A Different collet question

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Don,

Welcome to the beginning of an enjoyable learning curve - the people here are mainly a very knowledgeable and helpful bunch so you are in the right place!

The ER number is the maximum o/d of the collet body.

btw NEVER use a milling cutter in a Jacobs (or any other type) of chuck. It will not hold sufficiently tightly, and the cutter will tend to be drawn down into the work.

AWEM

Don

You have the same set up as I do - happy to discuss it with you by e-mail off group if I can help.

If you are within travelling distance of London I recommend joining the Society of Model and Experimental Engineers (SMEE). Bunch of great guys and very helpful. I did their Polly training course last year and learned a lot - it's running again this year.

Be very very careful with the ER 32 collet chuck. As Andrew says, you never hold a milling cutter in a Jacobs chuck becaue they are not designed to resist sideways thrust and (more importantly) they don't resist the pull down force on a milling cutter - it's quite scary watching your cut get deeper as it progresses.

ER collets are designed to hold over a range of diameters. My experience is that the ER32 is difficult to tighten to the lowest diameter, especially on the VMC where there is no spindle lock and especially on the smaller diameters where the collet is very stiff. For example, if you want to use a

1/4" end mill in a metric chuck then you have to use the 6 - 7 mm collet. On my set up I can't tighten an ER32 down to 6.25 mm tightly enough to prevent the cutter moving.

I have the ER32 chuck which came with my mill but I vastly prefer the security of an autolock chuck, where the cutter just can't move under cutting load.

Norman Billingham

Where ER collets really come into their scope is that many of the modern cutters are not working to older specs like grinding a 1/4" shank down to 3/16" or 1/8" then putting a thread on it.

There are more and more cutters made nowdays where the shank = the cutter diameter and no thread. In effect making Clarkson chucks not as universal as ER's

Not looking to start a fight over various work holding methods just making an observation, at the recent Bristol show, Jenny at JB Cutting tools had no threaded cutters on the stand at all.

-- Regards,

John Stevenson Nottingham, England.

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No argument from me John. I use both my autolock and ER32 chucks where appropriate (and an ER25 in my Myford lathe) . I think it's important to point out to someone new to these things that you sometimes have to tighten the ER chucks very tight indeed o get the needed grip. As I said, in the case of a 1/4" parallel shank cutter I can't get my ER32 with a 6- 7mm collet tight enough to grip for milling safely. Now if the chuck had spanner flats or the mill a spindle lock!

Speaking of which, does anyone know a good scheme for fitting a VMC with a spindle lock ? It does seem like an oversight in the design. I tighten my collets by putting a spanner on the drawbar nut but it's a bit of a faff.

(snip)

This subject has been confusing me, how could you not tighten the collet? It's easy, spanner on the chuck body and tighten the collet nut with the C spanner, at least that is what I thought. My 3MT vertex chuck has spanner flats and so I stupidly assumed they all did, I now notice that all of the R8 chuck bodies I can find pictured on the net don't have the flats. Is that the standard for R8? If so, can't you grind some suitable flats on the chuck body where there is no spindle lock fitted? I must admit going by my Vertex chuck it appears too hard to do anything else but grind.

I don't like the BANG that I get when releasing the 6-7mm collet after holding a 1/4" shank cutter so I can imagine that it would be difficult to get it sufficiently tight without a secure locking method. Could go a long way to explain why I was so incredulous at anyone having a cutter pull out of a ER collet, well you learn something new every day.

Best regards

Keith

You can get inch series ER collets, at least on this side of the water.

*LTIP ___________ Andre' B.

Sorry but I have to smile at these metric / imperial collets. J&L being a US company sell the same, ironically the imperial ones are cheaper than the metric ones. But look carefully at Andre's link above. Go to the ER32 and look at the 1/4" one for range - 0.236" to 0.275" which so happens to be 6 - 7 mm :-)

Before Ketan at Arc Euro started stocking these I used to buy the imperial ones from J&L . They used to come boxed 1/4" but the collet was etched 7 - 6 ??

There are some genuine imperial ones that do start at 1/4" as an example but they are costly and special order.

.

-- Regards,

John Stevenson Nottingham, England.

Visit the new Model Engineering adverts page at:-

Crap those are just rebadged mm collets. I know we have some 1/2 and 3/8 collets here and as I remember they were not that big of a deal to get. Have to find out where they came from. __________________ Andre' B.

Continent isolated? ;-))

I learned that at school that you say so if it is foggy and ships can't (couldn't) cross the channel.

Nick

Rumour has it that there is a place called 'Europe' that you get to by going to the bottom of the White Cliifs at Dover, and crossing the water going vaguely south. If the locals don't understand you all you have to do is speak LOUDER.

AWEM

Here is the place we got them from.

This place also has some. Also some how to and why info on collet systems. I got no idea on prices, just that if it costs to much the boss says no. ______________ Andre' B.

And more s - l - o - w - l - y

Regards Kevin

I see, I really understood "continent isolated" the way it has to be understood. :-)) It really makes me laugh and I like it a lot. Makes the Brits very sympathic!

Nick

That little strip of water has saved us from the Spanish with their Armada, the French with shorty Napoleon, and the Germans twice last centuary, and the last three occassions have had the benefit to Europe (them over there that is) of saving them from their home grown meglomaniacs that they failed to control in the first place. Why on earth we would wish to actually join with Europe is beyond me.

And some of them persist in top posting which must surely make them fodder for an SS firing squad !

AWEM

Is Steele a furrin name then?

Nick's good, he winds up the Septics on RCM :-)

Mark Rand RTFM

RCM doesn't take any winding up, they are all clockwork on that list.

.

-- Regards,

John Stevenson Nottingham, England.

Visit the new Model Engineering adverts page at:-

That is history. Thanks god. None of us here can be made guilty what happened then.

England as an island. It is OK. I hope you didn't understand me wrong when I sayed that I lough about "continent isolated". I didn't mean it bad. For me, it expresses the way Brits think in two words. And there is really _nothing_ bad about it. Au contraire! The Brits I have met at Sinsheim steam meeting (next one in January) were all very kind and nice to talk with. No exception.

Like the full quoters with defunct word wrapping? :-))

Nick Now this is going to be a too long OT and I'll quit.