Milling Chucks

[John CoatesParticipant @johncoates48577]

Posted by The Merry Miller on 05/01/2011 17:24:07:

POSILOCK MILLING CHUCK SET

 

Can anybody out there cast an unbiased (or biased) opinion about the above.

 

 I bought one of these for my lathe and mill in MT3. Been very happy with it for using endmills and slot drills up top 20mm dia. It was a good price from Chronos and am very happy with their speedy service

[The Merry MillerParticipant @themerrymiller]

Well after all that I’ve gone for it.

 

For £71.70 for the set it’s worth the risk.

[chris stephensParticipant @chrisstephens63393]

Hi Guys,

 Just to add my take on the subject, I have the same or similar “Posilock” se,t in R8, for my mill, but since buying an ER32 set and R8 collets for the mill I have not used it, take from that what you like. A cheap price is only good value, if you are going to use the item!

 

I mostly use R8 collets for milling purposes as they give an increase in table to quill distance, but if I am swapping around between drill bits and milling cutters I use the ER set. I find that the ER set also gives a better table to quill distance than an ordinary drill chuck and a much better distance than a key -less one. Plus of course it will take up to 20mm. 

 

If you are thinking of an ER set go for the 32s, you may loose a size at the small end of the range but gain much more at the big end. The bigger size also gives a better range  if you get a collet holder to fit your lathe. As “they” say size matters.

 chriStephens

[magpieParticipant @magpie]

I will second that chris. I bought a ER32 set just before christmass,with the intention of buying an ER32 chuck for the lathe when funds permit.

 

                  cheers    Derek

[JonParticipant @jon]

Quite agree Chris and exactly see your point, thats why i will not ever have an ER type setup. Ok for tatting about where times not an issue.

Secondly have had to use several proper expensive sets of ER 32 and 25 plus the chinese made stuff- All the cutters drop, whats more annoying is undoing and tightening the things,they bind and grab but dont grip the cutter the same.

Total waste of money those chinese ones, worse than decent ER for binding and cutters dropping.

Cant beat those R8 collets, shame i cant use them. No dropping and can change cutter over within 5 secs!

Next best thing and similar the MT2 and 3 collets. Who ever said they will only grip the exact size is telling porkies. 10mm will grip 3/8 cutters, 3/8″ can get 10mm in.

 

As regards friction on the taper its the opposite, because of that it grips more on the cutter. Will hold tipped cutters exactly like an ER type would = lack of understanding and biasism.

 

Carefull where you buy these from they are available in different threads caught me out on small mill had to make two more draw bars 3/8″BSW and 1/2″. 10 and 12mm seem the norm now but have them any way.

Will vouch for the ArcEurotrade MT3 collets they grip and used to be cheap comparatively 11 years ago, plus you can add to the set over time.

Most of mine on bigger mill have come from Chester which i have every available size metric and imperial to hold 20mm.

[chris stephensParticipant @chrisstephens63393]

Hi Jon,

I think you might have misinterpreted my views slightly. I prefer R8 collets, why wouldn’t I, they were designed by people who know than I, to do the job that I also want them to do. With regard to ER32 I have no problem with their accuracy or gripping power, again they were designed, and standardized, to do a job of holding cutters which is what I also want them to do on my mill. They were not designed to hold work, but we all do and  with a reasonable degree of success. Even the cheapest of collets will hold more securely and with a greater degree of concentricity than the average three jaw chuck and much quicker than a four jaw for similar level of accuracy.

I pick the R8s as first choice because they are the quickest  of all to change cutters and of the extra height that they give and not because of any perceived faults, save perhaps height, in the ER system.

Can you give us the instances of when ER collets have failed you, so that we too can judge them with all the facts at your disposal? 

chriStephens 

[JasonBModerator @jasonb]

 Who ever said they will only grip the exact size is telling porkies. 10mm will grip 3/8 cutters, 3/8″ can get 10mm in.

 

 I suggest you take a look at a few text books. For example Tubal Cain in “Workholding in the lathe” takes four pages to go into great detail about the errors and insecurity of using collets for anything but their nominal size. Not just putting metric sizes into imperial or the other way round but even putting bright mild steel which is usually a few thou undersize.

 

This is why taper collets are sold as fitting one size but ER are sold with a size range which is usually 1.0mm below nominal.

 

Granted you can spread a taper collet to take a larger cutter or over close it to hold a smaller one but as they do not close parallel onto the work or into the taper you will only be gripping on part of the tool and taper. Even with ER collets as said above it is best not to use them with work or tools that are a lot shorter than the actual grip area as this can cause the empty end to close too much and the opposite end not enough.

