Runout on a collet chuck?

"Beats me how LBSC and all ever managed to produce their creations without all the NASA and RR standards we expect of todays tooling to enjoy our hobby."

I am so pleased I am not alone in thinking along those lines. I simply don't 'get' all this fretting about the 'nth' degree of accuracy in my back-shed workshop. I take my hat off to those who can achieve it, and no doubt some models like a gas turbine require it, but my philosophy is if it looks right, fits right and works right then it is right!

Luddites unite.

Regards Ian.

I have bought junk on occasion but hope springs eternal so it is easy to get caught out. Probably best not to risk buying a new set of ER40 collets then, unless I am feeling flush and can afford high-accuracy

best

Robin

Like beer, tastes vary! Percival Marshall was fiendishly clever when he named the magazine 'Model Engineer'. 'Model' has multiple meanings; it appeals to engineers who build to scale and to engineers who wish to be exemplary. It's a broad church. Steam Locomotion is the mother lode, but Model Engineering covers everything from astrolabes to x-rays. To me fretting about accuracy is just one of many ways of enjoying the hobby. So is making kit cars, programming a computer or restoring scrap equipment to full working order.

I admit to being suspicious of motives though. Expecting accuracy from a second-hand Gauge Block Set and an antique tenths micrometer is surely unwise. Triply so if the measurements are taken without understanding the rules! And high-accuracy is probably unnecessary. Better than 1 thou/0.02mm is rarely needed in my workshop because I don't mass produce interchangeable spares. My work is mostly old-fashioned fitting; parts made close to size are used as gauges to adjust dimensions until they fit together. Fitting is more skilled and much more fun than knocking out duplicates with jigs and fixtures.

Dave

I am sorry if my simple query has caused controversy. I have had only a little experience with ER collets and that was using a very high quality collet chuck and collets

I was thinking that it was better to get the best runout I could, on the inside of the collet chuck taper. My new collets are probably much worse than 1 thou runout (have yet to check!). That made me question why I was bothering making the collet chuck and buying collets, when I would normally use a 4 jaw chuck and set that up to a thou or less if I wanted good accuracy.

I suppose that it would give me speed of use, but then I am a slow worker and I simply enjoy what I do.. Made me think that I could have spent the cash more wisely.

Regards,

Andrew.

Pete is partly right about using ER collets for workholding because they were already bought for holding cutters.

For me, the availability of hex and square collet blocks is a major reason for fitting the collect chuck to the lathe. Their use makes creating various flats, cross holes and the like much simpler.

A perfectly good question Andrew and not controversial, just different opinions. OK, given a zero run out on O/Ds and bores of all collet parameters - perfection -now what? Can you ensure whatever dia. material, fits the bore, exactly? A few thou plus or minus change the run out rules so to introduce a further point of dispute, the only true type of collet is the 'Rubberflex' version, grips all diameters to the range of the collet.

Originally intended for mass production of components in industry as were QCTPs and Carbides with everything, the perception of 'essentials' seems to be dictated by the depth of ones pockets containing disposable income.

Len Sparey started a minor revolution.

Regards Ian

Always useful to explore options. My ER collets are mostly used for tool-holding, but every so often they're good for work-holding as well. In my case, mostly when smallish round jobs are moved repeatedly between machines. I have an ER collet chuck for the lathe, and square and hexagonal Stevenson Collet blocks from ArcEuroTrade:

If I did a lot of collet work, I'd invest in a set of 5C collets.  They aren't restricted to round work only, and can grip shorter lengths.  (ER collets need an inch or so of round to grip on.)  ER and 5C both achieve low run-out.  5C are best for work-holding, but costly.  ER are are cheaper because they clamp over a wide range and can be used on both lathe and mill.   Which is most useful depends on the type of work being done, and in that sense run-out is secondary.

Dave

Edited By SillyOldDuffer on 16/09/2023 11:56:04