Removing mt0 centre?

[bugbear6502Participant @bugbear6502]

I suspect the live centre on my Simat has been there for at least a decade, possibly 2 or 3 decades.

The mandrel is bored through to around 2.5 mm, so I can get a punch (of some kind) behind the centre to push it out.

Before applying force, would applying something like PlusGas be helpful?

BugBear

[bugbear6502Participant @bugbear6502]

[bugbear6502Participant @bugbear6502]

While I'm on; the spindle is steel, the bearings simply (precise) holes in the cast iron head stock.

What lubrication should I be using? I'm guessing oil, not grease, since there are oil holes.

BugBear

[Ian S CParticipant @iansc]

I've got a little lathe with similar bearings, and I just use SAE 30 oil which is the oil I use for general oiling in the workshop. It probably wouldn't hurt to give the centre an over night soak. On my little lathe the centres have a radial hole so you can give it a bit of a twist, the spindle is solid, so no punching it out.

Ian S C

[Antony PriceParticipant @antonyprice56876]

Hi Bugbear

Is it possible to take the tail stock off, and upend it to allow a “drip –drip” of easing oil down the barrel, leaving it overnight, perhaps longer?

Warming the whole thing in an oven before starting may also help by expanding the metal sufficiently to allow the easing oil to track down

Don’t be impatient and apply force too early! If para 1 and para 2 fail, go back to para 1 and try again

Tony

[bugbear6502Participant @bugbear6502]

This thread looks very informative – it's a Flexispeed, but very comparable. Lots of shots of how the thing goes together.

http://www.modelenginemaker.com/index.php/topic,4025.0/all.html?PHPSESSID=mcpd8j2pdhdds8taqqbnp5ndq3

(Although I don't have a handy Super 7 to make spares for the little lathe!)

BugBear

[bugbear6502Participant @bugbear6502]

Good $DEITY.

There are two grub screws that hold the back-gear drive wheel and pulley-drive wheels to the mandrel.

To use direct drive, you fix the pulley to the mandrel by tightening its screw. Simple.

To use back gear, you undo the pulley screw, tighten the back gear screw, and cam-in the back gear pair.

If you tighten both screws, the mandrel locks (because it can't go round at 2 speeds at once!)

But If you undo both screws you can just pull the mandrel out! It's only held in place end-wise by the driver wheels…

So the mandrel is now vertical (as suggested), with some plus-gas inside it.

BugBear

[bugbear6502Participant @bugbear6502]

I up-ended the mandrel (the face plate was very handy for this) and dripped some PlusGas down it.

I don't have imperial drill bits, but a 2.5mm would go in, and a 3mm wouldn't. A visit to a friend who runs a bike shop, and a rummage in his scrap bin, gave me an old stainless spoke; the rolled-threaded portion of which would just go in the hole, and it mic'd at 0.123", so I suspect the hole is 1/8".

Having cut the spoke to have only 1/2" protruding, it was very easy to tap out the centre, with the mandrel held in soft jaws in a bench vice.

There was a little rusty discolouration. I can clean the centre easily, but can anyone advise on cleaning corrosion from inside the mandrel without damaging it?

BugBear

[Anonymous]

Either your mic or drills are off. In real money a 3mm drill is 0.118", so it should go in if a spoke measuring 0.123" goes in.

Andrew

[bugbear6502Participant @bugbear6502]

Posted by Andrew Johnston on 09/10/2017 10:27:11:

Either your mic or drills are off. In real money a 3mm drill is 0.118", so it should go in if a spoke measuring 0.123" goes in.

Andrew

You're ignoring the possibility of operator error!

What you say is quite true. I'll recheck for sanity tonight.

BugBear

[Anonymous]

Posted by bugbear6502 on 09/10/2017 11:25:52:

You're ignoring the possibility of operator error!

In the brave new PC world we're not allowed to say that, or even hint at it.

Andrew

[NJHParticipant @njh]

Forget the PC and get an Apple ……… although, thinking about it, I seem to recall that an Apple was the cause of all mankind’s problems,😳

Norman

[Anonymous]

Not that sort of PC.

And since I've miserably failed to get the new iPhone7 I've been given at work to do anything that doesn't involve having to register for iTunes I'll stick to apples from the trees in the garden.

Andrew

[Brian WoodParticipant @brianwood45127]

Bugbear,

The 'proper' way to clean up the socket is with a # 0 Morse Taper reamer. They are rare beasts I should think these days so I would suggest you shape a piece of soft wood to the form of the centre you have removed, soak it in Plus Gas and work it about in the hole while rotating the lathe spindle.

Examine from time to time to see what comes out. Pitting is less of a problem, you want to remove surface proud corrosion products. If you have a drill bit with a suitable MT fitting, try it with marking blue on it to see how well the tapers mate.

Regards Brian

[Frances IoMParticipant @francesiom58905]

I bought a 0MT reamer from tracey tools – not that expensive – I wanted it to tidy up any problems with a Perris lathe

[bugbear6502Participant @bugbear6502]

There was a fault in the micrometer-brain interface.

The rolled thread part of the spoke is 0.098"

BugBear

[Martin King 2Participant @martinking2]

Hi Bugbear, long time no hear about you! Hope you are well. Regards, Martin (mahking51)

[bugbear6502Participant @bugbear6502]

Posted by Martin King 2 on 10/10/2017 17:25:36:

Hi Bugbear, long time no hear about you! Hope you are well. Regards, Martin (mahking51)

Hi there Martin! Just messin' around with tools in my workshop, making nothing but happiness, as usual.

BugBear

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