Threaded end mills on an ML7

[Kit White 1Participant @kitwhite1]

I have a 1/2" end mill. They have threaded ends on them like this: Whats the best way without spending hundreds of pounds of holding them in my ML7 Myford lathe's spindle? Can I make a holder out of mt2 stock steel bar with a 1/2unf 20tpi thread on the other end which matches the end mills thread, and just fit that in the spindle?

[Kit White 1Participant @kitwhite1]

[mechman48Participant @mechman48]

Can you not get a collet holder to fit your ML7 ?, not that expensive.

George.

[Michael GilliganParticipant @michaelgilligan61133]

Kit,

I think the ideal would be to proceed as you suggest, but also slit the Morse Taper, to make it into a collet. [You would, of course also need a draw-bar] … You should be gripping the plain shank, not the thread.

I have a broadly similar item [in a watchmaker-style] by Crawford Collets, for my BCA.

MichaelG.

[Kit White 1Participant @kitwhite1]

What type? Should it be mt2 or one that screws onto the spindles external thread?

[Anonymous]

Posted by Kit White 1 on 10/01/2016 11:38:15:

I have a 1/2" end mill. They have threaded ends on them like this: Whats the best way without spending hundreds of pounds of holding them in my ML7 Myford lathe's spindle? Can I make a holder out of mt2 stock steel bar with a 1/2unf 20tpi thread on the other end which matches the end mills thread, and just fit that in the spindle?

Are you sure the thread is UNF? Threaded endmills are normally 20 tpi Whitworth, irrespective of whether the cutter is imperial or metric.

Andrew

[davebParticipant @daveb17630]

MT2 collet, available in Imperial and Metric sizes, fits directly into ML7 spindle, will need draw bar or suitable length of studding. Don't bother with the thread, hold the end mill by the plain shank.

 

Edited By daveb on 10/01/2016 12:04:25

[Kit White 1Participant @kitwhite1]

Posted by Andrew Johnston on 10/01/2016 11:52:37:

Posted by Kit White 1 on 10/01/2016 11:38:15:

I have a 1/2" end mill. They have threaded ends on them like this: Whats the best way without spending hundreds of pounds of holding them in my ML7 Myford lathe's spindle? Can I make a holder out of mt2 stock steel bar with a 1/2unf 20tpi thread on the other end which matches the end mills thread, and just fit that in the spindle?

Are you sure the thread is UNF? Threaded endmills are normally 20 tpi Whitworth, irrespective of whether the cutter is imperial or metric.

Andrew

No, I'm not sure. It is 20tpi but probably is Whitworth in that case. Thanks.

[JasonBModerator @jasonb]

As DaveB says just by a MT collet and make a simple drawbar which only needs to be a length of studding, nut and thick washer. Forget about the screwed shank

Edited By JasonB on 10/01/2016 13:17:04

[martin perman 1Participant @martinperman1]

I would agree with the above but suggest that the thick washer be shaped like a top hat so that the smaller dia sits snugly inside the spindle to hold the threaded rod centrally to stop any vibration which could undo the nut.

Martin P

[John HaineParticipant @johnhaine32865]

Or grind a small flat on the cylindrical portion of the cutter shank, drill/ream a 1/2" hole in the end of an MT2 blank, and use a set screw to hold the cutter. The thread is not meant to hold the cutter concentric, it normally screws into the Autolock collet to pull it snug – the collet holds the cutter true.

[Michael GilliganParticipant @michaelgilligan61133]

Posted by JasonB on 10/01/2016 13:16:44:

… a MT collet and make a simple drawbar which only needs to be a length of studding, nut and thick washer. Forget about the screwed shank

.

Definitely easier, and remarkably economical

… I wonder why Crawfords went to all the trouble of grinding a thread inside

MichaelG.

[Howard LewisParticipant @howardlewis46836]

If you are tight on space, use a Morse Taper Collet.

If you wish to hold other sizes of End Mill, Slotting Drill, or workpiece, my advice would be to buy a holder for ER collet holder, and a set of collets. They will definitely come in handy in the future, for holding tools or round workpieces.

Howard

[davebParticipant @daveb17630]

… I wonder why Crawfords went to all the trouble of grinding a thread inside

MichaelG.

