “Home workshop” technology.

I think one lesson here is to ask suppliers of all this low-cost tooling for a SPEC before buying.  First, you can then check that the spec meets your needs; and also whether the kit meets the spec.  The first might save you hassle buying something unsuitable; the second gives you easy comeback at the supplier.

 

Talking of PGMS by the way, I bought a length of 1″ centreless ground PGMS from a supplier at a MEX a few years ago….it measured 1″ diameter OK, but it wasn’t round at all as I found when I tried to mount it running true in the 4Jaw! 

 

John.

Chris – I think you have a couple of choices.

 

1. Send the whole lot back. You will need to check the spec for 5c collets to see whether they are out of spec BTW. Sometimes one can be unpleasantly surprised.

 

OTOH you are after a set of collets, and it would seem that the collets are OK, apart from this undersize caper.

 

I take the point about making all ones own kit – I did the same. Nothing to do with disposable income merely the desire to have stuff that was dead on. Hence the Quorn, Dore Westbury, Radcliffe topslide, GHT dividing head and various bits from Model Engineering Services. Plus tee nuts and various holding thingys for millsand all sorts. All are absolutely spot on and I mean made spot on. The problem is that many want to make models and not tools.

 

Now I buy tooling, because time is limited – my choice. I have never been let down by Chiwanese but I have always kept away from the real economy stuff.

 

As for quality second hand – well that’s fine too. Except that one can be certain of 2 things – you don’t know how it has been used, and you do know that someone didn’t want it enough to get rid of it, for some reason. 

 

There are, it would appear, to be Pooh Traps either way.

 

 

Back to this collet system.

 

I don’t think you are going to repair the collets, because there will be a pile to do.

 

2 So its down to repairing the chuck.

 

You can bore and sleeve to size in situ – very accurate.

 

Or you could get it metal sprayed and ground internally.

 

The problem is that every time you buy another 5C holder to increase flexibility, you know you will have the slackness to sort before it is usable.

 

 

For my money it goes back, and you buy Vertex kit (which IMO is a good compromise between cost and quality). Shell out the difference, and write off the lost weekend as bad hair days.

 

BTW there is a PM for you ref MEX

Chris – I don’t have it quite in my mind how your system is going to work, but it seems very complex, when the problem seems to be limited to:

 

1. Too much clearance.

2 Potentially varying clearance.

 

The problem is that – as I hope I see it right  – by building in the ability/necessity to adjust – you are losing some of the convenience of collets. True running with no hassle. It becomes self defeating? 

 

If you are to maintain that ease of use, AND be VERY accurate then:

 

Tackling it AAF,  – the varying clearance.  You have to get the collets to a common size.

 

Then, having done that an internal sleeve, bored in situ becomes a good thing.

 

Best thing is to mark up how the assembly was set, so you always install it same way. This is like boring spindles in their own bearings, or always using the preferred key slot for a chuck.

 

I have ER collets. They are in general very accurate, but being compressible, sometimes, at the small size for that collet, trueness does take one or two attempts.

 

My view is that its better to be approximately right than exactly wrong, 

 

So my accuracy tier goes 3 jaw, collets and then 4 jaw/3jaw Griptru when I really really mean business.

 

Given how relatively little you paid for your set of collets, that might be an approach you may wish to consider? (Said he hinting heavily. )

 

(The Griptru is a great luxury – they are wonderfully expensive being made by Pratt and Burnerd. I bought mine along with various other goodies – like a screwcutting gearbox – from a place called Skilmans in Woolwich in 1984 when I bought the Myford. Skilmans had stopped being Myford agents a long time previously and I cleared their remaining stock at clearance prices. I feel no guilt. 

 

If I was going to buy another chuck now I would buy one of those extra precision 3 jaws by Bison, brand damn new. Keep it for high days and holidays. I wouldn’t feel a lot of guilt about that either, not even for an 8″ one for the Chinaman. I would merely thank my good fortune that I had one, and the bank manger for his kindness.) 

 

Not bad smilies these – even has a crinkly chip smile.

No, I can see, if you have all your collets to one size, then it should be a once only adjustment. Wrongly, I had this idea that you’d be making adjustments for several collets

 

I like collets to fit t more than 4 points, but that won’t matter if the work is not too heavy. 

 

I’m also very keen on boring things in situ/in there own bearings if possible. 

 

Just different ways of looking at the problem.

