Milling Taper Identification

I have a milling taper question. I've got a milling head that takes an odd taper as in the attached (rather bad) photo.
http://uk.geocities.com/ snipped-for-privacy@btinternet.com/Machine_taper.jpg The taper angle is 3.5 inch per foot and the size is the same as 30INT. However it holds the tooling in with a cam action on the cutaway in the male taper and has not driving flats/drawbar facility. The tooling has written on it: AP24-7/8 x 30
Any ideas?
Thanks
Charles
http://www.homeworkshop.org.uk /
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wrote:

Charles, Can't answer that it is but I have seen this, in fact I still have a few odd pieces from the old Eriksson Telephone company who used to use this on a series of hand operated production millers. I did have a 3 Morse to this taper chuck at one point, I may still have it, not seen it for a while. Where were various sizes in this taper either side of the one you have.
Can you mod the spindle to take a drawbar or is the design unable to handle this ?
-- Regards,
John Stevenson Nottingham, England.
Visit the new Model Engineering adverts page at:- http://www.homeworkshop.org.uk /
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Thanks John
It just strikes me as a bastardisation of 30 INT but you're right, has anyone ever done it in 40 INT? Why did they do it 'cos the "INT" standard has been around a long, long time. I'm going to do an investgation into the drawbar option - it doesn't look unfeasible from the outside but you never know 'till it's apart. A "proper" 30INT conversion would be best.
Regards
Charles
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wrote:

Never seen a 40 type but that doesn't mean anything. I think it was an early quick change type and the machines Eriksson's had were of the Arboga mill drill format where a drawbar is out of the question as the gearbox is above the spindle. See Arboga on Tony's site. Just had a look and can't see any chucks and the cutters I had I have ground down to 20mm straight to fit an ER collet, the cutout is just visible. I had a load of smaller ones, around a 3MT size but gave those away ages ago.
An alternative would be to buy a 30int to an ER32 collet chuck and grind a cutout into it and swap collets. This will give you far more scope RDG are doing just the chuck for 54 notes plus -- Regards,
John Stevenson Nottingham, England.
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On Wed, 26 Jan 2005 11:17:34 +0000, John Stevenson

Well I've whipped the spindle out now and my digital camera has just gone *flah* and stopped working so no more pics.
However it is possible to bore through the whole spindle - it'll be hard but there is no gearbox in the way! The minimum shaft diameter at the driving end is about 1 1/8". At the tail end (ie behind the driving bearings it's down to about 11/16". What would be the maximum through bore that I could get away with (bearing in mind it's quite meaty at the business end). 30 INT needs a 3/8 drawbar doesn't it?
Regards
Charles
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On Wed, 26 Jan 2005 13:51:32 +0000, Charles Ping

I've seen all sorts, mostly M12 or 1/2" UNC, but certainly including 3/8"W
Cheers Tim
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