Milling with a morse taper

If that MT-tool holder has a drawbar, yes. If you mean that you can use mills in a drill chuck. Not at all.

Nick

In article , Alex writes

Alex,

It will be fine *provided* that:

(a) you use a secure means of holding the end mill or slot drill - an autolock chuck or an ER collet holder will work, but a drill chuck is totally unsuitable, the mill will work its way out of the chuck; and

(b) you always use a drawbar to hold the autolock chuck or collet holder securely in the 2MT taper - they will be threaded for a drawbar (usually

3/8" BSW or M10) whereas a drill chuck will hardly ever have a drawbar thread (another reason for not using them).

There are other dedicated holders for mills, which should be OK if they adhere to the same principles.

David

Forgive my ignorance, but I am unfamiliar with drawbars. I have only used morse tapers with tangs that are removed with a drift. What are drawbars and how do they work?

Thanks again,

Alex.

A drawbar is used to hold taper fittings secure in the machine; the sideways/downwards forces of milling tend to knock/pull tapers loose.

It's usually a threaded rod that is screwed into the back of the milling head taper, extends through the (hollow) spindle of the machine and is tightened with a nut bearing against the top face of the spindle. You fit the taper as normal then screw up the drawbar nut. Avoid doing them up too tight - it can be the devil's own job to free a stuck taper :(

A suitable milling chuck for your machine would have a 2MT male taper with a threaded hole instead of a tang; all-thread bar makes an excellent drawbar, as arbor threads tend to differ.

hth Guy

Imagine replacing the tang with some thread. Screw a bar coming from top onto that thread and thus pulling the MT into its seat. The drawbar remains while working.

An MT with a tang will shake loose when milling (side-forces).

Nick

Thanks for all the advice. That all makes sense, I shall have to investigate further. I'm glad I asked, I didn't think it was going to be very safe to put end mills in a drill chuck secured with a simple taper!!

Alex.

You will also (almost certainly) need a washer.

Indeed. A few light taps with a copper mallet may be acceptable to free the taper - lock the quill first. My miller has an extra screw thread on the end of the spindle on which you put a threaded cap to force out the drawbar. (One of those mallets with a copper face on one side of the head, and a roll of stiff hide on the other, is a near-essential accessory for machine work.)

Do check whether it is 3/8 BSW (Arrand, and much other UK stuff) or M10 (anything continental). Also, do clean out the spindle taper with tissue before fitting the male taper in it.

David

Alex,

Look at the Chronos web site, I have a similar machine as you and you can easily purchase metric or English autolock chucks from them. Its also with care amazing the size if cut your machine will take.