All the above makes fascinating reading. Leaving aside the purely technical bits I have come to the conclusion that the only way of ensuring the sort of accuracies which one needs is to fully understand the principles and, where at all possible, make your own equipment or learn how to true up commercial items. I too have been guilty of throwing money at some problems and have always been at the very least a bit disappointed.

 

I do increasingly thumb through back issues of ME and take much notice of the various text books available, usually written before the advent of far eastern type equipment, I previously found it all too easy to dubb much of the information as outdated and often too much trouble to implement, when most can be done these days by chucking money at shiny new commercial gear – WRONG! 

 

I have recently made several items of workshop equipment from these ‘older’ designs, just to see how they turned out and, surprise surprise they have all been noticably better than similar items purchased new. Of course there are sources of good quality precision equipment, as mentioned above, but the prices are really beyond most of us. My philosophy now, when considering a problem is “can I do it adequately with what I have available? if not, how can I solve it myself? Delve into the information available to all of us and the answer is sure to be there, it will be cheaper and far more satisfying knowing that you have produced the required result by your own initiative.

 

My thanks to all those who have commented above. I think I will emerge a better ‘engineer’ as a result.

 

All the best

John

I think that sooner or later we all get caught out with things like this I had a similar experience with a Denford Easiturn lathe where the 3 jaw chuck would not run true. after trying various other chucks borrowed from friends it became apparent that the cam loc locating taper was oversize. This on a British machine (it had obviously gone unnoticed by the school that owned it for the first twenty years of its life). I cannot see how it is possible to escape products made in the far east and anyway I don’t really want to. I have had few really bad experiences with them and can afford to write them off against money saved on the good ones  and still be well in profit. One other thing about Chiwanese products, I am sure that i heard one importer of such machines saying that Colchester CNC stuff was made in the same factory and can anyone tell me where Myford milling machines are made? The world seems to be full of people all saying that their products are fantastic etc etc … They all lie and just because I’m paranoid it doesn’t mean they aren’t out to get me.

Anyway you have my sympathies  and I am sure you will get there in the end.

from John 1

 

About four years ago I bought spare E16 collet chuck from Chronos.

 

On trying it out with a round  HSS tool bank and on more than one machine it was clear that there was a pronounced wobble – visible to the naked eye!

 

I asked for and got a replacement that had virtually unmeasurable runout ?

 

It was completely unclear to me how the original chuck  could have ended up like this (or how it had passed an inspection).

 

The moral must be that it may not be your fault but that of the particular item in question,unless you are expecting an unreasonable level of accuracy. Above all check before irreversible “remedial action” is begun.

As a first time poster, another Chris with similar problems. I can sympathise entirely.

 

I bought a budget 1/2″ bore R8 collet from a forgotten dealer at a show that was so far out it wasn’t funny. I ended up simply throwing it away rather than confuse it with the good ones. Like a previous poster, I can’t see how this could possibly get past even the laxest quality control.

 

I bought a set of expanding mandrels from a company who’s name is reminiscent of part of a circle and they were best described as ‘rough’. I couldn’t in all honesty return them as faulty but the quality was very poor in that instance and IMPO not reminiscent of the finish they appeared to have in the catalogue.

 

I bought a 6″ rotary table from a company in Devon more at home with woodworking equipment, believing from the catalogue that it was a Vertex item only to discover it was a far eastern or indian copy of far inferior quality. It was adequate (just) for the job it was intended for but I still felt deceived even if by the letter of the law, I hadn’t been. In all cases, had I known what I was going to receive, I wouldn’t have bought. The upshot is that apart from these early sales, I’m extremely unlikely to return as a regular customer.

 

However, the ironic thing is that these bad experiences have become learning experiences. I would now far rather buy quality branded good second hand tooling than touch the latest piece of metal from the Hokey Kokey P’nom Ping machine company, no matter how cheap. It’s also made me perform remedial work to cheap disappointing bought items that, while not always successful, have taking me into areas of engineering I wouldn’t otherwise have ventured. I’m not sure if that is a sufficiently satisfying result to offset the annoyance value and the time needed to be invested but it is a small silver lining to the dark cloud. 

Just a question to the OP, how do you know that at 5 – 6 inches your lathe is running parallel the lathe bed.

I would like to know as I am not sure how one is supposed to check this if there is no prior knowledge to the present chucks accuracy!

 

peter