Stuck collet on head - how to budge

[elver]

Hello again,

My new 21 year old Nova has a Vicmarc chuck collet stuck on the head. (It’s M30 so I’m pretty sure it’s a collet)

I tried to get it off today to put on a nova scroll chuck but I can’t make it budge. Normally I’d next apply some heat to try and break the rust / stiction.

Looking at the deflected holes for the wee tommy bar used to move it, I think it’s been stuck a while.

https://uploads.tapatalk-cdn.com/20200629/aaab939a1c59f636dca36e0935ee79eb.jpg

https://uploads.tapatalk-cdn.com/20200629/aaec940761e5530b7efbab3627a271b3.jpg
Is this the right approach?
Is there anything that could be damaged by heating it up or is there a better way?
And is turning towards the viewer in the bottom
Image the correct way to remove it?

Thanks!


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[Bohdan]

Get the correct C spanner (https://www.ebay.com.au/i/233534383051?chn=ps&norover=1&mkevt=1&mkrid=705-139619-5960-0&mkcid=2&itemid=233534383051&targetid=896057791431&device=c&mktype=pla&googleloc=1000567&poi=&campaignid=9772799703&mkgroupid=100117146376&rlsatarget=pla-896057791431&abcId=578876&merchantid=115489191&gclid=Cj0KCQjwoub3BRC6ARIsABGhnyb7hUe4fXMY8rIdPHaTUZyXHGsDTonL2ChQtxaqv_2CWe1IPUxV8HQaAsxxEALw_wcB) and then give the spanner a sharp hit with a hammer. That should shock it loose without having to resort to heat.

[elver]

Ah, c spanner, that’s an idea!
Now to work out what the correct size is..


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[Treecycle]

Turning the top towards you is the correct direction to undo it.
Get a mild steel bolt that fits neatly on the hole when the tread is cut off. Put the bolt in one of the holes, get a short length of hardwood and hammer. Engage the spindle lock and put the wood against the bolt close to the adaptor. Push the wood firmly against the bolt in the direction to undo it and then strike the wood with the hammer with short sharp blows and it may release the thread. Don't get carried away with the hits that you start bending the bolt as you could start to damage other parts. I don't know how substantial the locking pin is so this may not even be a good idea, but if it's fairly robust and well supported you should be alright. Like I say, don't get carried away with the hits. If it doesn't release quickly don't persist.

[P.W.H.]

Can't you put a drift through from the back and knock it out? I assume it's a morse taper?!?

[malb]

From the pics, you are dealing with a thread adaptor (internal female thread to fit onto spindle thread, and a male external thread to install a threaded device with a different thread diameter/pitch). If this is so, a drift inside the spindle won't help.

A collet woul fit inside the spindle bore and close down onto your work to grip, either with a collet nut screwing onto the spindle thread, or with a drawbar throw the spindle bore and a handwheel or similar at the back of the spindle. Very common for metalworking lathes, less so for woodworking lathes.

I assume you have had the chuck installed previously so know that the spindle and chuck have compatible threads. If not, it is possible that the lathe and chuck have mismatched threads and what you have pictured is the spindle thread, with a C spanner/tommy bar hole to facilitate removing other threaded accessories. (Not familiar with your machine).

[elver]

Looking at the manual this is indeed a thread adaptor changing the thread from 20mm teknatool to m30 for the vicmarc chuck.

C spanner and tommy bar approach will be attempted when I can find the correct sized c spanner.


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[Paul39]

My approach has been to soak threads liberally front and back with penetrating oil, PB Blaster, WD-40, or your favorite mouse milk. With a small hammer, preferably brass, turn the spindle and tap, tap, tap, around and around, adding penetrating oil as you go. Soak liberally and let set overnight.

Next day oil up again put tommy bar or cut off bolt in hole facing up. Immobilize the spindle by winding clothesline or whatever rope handy tightly between handwheel and headstock. Put a piece of tape around spindle nose ahead of the stuck adapter and mark adapter and tape. With a steel rod as opposed to a piece of hardwood, place against the tommy bar or bolt and give it 2 - 3 good sharp whacks with a 16ish ounce hammer. Check to see if you have movement. If any movement, oil up and keep driving. If you have gotten a stout C spanner use that. I like to whack a spanner with a 1/2 inch steel rod.

Thinking behind: Clothesline instead of locking pin, lots of force may be involved, pin may be broken off or pulley split. Steel rod instead of hardwood, transmits shock better than wood. Fast whack instead of heavy dead blow hammer, again sudden shock.

If the above fails, another round of oil, tapping, & overnight soak, then as above. That failing, ice in Morse taper, heat on adapter from propane torch, oil, whack.

When you get the adapter off, oil up male & female threads and run the adapter on and off several times, wipe off or use a tooth brush to get off rust and crud. Oil up and rotate your Morse taper bits in the head and tail stock and wipe off once or twice a year. That keeps things from getting stuck.

Some years ago I bought a 20 inch swing short bed Woodfast, hand wheel, face plate, tail center, were all rusted in place. Over two days of persuasion all came loose.

[elver]

Sooo.. after lots of soaking with penetrating lube and all the above suggestions this thing is still stuck. Even heat didn't budge it.

Given it fits into the back of a vicmarc chuck and I have an operational vicmarc 140 and all its bis, I plan to just work around it.

I'll keep lubricating the internal thread but I think its a permanent fixture for now.

[BobL]

How are you holding the other end of the headstock spindle?

If you have enough access sometimes it is easier to fix the headstock adapter with a C-spanner and instead turn the headstock with a snake/strap wrench.

If you can eventually get it off, to make it easier to get off next time is to clean the thread up as much s you can and paint it with anti-seize - a cheap form of anti-seize is a copper sulphate solution which deposits a thin layer of copper onto the thread.

[elver]

Hi Bob, the other side has nothing. Just a female thread inside the headstock.
So I'm just holding the head with the locking pin.

Its not budged yet.. still adding lube daily.

I'm starting to think my lathe now has a 45mm diameter spindle (from the vicmarc insert) for good.

[LanceC]

Is there any chance a previous owner used Loctite on it? Perhaps heat is your best bet at this juncture.

[elver]

I heated it over the weekend - hot enough to bubble out boiling WD40 from the cracks, and still no movement. I'm thinking maybe it was forced onto a deformed thread maybe.

[Acco]

Are you using a c type scanner, if so give it a belt with a hammer or block of heavy wood, it needs a shock load applied to loosen it

[Pagie]

Get a bigger hammer.