Clarkson Autolock vs ER collets

[BazParticipant @baz89810]

Roy M

What you have got sounds like an FC3 adapter. Clarkson made them to fit 5/8 and 16mm collets and also one to fit directly into the small Autolock chuck body

[Michael BriggsParticipant @michaelbriggs82422]

I have Clarkson and ER25 holders, the Clarkson with threaded shank tools is the easiest to use because it is self tightening and has a fixed register. On the other hand ER collets can be used with plain or threaded shank cutters, my advice to someone setting up would be ER.

Regards,

Michael

[John Stevenson 1Participant @johnstevenson1]

Posted by Steamer1915 on 16/10/2015 16:03:49:

I can only think that you are over tightening the chuck if you are breaking out the centres of the cutters. To re-iterate what has been said elsewhere on this forum, there must not be a gap between the shoulder of the nose piece and the main body on the Autolock chuck.

Steve.

Unfortunately that information is well out of date.

It may have been relevant when Clarkson chucks were invented back in 1834 or whenever but in today's climate with predominately all CNC's this is a recipe for disaster.

You set your tool offset, nip it up with no gap as laid out in all the yellow with age instructions, then start milling.

As the cutter self tightens it pulls into the chuck and your offsets all shoot out the window. If we had to use a Clarkson chuck on a CNC we were told and shown why, to leave a small gap and tighten with the spanner, don't leave it to chance to reset itself somewhere down the line.

As Regards Jon is a previous post rubbishing ER for coming loose they you have either bad equipemt or are doing something wrong.

ER's are now the tool holding of choice in this country. Go into any CNC production shop and it's all ER's

Firm up the road from me has a shed load of CNC's, at least five, 5 axis machines and all the reat of the 3 axis machines has a Haas Mini Mill at the side to prep the work.

They only do work for Airbus and Boeing so do you think if there was a better system they would have adopted it ?

[Michael BriggsParticipant @michaelbriggs82422]

Can someone give me a reality check, is this a model engineering forum, I was not contemplating building an airbus.

[FatgadgiParticipant @fatgadgi]

I have one Autolock chuck and a few ER collet chucks with a 30int mount for my manual mill plus the Cnc uses ER. I have never, ever, had a problem with any of the ER chucks slipping (nor the Clarkson come to that).

Some of the ER collet chucks are second hand Swiss ones and some of the chucks and most of the collets are low cost Chinese ones and they are all pretty similar in terms of my expectation of performance. Nothing slips and I do not need to overtighten, just nip them up sharpish against the low gear of the mill. Non of the nuts are bearing jobbies, just plain.

The cnc uses small ER16 collets which I bought directly from China as they were one of uthe few that stated a low runout. Certainly when they were delivered they were reliably reading less than 5 microns TIR in the spindle. Pretty good for cheap collets.

The Clarkson is left with a specific cutter in it and used occasionally, but it's a chew to change the cutter compared to the ER chucks so it doesn't get used often. And they can't be used with plain shanks which limits choice of (cheap) cutters.

I personally wouldn't dream of buying another Clarkson in preference to ER. But we're all different !!!!

Cheers Will

[Steamer1915Participant @steamer1915]

Posted by John Stevenson on 16/10/2015 23:58:57:

"You set your tool offset, nip it up with no gap as laid out in all the yellow with age instructions, then start milling.

As the cutter self tightens it pulls into the chuck and your offsets all shoot out the window. If we had to use a Clarkson chuck on a CNC we were told and shown why, to leave a small gap and tighten with the spanner, don't leave it to chance to reset itself somewhere down the line."

John,

Can you please explain how the cutter pulls further into the chuck when it is already hard up against the centre?

Steve.

[AjohnwParticipant @ajohnw51620]

ER was invented for tool holding. Some feel earlier designs that have a flat end and a short projection are better. Schaublin and others.

The whole idea of an autolock chuck is that the cutter rotating finally tightens the collet by forcing the collet down into the cone on the nut. In fact I have one where the collet wont tighten via the nut. It doesn't have any need to.

LOL Not put very well. If a collet is put into an autolock chuck and the nut fully tightened the collet will still be loose. The idea is to put the cutter in the collet, fit and nip the nut up. There is no need to tighten it excessively as the cutting forces with self tighten it. Some sense is needed as to how much of the cutter needs to project out of the back of the collet. There will probably be some about where the collet can be tightened via the nut so that plain shank cutters can be used in it.

