Headstock spindle (Turnstyler Slide Bed Lathe)

[RLSK]

Hi,
I own a Turnstyler Slide Bed Lathe and it has an unusual headstock spindle, it has no thread and has a hole right through the headstock to accommodate a threaded bar which can be attached to faceplates and a Oneway Stronghold chuck which has been modified in someway.
I have this idea that I could have a threaded spindle made which could fit onto the existing headstock spindle, it would need to be approx 100mm diameter with a circular recess with locating pin and threaded hole to take the threaded bar and obviously the threaded spindle that will hold modern chucks, etc.
My question is, what would be the best thread to use? How long should the threaded part be? Length of register beyond the thread?, etc.
I have tried to find these details on some larger lathes out there but can't find anything.
Kind regards
Rob

[fuzzyturns]

I personally would go for a M33 thread, as most new kit will be made to fit onto that (or at least have an option for this). I believe the M33 mounting is actually standardized, and you should be able to dig up some spec on the internet. If not, let me know and I'd be happy to provide you with a diagram showing all relevant dimensions from my own lathe.

[RLSK]

Thanks fuzzyturns
Yes I was thinking m33 but I spent a few hours yesterday trying to find all the dimensions I would need to give to someone for making it also what type of metal should be used?
Kind regards
Rob

[fuzzyturns]

I can get you the dimensions of my headstock this evening. Since this is not an engineering lathe, you don't need any specialist steel, standard tool steel should be fine. If you can afford the cost of stainless steel, that's better, but it will also take longer to machine (it's tough stuff).
I can't easily identify a suitable source for an official standard right now either, so the drawing from my lathe is the best I can do.

[The Bowler Hatted Turner]

Not sure if stainless steel would be the material to use. It has a tendancy to bind on the threads.

[RLSK]

Thanks fuzzyturns
That would be most helpful but only when you have time.
Kind regards
Rob

[Twisted Trees]

From my Axminster 1628

Shoulder 55mm diameter 10mm thick

Chuck mount shaft 30mm long

Plain un-threaded  section 33.9mm diameter 5.5mm long

Shoulder for reversing grub screws 28mm diamater 6.2mm long

Thread section

M33 32.6mm diameter 4mm thread pitch 22.2mm long

[Docjohn]

Hi Rob
I too have a slidebed, when I ordered it Fred asked what chuck I was going to be using, then made a "flange" on the end of a spindle the chuck could be bolted on without the backplate. This enabled it to be used in forward and reveres with no fear of any unwinding, plus it reduced the overhang.
I had previously used a Myford ML8 so Fred made me a 2MT carrier and a spindle for a few bits I already had
Hope the pictures help
John

[RLSK]

Thanks to Twisted Trees for that information and to Docjohn for the photos from your Turnstyler lathe, i also have a no 2 morse taper carrier. Not quite grasping the spindle you had made by Fred. Is it the one pictured alongside the mt carrier and is it held in the headstock just using the grub screw. I was thinking it would need to incorporate the threaded bar that passes through the headstock.
Kind regards
Rob

[Docjohn]

I think each of his lathes were a bit different as the “evolved “ plus the chucking type that was specified
Mine has a shoulder inside the headstock spindle so the carrier/threaded spindle can’t go in too far (yes the one in the picture) it’s a snug fit so pulling it out I sometimes needed to tap it from the pulley end. The grub screw was just there to prevent any rotation and prevent the threaded spindle creeping forwards in use
I hope I’ve explained this well enough
John

[RLSK]

Hi John,
Yes, sounds like mine. I have faceplates that have a recess with a locating pin
in the back of them to accommodate the headstock mounting. These all attach to the threaded bar that passes through the headstock. So am I right in thinking that I could have a threaded spindle made that will just fit in the recess (25mm approx) that will be locked with the grub screw? Just would have thought there could be a chance of it spinning loose, that's why I thought of utilising the locating pin and threaded bar for mounting. Obviously I have the large chuck that fastens to the threaded bar for large projects but need to have option for smaller chucks, etc. Apologies for going on
Kind regards
Rob

[Docjohn]

Hi Rob
No problem
I never had a problem with the grub screw but I have to admit I rarely use it now as the only thing I tend to use it for now is an old 3 jaw chuck, otherwise I have a morse carrier for my chuck now that saves time
I hope you get it sorted
Regards
John

[Maca]

Not sure if stainless steel would be the material to use. It has a tendancy to bind on the threads.

It's called galling.  When you have two pieces of material sliding over each other and the surfaces stick.  It is a common problem with threaded components of the same hardness and stainless steel is prone to it.  So if you make your spindle out of stainless steel and you have SS faceplates, adaptors, chucks etc. then you may encounter galling. 

[Maca]

Thanks fuzzyturns
Yes I was thinking m33 but I spent a few hours yesterday trying to find all the dimensions I would need to give to someone for making it also what type of metal should be used?
Kind regards
Rob

M33 is a metric thread size which is defined, starting on page 1783 of Machinery's Handbook 28th Ed.  or other similar engineering reference book.  Any machine shop will be familiar with it and you don't need to define the dimensions, you can simply call out the thread on the drawing.

[Sandy]

Hi Maca,

But RLSK would still need define what he needs for the mating parts he'll screw on to the shaft (if I understand his query correctly)
 

How long should the threaded part be? Length of register beyond the thread?,