EW Stringer Lathe Spindle Speed

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EW Stringer Lathe Spindle Speed

This topic has 9 replies, 7 voices, and was last updated 2 July 2024 at 23:52 by Paul Lousick.

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24 June 2024 at 07:48 #737433
James Alford
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@jamesalford67616
The EW lathe that I recently acquired has a steel spindle running in cast iron. Am I right in thinking that this arrangement can handle a top spindle speed of about 1,000rpm? I need to find a motor for it and sort out the drive arrangement.

Regards,

James.
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24 June 2024 at 10:41 #737448
SillyOldDuffer
Moderator
@sillyoldduffer
lathes.co.uk say much slower than 1000rpm!

Speeds direct r.p.m.: 606, 303, 151

These come from belts driven by an 1425 rpm motor

Motor belt ratio: 1.5/7 = 1/4.7
Final belt ratios: 2 : 1, 1 : 1 and 0.5 : 1

Dave
24 June 2024 at 11:23 #737457
Hopper
Participant
@hopper
Then again, the original EW Stringer sales brochure HERE gives a lot of specs, including a 400 RPM recommendation for the countershaft. Which would give 800 RPM for the headstock spindle, using the 4″ and 2″ pulleys for top speed.

That was fairly typical top speed for plain-bearing lathes of the era. But I ran my Drummond M-type bumped up to 1,000rpm top speed for a good few years with no ill effects. So you could probably get away with that.

The sales brochure also gives the spindle thread as 1″ x 12 TPI, which you asked about before. It would be Whitworth thread form, being British made. Same thread as a Drummond M-type. But I think the Drummond’s chucks would be too large a diameter for the EW. And maybe some difference in the unthreaded locating register collar on the spindle.
24 June 2024 at 12:56 #737473
jim1956
Participant
@jim1956
>The sales brochure also gives the spindle thread as 1″ x 12 TPI, which you asked about before. It would be Whitworth thread form, being British made. Same thread as a Drummond M-type.

Just a heads up that post-war vintage British lathes might not be Whitworth.

I have an old unbranded lathe of the Randa/BSW or possibly Winchester Model H type.

All BSF threads in rest of the fasteners but the spindle thread is definitely 1″ x 12 UNF.

Confused me for while because I was buying an ML8 faceplate from ebay and a 1″x 12 backplate from RDG which I struggled to fit and required a lot of thread scraping. Then I tried a UNF 1″ x 12 nut, screwed on without a problem. The threads on the spindle are definitely 60 degrees rather than the Whitworth 55 degrees.

I can’t imagine that anyone would go to the trouble of re-cutting the spindle nose on such a cheap lathe, perhaps spindles were a bought in item from the USA in the 1950s.

Jim
24 June 2024 at 13:42 #737481
Hopper
Participant
@hopper
Jim: That’s interesting. Hard to imagine importing spindles in austerity-riven 1950s UK would be economical for a budget lathe maker. But who knows?

On the other hand, 1″ x 12tpi is a standard UNF thread, so taps and dies would have been available (Yankee war surplus?) whereas standard 1″ BSF is 10tpi so its taps and dies could not be used if they wanted the finer 12tpi thread that seemed more commonly used on lathe spindles in those days.

I notice in the pics on Lathes.co that the EW works had exclusively American SouthBend lathes equipping their “works”. Maybe they were a bit partial to US machinery, maybe also other war surplus tooling?

Another of life’s little mysteries!
25 June 2024 at 07:47 #737597
James Alford
Participant
@jamesalford67616
Thank you for all of the replies and information.

It is good to know that whilst the top speed of the lathe was around 600rpm when supplied, the type of construction can handle 1,000rpm or so. My Flexispeed is about 450rpm, so something a little quicker would be useful. I just need to sort out a motor and some pulleys.

Thank you, also, for the information about the thread on the spindle. I shall probably want to make a faceplate for the machine, so this will be good to know.

Regards,

James.
25 June 2024 at 07:57 #737598
John Haine
Participant
@johnhaine32865
On 24 June 2024 at 13:42

…

I notice in the pics on Lathes.co that the EW works had exclusively American SouthBend lathes equipping their “works”. Maybe they were a bit partial to US machinery, maybe also other war surplus tooling?

Another of life’s little mysteries!

There were hundreds or maybe thousands of imported Southbend lathes surplus after the war so not surprising. A friend’s father was setting up a mining machinery company and needed a few lorries so he bought some surplus, only to find they hadn’t bothered to unload the surplus lathes from them!
25 June 2024 at 14:17 #737752
Martin of Wick
Participant
@martinofwick
If you google around ‘safe speed cast iron bearings’ or something along those lines, you will find the notional max surface speed, which you can convert to RPMs for the spindle size on the EW. When I did this a few months ago, I think it came out at about 650 (I think it was in a thread on EW lubrication – I would try to find but it is too much of a palaver to locate historical posts now)

You may want to check the existing bearing for wear, movement, ovality etc. before deciding to run at higher speeds as you could make matters worse. Probably ok to run at higher speed for a short burst, but not as the default speed for extended sessions.
2 July 2024 at 23:09 #739108
James Alford
Participant
@jamesalford67616
Following on from my spindle thread question, would anyone with a Myford ML8 mind measuring the register OD, please? I am wondering whether a ML8 faceplate will fit the EW lathe.

Thank you.

James.
2 July 2024 at 23:52 #739118
Paul Lousick
Participant
@paullousick59116
I have a 9″ Southbend lathe which is similar to the Hercus in Australia and Boxford in the UK which runs in cast iron bushes. The manual states a top spindle speed of 1270 rpm. I don’t run it that fast as it is 60+ years old and keep it well lubricated.
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