John

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Edited By John W1 on 17/10/2015 09:46:37

Edited By John W1 on 17/10/2015 09:55:02

[IanTParticipant @iant]

Interesting comments about how to correctly set a Clarkson.

At night school (many years ago) I was told to always leave a very slight gap between the body and the nut when setting the tool by my instructors (the wonderful Pete & Norm). We didn't have CNC, so I don't know the reasoning.

Some years later I came across the "yellowed" official instructions referred to by JS. I thought about it briefly and decided that I trusted Pete just as much as Clarkson and carried on doing it the way I'd been shown. I've never had a problem and continue to do it this way.

Regards,

IanT

[AjohnwParticipant @ajohnw51620]

It makes sense not to tighten the nut to a point where it can't be tightened any more as that might lead to the cutter rotating too much when it fully self tightens which would wear the collets out.

I don't use them at home but elsewhere have never had the slightest problem with one.

I did buy a 3 morse one to use at home but a few days later my Dore Westbury turned up and that needs 2 morse. It's still around. I should have sold it early on as I suspect there would be little interest now.

John

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[Neil WyattModerator @neilwyatt]

Posted by Michael Briggs on 17/10/2015 00:27:32:

Can someone give me a reality check, is this a model engineering forum, I was not contemplating building an airbus.

Model engineers have always learned from industrial practice.

Neil

Edited By Neil Wyatt on 17/10/2015 11:26:05

[egaParticipant @ega]

Model engineers have always learned from industrial practice.

But can anyone think of instances where the reverse has occurred?

[David Clark 13Participant @davidclark13]

Hi Michael Briggs Many of us on here have probably worked on Airbus components. I learnt on industrial sewing machine components, many only about 1/2 in square. I later worked on a spare fixture for the Airbus Supper Guppy to hold the wings while being transported. The machining principles are the same, just larger or smaller. I used to use a flycutter with at least a 3 foot swing, again same principles apply. I suspect many members on here who reply to posts have worked in industry.

[KWILParticipant @kwil]

To all those who follow the yellow page instructions for Clarkson Autolock chucks, have you tried it with an 1/8" (aka 3mm) cutter? How many did you break.??

A sensible airgap on the nut (as per JS) and all is well to just nip up.

ER just do not slip if used properly.

Edited By JasonB on 17/10/2015 13:21:25

[Involute CurveParticipant @involutecurve]

I have both, for me its ER every time, and they are very versatile, as JS said if it slips your doing something wrong……

Shaun

[VicParticipant @vic]

The real beauty of the ER32 system for me is the range of fixtures and fittings it can be used with.

[Michael BriggsParticipant @michaelbriggs82422]

Hello Neil and David, points taken. My background has not included any experience of machining though I have always had interests in various modelling activities. I started out in model engineering a few years ago and have found the learning process fascinating and very rewarding. I have been lucky to set up my workshop with a super 7 and a Senior mill at reasonable cost. I am currently fitting a dro to the Myford and have found a neat way to put a scale on the cross slide without obscuring the adjusters and locking screw. When it is finished I will post some photographs in case there are other forum members that may be interested. I realise that this reply is off post, just wanted to say hello.

Regards, Michael.

[Roy MParticipant @roym]

At the risk of flogging this thread to death, precision ER32 collets are now available with an in-built sliding button that engages with the flat on weldon (side-lock) cutters to eliminate any cutter creep. When you see the speed that new cnc's make swarf, and the price tag on some cutters, it's best not to take a chance! RoyM

[David Clark 13Participant @davidclark13]

Model engineers have always learned from industrial practice.

Neil

I did it the other way round. I read Model Engineer in the school library to learn how to become a skilled engineer in industry.

[JonParticipant @jon]

Regarding tool system of choice ER any company worth its salt doesnt use ER where time is money.
Many other systems are favoured notably Emluge, Tormach or the back locking types with double the ER force and types that are quick release with a reference built in so cutters can be swapped over retaining tool heights.

Just a sample
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Those that report no slippage, well — not from the three types forced to use over the years Wabeco, Chester and a better quality Taiwan.

Clarkson If you screw up on to the centre then nip up it will break the cutter. Best way mentioned earlier but used to feel for the cutter on the centre screwing in then back off 1/4 a turn and tighten up. If nip up while its on the centre its pulling in to it wanting to depart the cutter without closing the collet.

