lathe metalwork

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.

Reply to
Cursitor Doom
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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.

Reply to
Scott M

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?

Reply to
Cursitor Doom

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!

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.

Reply to
Scott M
[snip]

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

Reply to
Cursitor Doom

Silver steel ?

Reply to
Rick Hughes

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