Hobbymat MD65 – tailstock sleeve thread

[Steve ColeyParticipant @stevecoley62112]

During stripdown and 'maintenence' of my newly aquired old lathe I managed to get the tailstock chuck (mt1) stuck in the sleeve…and of course in gently tapping it out (wellying it) using a bolt I've managed to damage the 1st 3 or 4 threads in the sleeve…cannot now get the spindle to locate..

Does anyone have an idea of what th thread is) It measures a bit less than 11mm when I put the vernier on it..

Or any uselful tips on sorting the threads?

Absolute novice – please forgive me…

Steve

[Steve ColeyParticipant @stevecoley62112]

[Jeff DaymanParticipant @jeffdayman43397]

If you can find a spare undamaged sleeve you could fit that. If you can find a spare screw, maybe you could cut some flats in the sides, like a tap, case harden it, and chase out the damaged sleeve's thread with it.

Failing that, you could measure all dims of the the existing screw carefully, duplicate it via a separate lathe on a piece of 0-1 tool steel, and make a tap as above.

Just my $0.02 worth. JD

[Steve ColeyParticipant @stevecoley62112]

bump

[Michael GilliganParticipant @michaelgilligan61133]

Steve,

Sorry, I don't know the answer; but I have seen mention that Essel stocks some spares.

http://www.mattharvey.com/esselengineering/index.php?option=com_content&view=article&id=48:welcome&catid=36:welcome&Itemid=55

… Might be a useful contact.

MichaelG.

[BazyleParticipant @bazyle]

Sorry, missed this last night, Hang on a tick.

[BazyleParticipant @bazyle]

I can just rotate handwheel and observe the graduations to see it moves 10mm in 8 turns so pitch is 10/8. You can't 'cos the bits don't work but one trick is to get a scrap of soft wood, especially balsa, or plastic sheet can work and screw it into the hole to pick up the thread then remove and measure it over as many indentations oroily marks as possible.

Next measure the bore with the calipers and find it is about 6mm but that is inside the thread. Metric thread depth is about the same as pitch conveniently so we have to add that on twice, once for each side putting us somewhere around 8.5 mm. Well 8mm x 1.25 is a standard metric coarse thread and I can try a bolt. it fits.

You man not have an M8 tap so I suggest find an M8 bolt and file most of it away at the end 6 threads sort of making the end a triangle looking end on with one side threaded.. This gives you a few cutting edges at the right pitch which you can use as a scraper to pick up on the remaining thread and clean it. You are not trying to use this as a tap, just a shaped scraper. When 'better' make another bolt/tap by filing two big flats leaving thread on each side of a thin threaded bit.

Possible alternative if you have a bit of M8 allthread or a long bolt is to insert it from the morse end to pick up the thread so as to guide itself in the scraping cutting action.

[Brian WoodParticipant @brianwood45127]

Hello Steve,

I've sent you a PM [personal message]

​Look in your inbox

Regards
Brian

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Steve Coley on 04/03/2017 16:16:25:

… It measures a bit less than 11mm when I put the vernier on it..

.

Bazyle: Your analysis seems perfectly logical … but Steve's estimate does seems to be rather high by comparison.

MichaelG.

[somewhat confused]

[BazyleParticipant @bazyle]

It could be they changed as mine is one of the early ones I think, green not yellow, but hopefully he can use the techniques to work it out.

[Michael GilliganParticipant @michaelgilligan61133]

[Steve ColeyParticipant @stevecoley62112]

Thanks everyone…..

I sent an email to Stephen Lacey at Essel this morning and he replied by return…on a Sunday…what service.

It seems that there have been 2 sizes – the majority m8..and others are 7/16 x 20 unf…and guess what..mine is 7/16th..

So I'm a bit stuck as I've certainly not got any 7/16 x 20 unf bolts to try Bazyle's technique….

Essel have sleeves and spindles in m8…but that might cause a problem at the other end of the spindle into the handwheel…that looks like its might be 5/16 x 20….

I'm awaiting Stephen Lacey getting back to me about the handwheel thread..and another member has offered to sort it for me if I post the bits to him…trouble is I'm in France….

Thanks again for the comprehensive help.

Steve

[Steve ColeyParticipant @stevecoley62112]

Got it sorted…a friend of a friend had a bolt of the correct size so ground a slot into it and carefully worked it around…took about an hour…did not want to risk further damage, but all is good and it's back together.

Thanks for the help,

Steve

[Michael GilliganParticipant @michaelgilligan61133]

Well done, Steve

MichaelG.

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