Clarke / Warco Major Milling machine drawbar self ejector

[Ian Lee 4Participant @ianlee4]

Can anyone point me towards information / drawings for a self ejector for the drawbar on a Clarke / Warco Major milling machine please

[Ian Lee 4Participant @ianlee4]

[DiogenesIIParticipant @diogenesii]

On the basis that 4 1/2 years late is better than never..

FWIW, a Major with MT..

Decided that a 'ring-immediately-above-the-taper' wasn't going to work for lack of room. Investigating the top of the spindle revealed a recess of convenient dimension to accept 5/8 BSW thread (11tpi) – coarser than I would have liked, but with the reat advantage of being able to be cut in situ without disassembly.

A sleeve nut was bored 10mm, through which was passed the suitably reduced portion of a 12mm drawbar, with a 19mm AF hexagon cross-pinned above to retain it and give a spanner-hold.

Some attempt at concentriicity, squareness and 'fit' are desirable for smooth operation, the spindle bore being long and tight.

It's been fitted for a few weeks and some dozens of tool changes, and has performed faultlessly using a ring spanner c. 150mm long to secure and release the tooling. Nothing has spun and nothing has taken anything harder than my hand to release.

Although at first sight a 1mm land seemed a rather small area with which to eject a morse taper, when circumferential to a 12mm bar it provides a respectable total area that feels both adequate and positive.

It'd be interesting to see if it would hold up for R8 use.

[Howard LewisParticipant @howardlewis46836]

Should be even better on R8 with the steeper taper, so less force needed to separate.

Howard

[old martParticipant @oldmart]

I made the R8 conversion for the Tom Senior self ejecting with a captive drawbar and it has been a great success. I could only do it because there was a convenient cavity in the spindle above the end of the tooling. Also, I could lock the spindle using spanner flats at the bottom end.

 

Edited By old mart on 08/02/2021 20:35:54

[DiogenesIIParticipant @diogenesii]

..those posts / pictures were revisited more than once during the long 'mulling-over' stage, Old Mart, so an overdue acknowledgement of gratitude to you for them – thank you for putting 'em up.

..The Major spindle nose has lug-slots, and once nipped up the sleeve nut is happy stay put and just gripping the tool and using a short cranked ring spanner like a handle makes for quick tool changing, and of course no more rapping with a hammer..

[Chris ChadwickParticipant @chrischadwick43059]

I've recently bought a Warco WM16B milling machine, and it has a built in ejector. If you loosen the drawbar, then turn it a couple more turns it hits the nut / cover arrangement that holds the drawbar in place. Another turn and it ejects the collet holder or drill chuck as the drawbar has come up against a stop at the very top of the spindle.

A bit late, but may help.

[mechman48Participant @mechman48]

Posted by Chris Chadwick on 16/02/2021 07:51:45:

I've recently bought a Warco WM16B milling machine, and it has a built in ejector. If you loosen the drawbar, then turn it a couple more turns it hits the nut / cover arrangement that holds the drawbar in place. Another turn and it ejects the collet holder or drill chuck as the drawbar has come up against a stop at the very top of the spindle.

A bit late, but may help.

Same arrangement on my WM16 gear head version, I believe the same on the WM18 gear / belt versions.

George.

[MeunierParticipant @meunier]

Posted by mechman48 on 16/02/2021 18:13:26:

quote Same arrangement on my WM16 gear head version, I believe the same on the WM18 gear / belt versions.

George.

/quote Not on my 2019 WM18/gear head George, perhaps that's because it's an R8 taper.
DaveD

[old martParticipant @oldmart]

If there was sufficient diameter at the top of the Tom Senior spindle to accomodate a screwed in plug, I would have made a capitve drawbar of the same design as Diogenes II has (see his photos). That design would work with Morse taper spindles which are unlikely to have any steps in the bore.

[Author]

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