Coronet Major - morse taper stuck

[disco_monkey79]

Hi

As per the title, a 4-prong drive has got stuck. I've tried twisting with grips, but it's just chewing the steel of the drive.

I understand that some lathes use a long thin drift that pokes in through the headstock to tap them out. However, the hole in my Coronet looks way too small to accept anything robust enough to do this - it's wire coat hanger-type of diameter.

Is this the approved method for the Majors? I could try to buy a bit of steel that skinny, but it seems like it'd be a waste of money. Do I need to persevere with grips and Plusgas?

Once the thing's free, I'll try to get a big nut to go on the threaded section behind, so I can use that to "pop" the M/T bits free. Hindsight's a wonderful thing...

Thanks!

 

[Blockplane]

Surprised you can't get a decent size rod through your mandrel - I've been using a 'Knocking out rod' with no probs all the time I've had mine.

There are proper thread protector -cum -centre ejectors available - take a look on the auction site the mods don't like us mentioning, or phone Mr Pyatt, but they cost about 30 quid a time - ****** that for a game!

 

[SVB]

Can you get a bit of scrap timber onto back of drive centre to hit with mallet and drift it free? Alternatively, can you get an open spanner behind head of centre to lever against nose of headstock spindle?

Photo would help.

Best of luck,

Simon

 

[kevinlightfoot]

There should be a morse taper release sleeve already on the threaded part of the shaft on the headstock spindle,if that is missing you need to source one or get one made,however this does not solve your problem.I think you will find that the spindle is not bored all the way through so even if you bought a small diameter length of steel I don't think that would solve your problem either.In the first instance I would try lightly tapping the drive centre around its diameter whilst revolving the shaft,light taps may vibrate the centre loose.If that fails then you may need to gently heat the shaft with a blow lamp and repeat the tapping,release fluids won't be of much use in my opinion.Good luck and if I can think of anything else in the meantime I will let you know.

 

[Blockplane]

Just out of interest, which version do you have? The older 7/8" x 16tpi, or the newer 3/4" X 16tpi.

 

[disco_monkey79]

Thanks all.

It is possible to tap the drive with a drift, but it's at a bit of an angle, so not sure how effective it is. Levering with a spanner is a good idea, I'll try that with a bit of heat.

Thanks again

 

[kevinlightfoot]

Just clarify for me please is the spindle hollow or not?

 

[disco_monkey79]

I believe it's the 3/4 x 16tpi, as that is apparently what my old Clarke was, and the faceplate etc are interchangeable.

The spindle has a hole at the back, but I don;t know if it goes all the way through, as I don;t have anything small and sturdy enough to poke through... no jokes, please ;-)

Thanks again

 

[selectortone]

I just had the devil of a job freeing a small faceplate on my Axminster lathe today. When I started turning this afternoon, and mounted the faceplate, the temperature in my workshop was 4C. It was 12C by the time I wanted to remove it and it was stuck solid on the spindle. I did get it off eventually but it was a struggle and demonstrated the limitations of the little pin thingy you get with the AT1628VS to secure the spindle - it kept falling out. I've had similar problems on very cold days and I suspect the different expansion rates of large and small lumps of metal cause problems at this time of year.

Possibly a little heat to even up the temperatures of your drive centre and your spindle might help. Good luck!

 

[woodpig]

You may need to make a metal wedge to persuade it to come off!

 

[LancsRick]

Mallet and drift is what I do on the tailstock on mine, but for the headstock you should have the thread protector fitted that you can use with a lever?

 

[Dalboy]

I have in the past used two hammers one is held against the drive underneath and with the second give the top of the drive a sharp tap. Please note I said tap do not hit it hard The bottom one will help stop putting strain on the shaft. It may take a few taps but if you rotate the shaft after each tap it should free up. Then buy a protector/extractor before putting anything else into the morse tapper.
This may sound brutal but if done right will not cause any problems

 

[SVB]

I just had the devil of a job freeing a small faceplate on my Axminster lathe today. When I started turning this afternoon, and mounted the faceplate, the temperature in my workshop was 4C. It was 12C by the time I wanted to remove it and it was stuck solid on the spindle. I did get it off eventually but it was a struggle and demonstrated the limitations of the little pin thingy you get with the AT1628VS to secure the spindle - it kept falling out. I've had similar problems on very cold days and I suspect the different expansion rates of large and small lumps of metal cause problems at this time of year.

Possibly a little heat to even up the temperatures of your drive centre and your spindle might help. Good luck!

Some folks use a leather / thin fibre washer that prevents metal / metal contact stopping this problem.

Worth a try if a repeating problem.

S

 

[selectortone]

Some folks use a leather / thin fibre washer that prevents metal / metal contact stopping this problem.

Worth a try if a repeating problem.

S

Thanks... great tip. I'll bear that in mind.

 

[dickm]

Some folks use a leather / thin fibre washer that prevents metal / metal contact stopping this problem.

Worth a try if a repeating problem.

S

Thanks... great tip. I'll bear that in mind.

But that can't work for MT fittings. Only useful against the register behind the nose thread.

 

[Robbo3]

DM - if you had added a rough idea of where you live, someone might have offered to pop round & help you out.

I thought the Coronets had hollow headstocks but it's a long time since I had one so I may be misremembering.
There are a number of Coronet owners on the forum - perhaps one of them would care to confirm

If you need wedges they are available from Arc Euro Trade £5.74 + £1.25 P&P. I use them for removing the interchangeable tips from revolving centres
- http://www.arceurotrade.co.uk/Catalogue ... dges---NEW

If you need a washer (although their use is frowned upon by engineers), make your own from a plastic milk carton. The plastic is probably the most consistant in thickness you are likly to find in the home.

 

[Blockplane]

Have just measured my knocking out rod* - 6mm dia x 10". I have the older version with 7/8" x 16tpi mandrel nose, but doubt that Coronet would have changed the mandrel bore when they revised the nose thread.

* I am well aware that I have laid myself open to various rude comments there, but that is what it is commonly known as - "it's all in the mind"

 

[Phil Pascoe]

If you can borrow a small gear puller you might be able to put a post of some description in your banjo, centre it over the bed to support the puller and pull it.

 

[kevinlightfoot]

Have you got it out yet?This drive centre seems a stubborn beggar,I'm losing sleep!

 

[disco_monkey79]

Hi

Sorry for the radio silence - been far too cold and dark to venture down to the workshop after work, so I'm going to attack it at the weekend.

Thanks all for the replies/advice/suggestions