 

Show me a makers cataloge or test book that says taper collets can hold other sizes and I’ll accept being called a liar.

 

J

 

Edited By JasonB on 08/01/2011 09:12:46

[Chris TriceParticipant @christrice43267]

I’m afraid I winced at the thought of forcing a 10mm cutter into a 3/8th collet. Sorry but remind me not to buy any second hand collets from you. Ouch! You’d be asked to buy a new set of collets where I work. Just because these things can be forced to fit doesn’t mean they should. And I’m not so sure you wouldn’t need to use excessive force to get a 3/8th” R8 collet to close properly onto a 10mm cutter and hold it firmly enough without it wobbling without damaging the collet..

[JasonBModerator @jasonb]

Posted by Jon on 07/01/2011 22:39:02:

 

As regards friction on the taper its the opposite, because of that it grips more on the cutter. Will hold tipped cutters exactly like an ER type would = lack of understanding and biasism.

 

 If you read and UNDERSTOOD what I said you would see that is said clarkson type holders are not really suitable for tipped tooling not ER.

 

Yes Chris I was always lead to believe it was bad practice to use the wrong sioz etaper collets, while one may get away with 5/32″ in a 4mm collet Jon’s example is pushing it a bit

 

J

[James fortinParticipant @jamesfortin46829]

ive used ER32 collets with 20mm cutters for hogging out runs of tee nuts and they coped fine, there was not pull out and they locked very well.

 

james

 

[JonParticipant @jon]

Four sets of MT3 imperial and metric collets are not for sale.

Just implying you can hold 3/8″ in 10mm collet and vice versa for those that have only metric or imperial, granted not right but can be done.

Hands held high on Clarkson, incidently never had a cutter drop using them but a pain to change cutters.

 

I dont have the need to hold jobs in the holding system only cutters and rarely a drill. General drilling the drill chucks go on.

Fully understand parallal internal bore would become a  taper if not correct work hold dia, its downside. MT3 tend to lock up in spindle taper as well on most machines though the small mill i have unscrew 1/4 a rev, tap it out comes the cutter much like R8, the other mills a bitch.

 

[JonParticipant @jon]

The other Chris, thats exactly why i love the R8 and MT3, ultra
quick to change a cutter over plus very little loss of height. Add to
that less parts leading to less runout and less pressure on quill bearings.

 

Regarding cutters dropping in ER and similar that was at work. May well be
down to the brand or make but one set was high quality German supplied 
with a Wabeco CNC mill, the other known from new was bought from Chester
(chinese.)  All of us couldnt tighten either up enough – solid, part way through
jobs might notice cutter had dropped or after job supposedly finished
scrapping many hours of work up to then time and time again.

 

Personally i feel for whats happening when taking a cut, by the time realised somethings untoward, its too late guarantee cutters dropped. Usually pushing it for 45 thou cuts in tool and spring steels with anything over 8mm cutters. If yours are not like this , tell me otherwise.

Any precision work i used to take my own collets in and used with same cutters and materials never ever had a cutter drop even when putting a deeper cut on.

[Chris CrosskeyParticipant @chriscrosskey26628]

Posted by The Merry Miller on 06/01/2011 13:47:15:

It’s weird that Myford still refer to their collets as ER.

 

Anyway we’re back to my earlier post  and almost full circle now.

 

I’m with you Chris on this one.

I will not use my Myford collets for milling and will look again at the Posilock chuck and even the MT2  drawbar collets that Arc Euro sell.

 

Chris, would you use those for 1/2″ cutters?

 I’d probably go for a proper chuck for 1/2″…. I do have some cutters that look like a 10mm version of the FC3 style, they go in a morse adapter but the bigger stuff goes into the Autolocks for me… I used to have a Pozilock and it was very good, I only replaced it when I managed to get a 1 3/8″ non-stick taper Autolock for the Simplimill and it made sense to standardise on the one collet type…

 

chrisc

[John Stevenson 1Participant @johnstevenson1]

What a lot of mis- information in this post.

 

Anyone who says ER’s can’t grip tools then goes on to say you get fit a 10mm cutter into a 3/8″ collet is talking out their hat . Probably a wood worker.

 

Showing pictures ofMT2 collets and labelling them as ER’s ? 

 

ER’s are relatively new, invented in Switzerland in 1973 so they have had some catching up to do but are now the de-facto in industry in the UK and Europe.