[Martin KyteParticipant @martinkyte99762]

Some observations.

If you are not 'red line cutting' both system work well.

I don't see how the Clarkson system can mess up offsets when the cutter starts of up against the internal center .

If the cutting force moves the ER system the offset will change. It is not a dead length system.

Broken cutters may be more to do with cheap cutters than anything else. I have had badly ground threads on screwed shank cutter before now to the extent that they will not actually screw right into the collet without a little trip to the grinding machine to reduce the crests.

regards Martin

[VicParticipant @vic]

I bought most of my ER32 collets from Arceurotrade which I expect are Chinese, Ketan on here can confirm, and I've had no problems with them holding stock in my Lathe or cutters in the Mill. But then I can't even fit a full size engine block on my mill table much less machine it!

Am I in the right place, this is still model-engineer.co.uk isn't it?

[Steamer1915Participant @steamer1915]

Posted by Martin Kyte on 19/10/2015 11:03:08:

"I don't see how the Clarkson system can mess up offsets when the cutter starts of up against the internal center ."

Hello Martin,

This was the exact point (pun intended) that I made in my earlier post. I asked JS pretty much the same question as you have posted above and he has chosen not to reply.

My best regards,

Steve.

[Martin KyteParticipant @martinkyte99762]

The way I see it working, the cutting forces tend to rotate the cutter on the centre which draws the COLLET further into the chuck not the CUTTER. If anything Clarksons are easier to undo because only get as tight at they need to.

Also if I could quote what is possibly the most accurate statement on Wikipedia

"The tightening sequence of Autolock collets is widely misunderstood."

;0)

note the old fashioned emoticon

[Steamer1915Participant @steamer1915]

[John Stevenson 1Participant @johnstevenson1]

Posted by Jon on 18/10/2015 22:46:58:

Regarding tool system of choice ER any company worth its salt doesnt use ER where time is money.
Many other systems are favoured notably Emluge, Tormach or the back locking types with double the ER force and types that are quick release with a reference built in so cutters can be swapped over retaining tool heights.

 

 

A few points.

Firstly the Clarkson / ER argument will always run on, it's akin to metric v imperial / do you turn to a calculated diameter before knurling / can you make sense of Ady's screw cutting charts [ delete as required ]

 

If you have an equipped workshop and a supply of cutter sufficient to last then the Clarkson will fit the purpose very well. I used then for years.

 

However if you are at the stage of starting up then one of the ER series is well worth contemplating for a few reasons.

[a] It's both a work holding and tool holding option so one set of collets and one or a face mounted lathe chuck with give you access to use on a mill and lathe.

[b] Secondly they are no gaps in the holding range, each one, with exceptions on the smaller sizes covers a 1mm range. The very small sizes cover 1/2mm.

[c] There is no difference between imperial and metric so 4 collets 7-6, 10-9, 13-12, and 16-15 can hold eight sizes of popular cutter 6, 10, 12 and 16 plus 1/4", 3/8", 1/2" and 5/8"

They can also securely hold any size drill up to maximum you can throw at them.

[d] Many modern cutters are now being made with no threads and most importantly the shank sizes are the cutter sizes so a modern 5mm carbide cutter is usually on a 5mm shank. Something a Clarkson cannot handle.

 

Steamer earlier queried how a cutter can movce once it's on the centre pip.

The answer is when the cutter tightens up it forces the collet down into the nose and for every action there is a reaction. Even though it is on the pip it's only hand tight and the forces will force it to be pushed back harder onto the pip. It is this uncontrolled movement that causes cutters to break, whereas when you tighten with a small gap the operator decided the clamping force and not the sudden uncontrolled movement.

The answer Jons original quote where he mentions the Tormach system.

I am very, very surprised he mentions this as which being a quick change system it has many drawbacks. Foe a start it's base on a holder fitting into an R8 taper so for a start you have two sources of run out, the Tormach holder and the R8. Both of which are lacking in rigidity.

Users of the system admit that it's possible to overload it and the fact that it's not suitable for any system greater than 2HP says a lot.

 

Martin quoted

 

"The tightening sequence of Autolock collets is widely misunderstood."

 

which should read.

 

"Some of the information on Wikipedia is widely misunderstood" As after all it's an unregulated book of personal opinions.

Edited By John Stevenson on 19/10/2015 12:16:33

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