Hi all,

Just wondering has anyone had cause to attempt to turn an internal morse
taper on a lathe? If so, how much more difficult is it to turning an
external one? Given the horrendous price of machining accessories I'm
considering making an adaptor sleeve up which will be no. 5 MT on the
outside and 3MT on the inside. I think I can handle the outside taper
(just about) but any guidance on the inside one would be very welcome,
cheers. CD.

Cursitor Doom wrote:
Hi all,

Just wondering has anyone had cause to attempt to turn an internal morse
taper on a lathe? If so, how much more difficult is it to turning an
external one? Given the horrendous price of machining accessories I'm
considering making an adaptor sleeve up which will be no. 5 MT on the
outside and 3MT on the inside. I think I can handle the outside taper
(just about) but any guidance on the inside one would be very welcome,

I've cut a few external 1MT tapers for and on my own lathe and they've
worked very well. I would expect internal tapers to only be that much
harder as per any other boring operation.

I use the "set over the top slide by the correct angle" method. Easily
done by mounting a lathe centre between head and tailstock and then
skimming a tool along it with the top slide screw and adjusting the
angle - that way the tool is moving along the same angle as that of the MT.

The work piece is then setup and the cutting down by traversing the top
slide.


--
Scott

Where are we going and why am I in this handbasket?

Thanks for the info. I'm just curious as to how you mount a centre
between centres as it were, given the use of a mandrel is inapplicable
with such an object not having a hole through it? Also, a sleeve such as
I'm contemplating, would it have to be some fancy kind of steel alloy or
could it be satisfactorily made from ordinary mild steel?


I've cut a few external 1MT tapers for and on my own lathe and they've
worked very well. I would expect internal tapers to only be that much
harder as per any other boring operation.

I use the "set over the top slide by the correct angle" method. Easily
done by mounting a lathe centre between head and tailstock and then
skimming a tool along it with the top slide screw and adjusting the
angle - that way the tool is moving along the same angle as that of the
MT.

The work piece is then setup and the cutting down by traversing the top
slide.

Cursitor Doom wrote:
Thanks for the info. I'm just curious as to how you mount a centre
between centres as it were,
given the use of a mandrel is inapplicable
with such an object not having a hole through it?

Funnily enough I was going to type exactly "mount a centre between
centres as it were" in my post but decided to expand in case it wasn't
clear!

My usual dodge is thus: Dead centres are usually left unhardened so that
they can be trued up again in a lathe if required. As so they have a
centre hole left at the end specifically to let them be remounted. So
with a centre in the tailstock, that end would be located straight off.

For the headstock end, clamp up a bit of random stock, face and centre
drill it from the tailstock. Swap the drill for a centre and you can now
mount the template centre between the two ends and it'll be dead square.

However, that only really works for external tapers. For an internal
taper it's the wrong way round; you'd be trying to bore a hole that gets
wider as you got nearer the headstock rather than narrower.

All is not lost, you just need to "measure" from the far side of the
mounted taper. If you've got a test dial indicator (which is a superior
way of testing the angle as one traverses the top slide), they can
usually angle over the top and reach back on themselves although reading
can be a little tricky then!


Also, a sleeve such as
I'm contemplating, would it have to be some fancy kind of steel alloy or
could it be satisfactorily made from ordinary mild steel?

Depends on how much use it'll get. Mild steel is relatively soft so
prone to burrs and will wear in time but if you're careful and not in a
production environment it'll last a lifetime. Heat blueing, of which
I've read but am hazy on, can be used to prevent rusting.

--
Scott

Where are we going and why am I in this handbasket?

Cursitor Doom wrote:
Hi all,

Just wondering has anyone had cause to attempt to turn an internal morse
taper on a lathe? If so, how much more difficult is it to turning an
external one? Given the horrendous price of machining accessories I'm
considering making an adaptor sleeve up which will be no. 5 MT on the
outside and 3MT on the inside. I think I can handle the outside taper
(just about) but any guidance on the inside one would be very welcome,
cheers. CD.

I quite understand and normally support the time rich - cash poor
solution of making things but this is quite a lot of work and relatively
easy to fcuk up.
This
http://www.ebay.co.uk/itm/5-3-MT-MOR...item1e69973745

is less than £16 with post and an option to make a lower offer.

Any good?

Bob

On Sun, 13 Oct 2013 16:22:49 +0100, Bob Minchin wrote:

[snip]
is less than £16 with post and an option to make a lower offer.

Any good?



Er, yes, now you come to mention it, Bob!

On 13/10/2013 14:57, Cursitor Doom wrote:
Thanks for the info. I'm just curious as to how you mount a centre
between centres as it were, given the use of a mandrel is inapplicable
with such an object not having a hole through it? Also, a sleeve such as
I'm contemplating, would it have to be some fancy kind of steel alloy or
could it be satisfactorily made from ordinary mild steel?

Silver steel ?