 

America is still playing with the crappy, wimpy R8 but slowly adapting to ER’s as well.

[JasonBModerator @jasonb]

As I woodworker I wouldn’t like to put a 3/8″ cutter in my 10mm router collet and run it at 20,000+rpm but some try it especially a smost of teh time to ecutter is at crotch level

 

J

[VersabossParticipant @versaboss]

Many thanks John Stevenson for your clear words and keeping the sanity up. I was thinking the same, but have not enough knowledge of the correct expressions for this c**p (yes that I know).

Maybe there are people tightening the collets with bare hands…I can’t remember a single case where I had a cutter moving in a ER. It happened in the front gripping Deckel collets, though. 

Btw, aside of the ER collets which are discussed here  with many slots and a large gripping range, there are also EX types with only 2 x 3 slots and which grip ONLY the nominal diameter. In my Schaublin catalog the ER type is called  ESX.

And a second btw: I was visiting the Myford site lately and NOWHERE they use ER in connection with their Morse collets (I used the search function of my browser).

Think of it what you want… I do!

Greetings, Hansrudolf

[Chris TriceParticipant @christrice43267]

I use ER 25, R8, MT2 and Autolok collets and must confess I’ve had cutters shift in all of them except the Autolok (unsurprisingly). In all cases, it’s been a case of insufficient tightening (obviously) on my part although it’s surprised me on occasion given the amount of tightening torque I’d applied. I’ve also used the Myford deadlength quick release collets but only for work holding. I’ve used the MT2 collets, both drawbar type and front closing ring, in the Super 7 spindle and when the lathe is fitted with the Rodney vertical miller. The one thing that bothers me a bit is that the drawbar type have to be pulled very tight to be sure, which then involves a hefty whack to release them. I’m not sure this does spindle bearings any good. I’ve also got the myford ER conversion nose piece chuck which I might move over to given what’s been written here and also to save the internal taper of the Myford spindle which can get scored if there’s any slippage of the collet despite being hardened.

[Ian S CParticipant @iansc]

I have a Rexon vertical mill, with 3MT, the end of the spindle is threaded, and supplied with the mill is a threaded ring.  To remove the collet chuck, I loosen the draw bar and unscrew the ring, pushing the taper out of the spindle. Don’t blame me if I’m doing it wrong, but I’m 100 per cent self taught, the machine, although bought new, had no instruction, or any other book with it, but I feel better doing this than wacking the draw bar. Ian S C

[Chris TriceParticipant @christrice43267]

Hmmm, that’s a good idea for my Schaublin 2MT ER collet adapter. Got me thinking now.

[The Merry MillerParticipant @themerrymiller]

For the benefit of those who have not come across the Myford ER collet range, Versaboss included, click on the link below.

It also includes the Myford patent range of MT2 collets .

 

 

http://www.myford.com/section4-collets.html

[The Merry MillerParticipant @themerrymiller]

Now I have got the 2MT Posi-lock chuck up and running I’m a bit concerned about the force of impact  I needed to remove the chuck from the headstock spindle when thumping on the exposed end of the drawbar..

 

I’m using an improvised drawbar of 3/8″ whit studding at the moment which is fully engaged inside the chuck 2MT ( I do intend to make a more rigid drawbar later)

 

My concern is that the impact is being referred back to the headstock spindle rear bearing (the lathe is a Myford ML7-R) and I’m not at all happy about that. (that’s the impact not the lathe)

 

The alternative to axial impact is to use a spanner on the small flats on the chuck and impart radial welly, I’m not very excited about that either. 

 

Until I get my new workshop and install a proper mill I have to live with the gear I already have

so comments and/or suggestions will be very welcome.

[The Merry MillerParticipant @themerrymiller]

I’ve just been looking at the Hemingway fitted drawbar, you still have to thump it.

[JasonBModerator @jasonb]

Have a nut on the spindle that will clear the MT 2 taper then wind the nut off and it will push the chuck with it.

 

Jason

[The Merry MillerParticipant @themerrymiller]

Good’n Jason.

If you pardon the expression, jacking it off is just the job. Just tried it with a small catchplate and a peg spanner.

Edited By The Merry Miller on 16/01/2011 21:06:50

[Ian S CParticipant @iansc]

The nut I use for removing the chuck with I think has some thing to do with a 3Mt to 2MT adapterthat came with the mill.  Do most, or all small mills have a thread on the spindle nose, the only other thing I use it for is a large flycutter, maximum dia of cut 6″. Ian S C

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