Parting problem – Morse taper

[Steve CrowParticipant @stevecrow46066]

[Steve CrowParticipant @stevecrow46066]

I've just bought a Soba 1MT soft end blank for less than the price of a pint (I do live in London)

A Sherline headstock has half length 1MT taper from the big end so I need to cut off the little end and drill and tap for a drawbar.

Now I assume that the taper end of the blank is hardened and I don't fancy trying to part it with the relatively puny Sherline rear parting tool.

Any suggestions for cutting it? Maybe start a groove with a carbide tool then get the hacksaw out?

I only have a kitchen table workshop and no grinding facility.

Also, doesn't a Cowells headstock use the little end of a MT1? If so, does anybody want the offcut when I'm done?

Steve

[JasonBModerator @jasonb]

Depends a bit on the maker but the "hardened" taper is not so hard that it can't be cut with a hacksaw,

If a hacksaw won't touch it then or has difficulty you will need to anneal it as you won't be able to drill and tap it even if you have cut the end off.

[Thor 🇳🇴Participant @thor]

Steve, it depends on whether the MT1 part is through hardened or just case hardened, may it isn't very hard at all. I have cut a case-hardened shank by using a carbide tool to get through the hard skin before using a hacksaw. It was then possible to drill into the cut end (drill was a bit blunt afterwards). Good luck.

Thor

[not done it yetParticipant @notdoneityet]

Alternatives:

Angle grinder? Do it outside, not in the house! Or get one of those carbide grit blades for your hacksawJust clean it up afterwards.

Depends a bit on what you intend using the item for. If only making a centre for turning ‘between centres’ to gain space it would not need a drawbar.

A pint in London may make it quite expensive!!

Try deepening the drawbar hole? If soft it would possibly reduce the cutting required and if not, it would tell you it needs annealing.

[Roderick JenkinsParticipant @roderickjenkins93242]

A couple of points if I may:

I think the Sherline lathe headstock is the same as on my Sherline /Denford mill and this will take a full No.1 Morse taper. If using the full length 1MT then you will need a smaller diameter drawbar. Mine is 1/4" and holds an ER11 1MT collet chuck nice and firmly. The drawbar need only be a length of studding with a nut.

My experience of blank end arbors is that they are harder than mild steel but not excessively so. I do not think the shank will be any different from the head and they are sold so that you can modify them to your own requirements.

Hope this helps,

Rod

[Steve CrowParticipant @stevecrow46066]

Thanks everybody, this was a cheapy so I suspect it's not that hard. My mill will take a full length taper, it's just I don't want to keep winding up the mill head that far.

It has a tang on the end at the moment.

I'm going to make a slitting saw arbour out of it so I think I'll need a drawbar. I plan to drill the end and loctite a threaded insert into it if that sounds viable.

Steve

[old martParticipant @oldmart]

I have a tiny 7 X12 Chinese lathe at home and was annoyed at the amount of tailstock projecting when the MT extracted. I cut off the MT2 tang from the 1/2" chuck (too big for a little lathe) and drilled a hole in the end of the taper, just large enough for the tailstock leadscrew to enter and a little deeper so a brass plug sits at the bottom of the hole and now I get over an inch of extra travel.

[Howard LewisParticipant @howardlewis46836]

Have just repurposed the arbor from a Jacobs chuck (TIGHT!! )

The Jacobs taper had been turned down to 11 mm parallell witha CCMTO0604 tip, to give something to hold in the chusk. So hard that a new Sandvik hacksaw blade would hardly scratch it. No hope of cutting it. An angle grinder did remove the tang.

A CCMT0604 tip cleaned up the rough end, and a TiN coated centre drill cut into it. Ordinary HSS drills 4 facet ground, did not want to know, even as a 3mm pilot. Have had bad experiences with so called Hard Drills, but this time, they worked. With speed and LOTS of pressure the swarf was blue, rather than the air, (and the OD of the taper ). Opened it up gradually to 12mm, loctited in a plug and when cured overnight, drilled and tapped 3/8 BSW, so ready for use!

Lacking patience, did this rather than ordering a blank arbor, and waiting for delivery.

Howard

Why do I always spot the error just as I hit SEND?

Edited By Howard Lewis on 17/08/2019 22:13:05

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