Milling very hard steel

[richard 2Participant @richard2]

[richard 2Participant @richard2]

Although a little late – a happy and "workshoperous" New Year to everyone.

Now the question: When I bought my new mill (Warco VMC vario) I bought a Warco R8 collet chuck with collets to take screwed shank endmills.

I imagine it is very like a Clarkson Autolok.

However, there is no spindle lock on the mill and I had a h*** of a job to unlock the cap yesterday as there are no flats on the chuck either.

just above the top of the screwed shank is a ring about 10mm wide and I thought if I endmilled two flats on opposite sides of this ring I could hold it with a spanner whilst I operated on the screwed on cap.

The ring is of very tough steel and I do not have a carbide cutter; so, what sort of speed and cut should I use hoping that I do not ruin the endmill?

Many thanks

Richard 2.

[BikepeteParticipant @bikepete]

This chuck presumably?

A bit 'brutal' perhaps – but would an angle grinder work to (carefully) put on some spanner flats?

Or is the hole visible on that ring for a tommy bar? If so no need for spanner flats…

Edited By Bikepete on 04/01/2018 18:03:43

[John HaineParticipant @johnhaine32865]

It may be a bit late to say this, but why buy an R8 machine, for which excellent collets are available at low prices that grip like the proverbial, and save you probably 50mm of daylight under the spindle, as well as an extra collet chuck?

[JourneymanParticipant @journeyman]

I take that there are no flats on the spindle either. Perhaps could just open the belt guard and grab the pulley to stop the spindle turning!

John

[David Standing 1Participant @davidstanding1]

That's a job for a grinder (proper one, not angle!).

[Norfolk BoyParticipant @norfolkboy]

Will a C spanner fit that hole?

[Stuart BridgerParticipant @stuartbridger82290]

I have the same Chuck on my VMC. For cutter changing, I tend to remove the Chuck from the mill and clamp it in my bench vice with soft jaws. I do like the idea of grinding some spanner flats though.

[EmgeeParticipant @emgee]

Plus 1 for the "C" spanner

Emgee

[VicParticipant @vic]

How deep is that hole on the side of the chuck, and if it’s not for a tommy bar (provided?) then what’s it for? Could it be used for a tommy bar.

As an aside I didn’t know they still sold these type of chucks. Lots of ER collet chucks out there.

I originally bought an ER32 collet chuck for my lathe but then bought another for my mill. The collets fit in my Lathe, Mill, Spinindexer and collet blocks.

[MuzzerParticipant @muzzer]

+2 for John Haine's suggestion – do what 90% of Mercans do and go for the "R8 collet" system. You end up with almost zero stickout, much improved rigidity and a simpler arrangement requiring no C spanners and indeed no chuck as such. Available from all the usual outlets such as Arc Euro and RDG.

You possibly didn't realise it at the time you bought your machine but very few end mills are threaded these days so you will probably end up paying through the nose over the years if you persist with your current chuck.

Murray

[Neil WyattModerator @neilwyatt]

Looks like a posilock collet holder.

Compatible with Osborn Titanic/Titanic II collets but NOT compatible with Clarkson.

Holds the same sizes of cutters (metric and imperial collet sets available).

Neil

[John HaineParticipant @johnhaine32865]

And by the way threaded end mills work perfectly fine in an unthreaded R8 collet.

[Michael ToppingParticipant @michaeltopping17870]

I have one of those and if used correctly you won't need flats on the body. The end cap should only be nipped up when installing the cutter and then should unlock if you tap the spanner with a nylon mallet or similar.

I wouldn't use R8 collets for holding cutters, the cutter can wind itself out of the collet if you take a heavy cut and ruin the workpiece(or worse put a groove in your bed, rotary table etc). I prefer to use sidelock holders as sold by arceuro and others.