Endmills can and often do pull out of plain collets, the main advantage of using them is that the cutter is supported within the spindle so much more rigid, also maximises headroom. A collet CHUCK can extend the cutter 2 or 3" so a bit more bendy and takes up space you may not have on a small machine. The limitation on a ML7 is likely to be the cross slide, it's a bit floppy. If you intend to do much milling on this machine, a Super7 cross slide would be a huge improvement. Drawbar needs to be fairly tight to prevent pull out and keep cuts and feeds light. Dave

[Michael GilliganParticipant @michaelgilligan61133]

Posted by daveb on 10/01/2016 15:56:32:

… I wonder why Crawfords went to all the trouble of grinding a thread inside

MichaelG.

Endmills can and often do pull out of plain collets, the main advantage of using them is that the cutter is supported within the spindle so much more rigid, also maximises headroom. < etc. >

.

Thanks, Dave

I must confess that my rhetorical question was slightly sarcastic … The Crawford Collet [which cost me quite a lot, nearly 30 years ago] has proved its worth, on many occasions, for the reasons you mention. My only regret is that I did not also buy the Metric one.

MichaelG.

[OldMetallerParticipant @oldmetaller]

Hi, slightly tangential question- do these MT 2 collets only close on the diameter stated, or do they, like the ER 32 collets I've got, overlap and close on any diameter within their range?

Regards,

John.

[Michael GilliganParticipant @michaelgilligan61133]

Posted by OldMetaller on 11/01/2016 10:34:13:

Hi, slightly tangential question- do these MT 2 collets only close on the diameter stated, or do they, like the ER 32 collets I've got, overlap and close on any diameter within their range?

.

Good question, John

All the ones I have ever used are only slit one way [like Watchmaker's collets] and are therefore strictly 'single size'.

MichaelG.

[OldMetallerParticipant @oldmetaller]

Thanks for that Michael, you've saved me getting my wallet out!

Regards,

John.

[Nigel McBurney 1Participant @nigelmcburney1]

Hold the end mill in the three jaw chuck,it works,costs nothing,and thats what everyone dud before the various modern collet systems were available,

[Neil WyattModerator @neilwyatt]

Posted by Michael Gilligan on 10/01/2016 14:52:52:

… I wonder why Crawfords went to all the trouble of grinding a thread inside

MichaelG.

An observation – not much point using the screwed shank unless you have an autolock type collet holder of some sort. Two reasons:

1 if it slips the mill could easily screw itself in so hard it will never come out again.

2 if it is screwed in and slips, it we definitely shift axially (or jam) whereas if it isn't screwed in, it may only spin..

Neil

I my Osborn

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Neil Wyatt on 13/01/2016 19:37:49:

An observation – < etc. >

.

Neil,

I's time to come clean:

The BCA uses 11mm shank collets [Crawford 55 pattern] and that special threaded collet takes 3/8" shank milling cutters. Despite the supeb quality, this leaves a very thin wall on a plain bore. … I believe that at least part of the reason they included the female thread was to 'beef-up' the torsional strength in the area nearest the drawbar thread and the keyway.

I love my Osborn too … but it wouldn't fit the BCA.

MichaelG.

Edited By Michael Gilligan on 13/01/2016 21:48:29

[John Stevenson 1Participant @johnstevenson1]

Posted by Nigel McBurney 1 on 13/01/2016 09:26:24:

Hold the end mill in the three jaw chuck,it works,costs nothing,and thats what everyone dud before the various modern collet systems were available,

.

.

Is it April the first already ?

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Michael Gilligan on 10/01/2016 16:31:27:

The Crawford Collet [which cost me quite a lot, nearly 30 years ago] has proved its worth, on many occasions, for the reasons you mention. My only regret is that I did not also buy the Metric one.

MichaelG.

.

I offer the following solely for the amusement of those who are lucky enough to have purchased acceptable quality ER Collets and Holders at today's bargain prices …

I have just been sorting some old paperwork, and found the receipt for the aforementioned special Crawford Collet [purchased New, from Tenga Engineering]

On 11-Feb-1988 : I paid £45.50 +15% VAT

MichaelG.

 

 

Edited By Michael Gilligan on 17/01/2016 13:45:11

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