Pultra 1590 bearings

[Jon HolmesParticipant @jonholmes92873]

[Jon HolmesParticipant @jonholmes92873]

I have the headstock of my recently purchased Pultra 1590 apart. An initial inspection revealed a fair amount of very sticky black remnants of previous lubrication – enough to decide to pull apart to clean properly.

The two bronze main bearings have 6 slots on the outside. One of these has laminated shims for adjustments, The other 5 of mine could be felt wicks – but at the moment they are quite solid and black. Does anyone know the make up of the material in these slots?

Thanks, Jon

[Ady1Participant @ady1]

If you're going to take a 1590 to bits I would get a manual

I would also take lots of photos, this is a very rare event in lathe world

…the belt could be changed on all versions without having to disturb the setting of the super-precision plain headstock bearings…

**LINK**

GL

[Jon HolmesParticipant @jonholmes92873]

I do have a 30 page Pultra publication that does detail the adjustment and dis-assembly/re- assembly of the headstock. Are there any others?

I have also decided the material in the 5 slots is not saturated and hardened felt – it seems some sort of plastic (?).

Edited By Jon Holmes on 17/10/2017 12:02:02

[Ady1Participant @ady1]

it seems some sort of plastic (?).

I pulled a bit of Lignum Vitae from my cross slide years ago (I too thought it was plastic but asked in here), it's a wood that sinks in water and has amazing wear resistance properties

Your headstock rebuild is well worth documenting because it may be the only one on the entire internet

Edited By Ady1 on 17/10/2017 15:05:51

[Jon HolmesParticipant @jonholmes92873]

Once the bearings were cleaned, the grain of timber was obvious. An interesting choice of material, considering it is in a fairly stationary location (non rotating).

The close up image of the bearing shows the dark timber, and below it a slightly narrower shim.

[Jon HolmesParticipant @jonholmes92873]

The spindle is 300mm long, the diameter at the plain bearings is about 45mm. The image shows the spindle complete with all bearings, spacers etc. It weighs approx 6kg – it is quite substantial for a small lathe!

[Viraf EduljiParticipant @virafedulji62170]

I am trying to restore a Pultra 1590 and am totally new to this. Cant seem to get the headstock off. Can you please guide me?

[Ady1Participant @ady1]

If you're new to this game then a 1590 is the last thing you should be pulling apart

At the very least, Get a manual

[Jon HolmesParticipant @jonholmes92873]

Viraf, low on the back of the headstock are two bolts (#40) that tighten/loosen #38 via a cam system.

[david bennett 8Participant @davidbennett8]

The slots do contain some kind of plastic/ Paxolin? I believe its to allow a limited flexibility to the bearings when shims are adjusted.

Edited By david bennett 8 on 26/05/2021 14:38:43

Edited By david bennett 8 on 26/05/2021 14:44:36

[Jon HolmesParticipant @jonholmes92873]

Definitely timber in the slots. The slots in the bearings themselves would allow some movement. Not sure the purpose of the wood infill (maybe to quieten any possible resonance from the slotted bearing?)

[Viraf EduljiParticipant @virafedulji62170]

Was told on another forum on fb that this is not a 1590, but a 17 series, can anyone please confirm? Am adding some more photos as reference.

[Roderick JenkinsParticipant @roderickjenkins93242]

The bed on a 1700 series lathe is 18" (46cm), a 1590 is twice that. The countershaft looks much heavier than a 1700. See ADY1's link above

Rod

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Viraf Edulji on 29/05/2021 14:13:11:

Was told on another forum on fb that this is not a 1590, but a 17 series, can anyone please confirm? Am adding some more photos as reference.

.

Get your measuring-stick at the ready … and look here: **LINK**

http://www.lathes.co.uk/pultra/page9.html

You will find a couple of comparison shots near the bottom of the page

MichaelG.

.

Rod posted whilst I was finding the link.

Edited By Michael Gilligan on 29/05/2021 14:34:52

[Ady1Participant @ady1]

You have no slot along the back for the Thread Chasing attachment

Mine is the same, it was for making missiles in the 60s at english electric and must have been made deliberately to not have that option to save money

Edited By Ady1 on 29/05/2021 19:29:37

[Viraf EduljiParticipant @virafedulji62170]

If you notice, in my first photograph, there is an attachment behind the headstock with a holed disc and a locator pin. Any idea what this is for?

[Viraf EduljiParticipant @virafedulji62170]

If you notice, in my first photograph, there is an attachment behind the headstock with a holed disc and a locator pin. Any idea what this is for?

Also on the headstock spindle is a wide knurled ring with just about a quarter turn of travel, it kind of locks up the spindle when rotated in one direction. Any idea what purpose does it serve? Am adding photographs of the item.

[Jon HolmesParticipant @jonholmes92873]

My close up photo of a 1590 bearing (from early in this thread) shows it having a thread at both ends, with a steel adjusting nut on each thread. These nuts are adjusted to move the bearing in/out of the headstock taper which tightens/loosens the bearing/spindle clearance. You seem to be missing the outside front nut?

[Jon HolmesParticipant @jonholmes92873]

What is the inside diameter of the spindle? A 1590 would usually be 20mm, a 17 series 8 or 10mm.

[david bennett 8Participant @davidbennett8]

Posted by Jon Holmes on 27/05/2021 00:20:59:

Definitely timber in the slots. The slots in the bearings themselves would allow some movement. Not sure the purpose of the wood infill (maybe to quieten any possible resonance from the slotted bearing?)

Just for the record, I checked some spare 1750/70 bearings. They also have timber inserts.

[DellParticipant @dell]

A manual for the 15/90 17/50 ana 17/70 are still available from Smart & Brown at this link https://www.smartandbrownlathes.com/

I have just ordered one for the what I thought was a 17/50 but when it arrived I found it was a 17/70 .

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