Burnerd Multisize lathe collet chucks - Keep or sell?

Hi,
Firstly - thanks to all those who took the time to reply to my
previous enquiry (Bridgeport milling questions).
I also purchased an old Colchester Student 6 and this was supplied
with a 3 jaw chuck, a 4 jaw chuck and these (which I'd never seen
before)
formatting link

There are 12 sprung collets, numbered "EC2....EC13", all seem in good
condition - the jaws move freely and spring back with good force.
After a little digging, it appears they're quite highly regarded for
precision work although I'd welcome your comments.
I've only ever used a standard 3 jaw chuck before and this has been
perfectly adequate for my hobbyist needs. I can't forsee any
"precision" work in my future and wondered if I'd be better selling
these and using the money for other tooling.
What do you think?
Thanks & regards,
Mike
Reply to
MikeG
Loading thread data ...
That looks like a real nice collet set. probably worth quite a bit. This set has a HUGE advantage over the more common 5C type in that they grip a range of sizes so you need less collets to cover all possible part diameters.
I use collets all the time, they hold the part right on center. Three jaws often are more than .002" off center when you check. if you have an adjust true type three jaw this can be improved but it will be off again at another diameter. Another solution for accurate work in a three is soft jaws - you bore the jaws accurate first. Both these solutions take way more time than just using a collet.
Your call on whether you need collets. I know you'll have a need for accurate work at some point.
karl
Reply to
Karl Townsend
I bought a set in really good condition, many of the collets looked unused, about 5 years ago for £365 off ebay. They do come in handy but haven't really paid for themselves yet but are nice to have around. If you think you could live without them then possibly invest in a new 3 jaw chuck, first checking the state of your old one. My Harrison M300 came with a 160mm (6 1/4") Pratt Burnerd chuck but it was worn so I bought a new 160mm Bison Toolmex chuck and backplate and have been very happy with it. It was only standard grade but when I checked a test bar for run out at the chuck it measured 0.01mm TIR. I haven't checked further away or different diameters but it has proven more than accurate enough for my needs at the moment.
Reply to
David Billington
Nice collet chuck and collets. Looking at the threads on the back of the chuck, I presume that your lathe's spindle is a L-00 or larger.
Have you ever tried mounting in a chuck something which was already to final diameter in your chuck and turning an extra feature concentric with the existing OD?
3-jaw chucks are known for having noticeable runout when you try to do something like that. If you measure a runout of 0.003" or less on a 3-jaw chuck, you have an exceptionally good one.
4-jaw can be adjusted to tune out the runout -- but it takes time.
In particular, the collet chuck is useful when making multiple parts from bar stock which will fit through the spindle.
My 12x24" Clausing has a lever closing drawbar for 5C collets, and I tend to use them whenever possible, only shifting to a chuck for larger workpieces (the 5C stops at 1-1/8" diameter for short workpieces, and 1" diameter for through feed stock), or when something is of irregular shape or needs to be cut to make an eccentric, both of which call for the 4-jaw chuck.
I would say keep them. (Or sell them to me, if the spindle nose truly is L-00. :-) But you will regret selling them.
What is the size of the EC-13? Is that in mm, or something else. They look larger than my 5C collets. If the count is in 1/8" steps, then you can handle up to 1-5/8" diameter. Maybe even larger.
Good Luck, DoN.
Reply to
DoN. Nichols
">
Mike - keep them - a 3 jaw chuck is not very useful if you want to cut tubing (for example, cutting brass tubing to make ferrules) because it will crush it - a collet will not. So in addition to being more accurate, a collet will do things a chuck will not. Another use for a collet is to hold threaded rod (or some other threaded object) without destroying the threads.
If you figure you will at some point need to buy collets, you are probably better off keeping what you have
Reply to
Bill Noble
Very handy to have collets that will accomadate both hex and round stock. I replaced my 5C setup for the bernerd setup about 10 years ago and could not be happier.
Best Regards Tom.
Reply to
Azotic
The EC2 is marked as: 1/16" 3/16" 1.6mm 4.8mm
The EC3 is marked as: 1/8" 1/4" 3.2mm 6.4mm
and they then increase in 1/8" increments, finishing with the EC13 which is marked as:
1 3/8" 1 1/2" 35mm 38.1mm
Reply to
MikeG
Hi Dave,
Thanks for your reply.
I think I'll keep them. You seem to be a smart cookie and if you paid £365 for a set they must come in handy at some point! The lathe only cost £600 (including the chucks and tooling) so they're not eating anything if I keep them in a draw.
Regards, Mike
Reply to
MikeG
Hi DoN,
Thanks for your detailed reply.
You absolutely nailed it with your comment about adding an extra feature. I turned some spikes for garden lights and missed the rebate on one. When I remounted it in the 3 jaw and attacked it, it was so badly off centre that I had to part it off and start again. At the time, I thought it was just my lack of ability - now I know it was down to lack of "clue" too :-)
Your reply, and other's, have been most helpful. I've decided to keep them just in case.
Kind regards, Mike
Reply to
MikeG
Yikes, £600 for the Student, tooling, and the multisize collets, that's a damn good deal, not far off buy the collets and collet chuck and we'll throw in the lathe. Have they got any more stuff for sale?. I spent many hours on Students (lathes) when I attended the local tech college, they're a nice machine. What sort of condition is yours in?. A mate of mine got a Raglan Little John for £25, he had been looking for a house and the seller had the lathe and needed to get rid of it. My mate didn't buy the house but went back later and haggled over the lathe knowing it had to go so had the leverage to get a good price. I've also heard of similar cases were a garage had to be cleared and lathes were free to anyone that could take them.
Reply to
David Billington
A very nice range. I wonder whether there is an EC1 handling 0 to 1/16"? Anyway -- as it is, it would allow me to use workpieces through the spindle up to 1-3/8" -- the maximum bore of my spindle.
Thanks, DoN.
Reply to
DoN. Nichols
He has collets that fit his lathe? He would be an idiot to sell them quite frankly.
I concure...sooner or later he WILL have a need to turn something that has already been turned and needs to be maintained concentric.
They are worth their weight in gold when you need one.
"They couldn't hit an elephant at this dist..." Maj. Gen. John Sedgewick, killed by a sniper in 1864 at the battle of Spotsylvania
Reply to
Gunner Asch

PolyTech Forum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.