1. Home
  2. ⚙ Model Engineering in the UK
  3. taper question

taper question

I have a shaft and quill(?) with some rather nice and solid bearings - runout is unnoticeable on a 0.002 mm dial gauge - which I want to reuse for a home-made mill.

It has a male taper on one end, I think it may have come from a pillar drill, but I am not sure. It has a a pulley and a pair of angle-in thrust bearings on one end, and a single bearing on the end with the taper.

The taper is a bit over an inch long, perhaps 28 mm/ 1.1 inch, and the wide end is 15.93 mm/ 0.628 inches diameter, which would indicate that it might be a Jacobs #33 taper, which (I learn) is often seen on pillar drills.

However, I cannot squeeze the small end, which is 14.75 mm/ 0.580 inches diameter, into the Jacobs #33 taper idea, no matter how hard I try it is still too fat; and it doesn't fit any other Jacobs, B+S, or Morse tapers that I can find either.

Is there another standard-ish taper that it might be? Would I be able to get any useful mill tooling for it?

The shaft is ca 22 mm dia, so I could perhaps bore and ream it into a MT2 female, or something similar - what would be best for a mill? I work on small scale stuff mostly, and do not need capacity (which I can get access to anyway, if needed, so "buying large" is not appropriate advice - besides which, I don't have room).

I am a newbie at this engineering, and especially at milling, so please don't omit the simple stuff in any reply!

Thanks,

Reply to
Peter Fairbrother
Loading thread data ...

In message , Peter Fairbrother writes

From 'Tubal Cain's' book (rounded to the nearest thou. inch)

JT# Large Small Length taper end end inch/ft

0 0.25 0.228 0.591 0.59145 1 0.384 0.333 0.656 0.92508 2 0.559 0.488 0.875 0.98761 2A 0.549 0.498 0.750 0.97861 3 0.811 0.746 1.219 0.63898 4 1.124 1.037 1.656 0.62886 5 1.413 1.316 1.875 0.62010 6 0.676 0.624 1 0.62292 33 0.624 0.561 1 0.76194

But on having taken the trouble to type all of that out I suddenly realise that you want to use it for milling. In my limited experience, tapers in general and chuck tapers in particular just will not take side pressure. For milling, some form of positive restraint in the direction of the axis is essential.

To avoid disappointment I think you are going to have to "think collets". If your shaft is hollow you might be able to think in terms of split collets with a draw bar but which ever way you jump, take lots of further advice.

Good luck.

Reply to
Mike H

First thoughts are that as you're in the UK that it could be a DIN B16 taper which is the same as Morse Taper #2 but you would have difficulty trying it in MT #2 sleeve as it uses the small diameter end of the taper. By careful measurement you could ascertain this, MT #2 has a taper of .04995" on the diameter per inch.

That style of taper doesn't take kindly to side thrusts so wouldn't be suitable for end milling, unless you drilled and tapped the spindle for a retaining fastener. Boring the shaft to take MT #2 is going to leave the spindle fairly fragile and you still have the problem of tool retention. Mills have hollow spindles with drawbolts for this reason.

Don't want to be too negative about your project but I think there small machines available in the UK for reasonable money that a beginner would be better off with..

Tom

Reply to
Tom

PolyTech Forum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.