Michael

[brickyParticipant @bricky]

The hole visible houses a screw which stops the collet twisting and you can just get a c spanner to hold.I usually use an ER 32 chuck but I have had a cutter work down and ruin the work on one job so when using large cutters I use the Posiloc chuck

Frank.

Edited By bricky on 05/01/2018 00:14:56

[Tony Pratt 1Participant @tonypratt1]

Posted by Michael Topping on 04/01/2018 22:27:06:

I wouldn't use R8 collets for holding cutters, the cutter can wind itself out of the collet if you take a heavy cut and ruin the workpiece(or worse put a groove in your bed, rotary table etc). I prefer to use sidelock holders as sold by arceuro and others.

Michael

There is no perfect collet system, I used R8 for 35 years in industry with very little problems, you don't lose any head room, cutter can be right up in collet or further down if more reach is reqd.

Tony

[JasonBModerator @jasonb]

The problem I find with a collet straight into the spindle is you can't easily see what you are doing with a small cutter and with a spindle dia of about 3" you may have problems hitting hold down clamps etc. As Tony says there is no one system that wil do everything so you need to use what suits the job in hand

[richard 2Participant @richard2]

Thanks everyone for all the interesting replies.

I'm off out to the workshop and try a "C" spanner.

Yes, I do have an ER32 and collets from 3 – 20mm together with some long series.

Is it not a better idea that the chuck is bottomed and threaded in as in the Warco chuck?

I will let you know how the C-spanner works.

Richard 2.

[I.M. OUTAHEREParticipant @i-m-outahere]

With my ER32 collet holder i usually put the machine in low gear and give the end of the peg spanner a rap with a soft hammer – Even though the collet holder has flats for a spanner I rarely use one . A carbide endmill is not that expensive and it would add some more scope to your mill tooling so may be a worthwhile investment .

Ian.

[Dave HalfordParticipant @davehalford22513]

I use the Osborn system, the spanner is overkill and the collet needs to be no more tighter than the chuck

[Tony RayParticipant @tonyray65007]

Glad I saw this thread. I too have R8 in my Bridgeport clone and it works very well but I'm 5'7 so reaching the hex end drawbar is a challenge without a step. I thought the idea of the Clarkson posilock chuck was that you leave the chuck in the bore and simply change the collet when swapping cutters, all done at low level and probably a faster changeover. You also get the benefit of a positively locked cutter; having a cutter creep out of an R8 when you are milling something precious is not a good experience. I buy my cutter on fleabay and find most are screwed shank, one tip I often buy the odd sizes e.g. 15/32" as they are usually cheaper fine for facing and any job where the cutter dia is not an issue. I also have an ER32, great when you have an odd size shank to hold but otherwise I much prefer the R8 as the clamping torque needed on the ER 32 is very high in comparison. I'm looking at importing one of the powerdrawbar kits from the US.

[Ian S CParticipant @iansc]

I have a similar chuck, but mine has spanner flats above the top ring. I think you'll find that the"hole" in the ring is a grub screw to retain the centre pin that locates the cutter. Maybe try a strap type oil filter wrench, I take it the spindle on your mill does not have a lock.

Ian S C

[larry PhelanParticipant @larryphelan54019]

My Lux mill has an MT spindle system,works fine but if I was buying again,I would go for the R8 system. Much better grip and less overhang, This is known as "Hindsight",very useful if you have it in advance !

[VicParticipant @vic]

Posted by JasonB on 05/01/2018 07:31:53:

The problem I find with a collet straight into the spindle is you can't easily see what you are doing with a small cutter and with a spindle dia of about 3" you may have problems hitting hold down clamps etc. As Tony says there is no one system that wil do everything so you need to use what suits the job in hand

This is true. I have metric and imperial collets for my VMC mill but often use an ER32 collet chuck so I can see what’s going on more easily. Finger collets are handy though if you need more Z height.

[richard 2Participant @richard2]

A C-spanner does the job perfectly;

but I will stick to the ER32 set from now on.

Many thanks everyone.

Richard 2.

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