Headstock Spindle Thread

[tony]

I have a Nova DVR 3000 which was purchased new in 2003. I bought this second hand from a club member, who has sadly passed away. There is some minor thread damage & I wondered what the best course of action would be. I may be wrong , but I think it's M33 x 3.5 RH. Thanks in advance. Cheers Tony.

 

[NickDReed]

Hi Tony,

Looks like you would be able to replace the part if it has come to that.

https://www.carbatec.com.au/documen...nODPYYAi3NBi2dU6Cy0Kj_FkqnDXhz4JctUeQOiYJ8EZs

55003 Headstock Spindle 1 1/4" 8 UNS RH
55103 Headstock Spindle M33x3.5 RH

It appears the lathe has been discontinued, but https://www.teknatool.com/contact-us/ might be a good place to start to see if you can get parts in the UK.

 

[ChaiLatte]

The manual gives you three choices of thread size:

https://www.carbatec.com.au/documents/manuals/Nova/nova-dvr-3000-manual_mar-2005.pdf

If you are unable to discern the thread pitch using a ruler or calipers (measuring over as many threads as possible), you can buy a thread pitch gauge for £6.29 (https://www.amazon.co.uk/Stainless-Thread-Imperial-Cutting-Measuring/dp/B08MT6KYVW) which will assist in that determination.

Posting a photo of the spindle would help us to give specific advice on solutions to your problem.

If the damage is minor and the thread is metric, a small triangular file can dress the threads better. At larger expense, a thread restorer file is better, but I am unable to locate one which offers 3.5mm pitch.

 

[Duncan A]

If, as you say, the damage is minor, I'd just try dressing the threads with a small triangular or thin file, or even with a set of needle files.
Possibly even a suitably shaped diamond sharpening tool which you could then use for little tool sharpening jobs around the workshop.

 

[SVB]

You can buy m33 x 3.5 dies for not much (or if you’re near Glos you can borrow mine!).

 

[Paul Hannaby]

Aren't those lathes 1 1/4" x 8tpi? That may explain the thread damage!

 

[Inspector]

Aren't those lathes 1 1/4" x 8tpi? That may explain the thread damage!

The ones sold here in North America were. Both my Nova 3000s are. Can't say what would have been sold around you.

Pete

 

[Phil Pascoe]

Two different backplates listed -
https://www.beaufortink.co.uk/toolp...readed-backplates-for-versachuck-lathe-chucks

 

[tony]

Aren't those lathes 1 1/4" x 8tpi? That may explain the thread damage!

I've just had a look at the lathe & you are correct , it is 1 1/4 × 8tpi. I don't know if the insert is the correct size as it came with the chuck. There doesn't appear to be any damage to the internal threads on the insert , but there is some damage to the spindle threads on the lathe.

 

[tony]

If, as you say, the damage is minor, I'd just try dressing the threads with a small triangular or thin file, or even with a set of needle files.
Possibly even a suitably shaped diamond sharpening tool which you could then use for little tool sharpening jobs around the workshop.

I did try filing it with a small triangular file, but it hasn't solved the problem.

 

[tony]

There is what looks like an L imprinted on the insert. Does this suggest that it's L/H or something else.

 

[ChaiLatte]

There is what looks like an L imprinted on the insert. Does this suggest that it's L/H or something else.

A left hand thread item would generally be used on an outboard spindle.

Have a look around at the various suppliers of inserts for the chuck. If no-one at all makes a left hand insert of the specific diameter and pitch that you have, yours is unlikely to be the only one in the world.

You can poke a softwood stick into the insert (as big as will fit), tap it sideways with a mallet so the threads imprint into it. Pull it out and look at it compared to a known RH male thread. If the imprints slope in the same direction, it is RH.

Take a photo of your spindle so we can advise on the damage.

 

[Inspector]

A left hand thread item would generally be used on an outboard spindle.

Have a look around at the various suppliers of inserts for the chuck. If no-one at all makes a left hand insert of the specific diameter and pitch that you have, yours is unlikely to be the only one in the world.

You can poke a softwood stick into the insert (as big as will fit), tap it sideways with a mallet so the threads imprint into it. Pull it out and look at it compared to a known RH male thread. If the imprints slope in the same direction, it is RH.

Take a photo of your spindle so we can advise on the damage.

The Nova lathes do not have provisions for outboard turning, the headstock swivels. The shaft is more or less flush on the outboard end of the headstock and has an internal thread for a small hand wheel (if mounted) that also serves as a connection for vacuum chucking. I can stick my index finger in just past the finger nail. My highly precise measuring tool for holes.

Pete

 

[Paul Hannaby]

Is the problem here that you are trying to put an M33 chuck/insert on to a 1 1/4" x 8tpi spindle thread?

 

[ChaiLatte]

The Nova lathes do not have provisions for outboard turning, the headstock swivels.

What relevance does the model of lathe have to the question asked by the OP?

He has a chuck, with a threaded insert in it, that possibly might be left hand thread (see post #11).