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Metric transposing gears on early Heavy 10

Roger Best

Plastic
Joined
Dec 31, 2020
Hi Folks
Thank you for having me.

I am the proud owner of a 1942 Heavy 10. This machine came over to the UK during WW2 and was almost certainly used at Chatham Dockyard as the owner from which my brother bought it lived in Chatham, as my brother does to this day. Following the deaths of our Father and Grandfather we had a big sort out and this lathe came to me.

It has been cared for, acquiring a unique paint scheme in the process, but had to live in my shed for a decade until I finished my brick-built workshop, so there is some de-rusting to do on parts that where not readily oiled when I wrapped it up and the electrics are in a poor state, they might possibly be original.

The only issue with this well-equipped machine is that it doesn't do metric threads. It has the diagram on the cover but the transposing gears and banjo have gone missing somewhere in its history. Metric threads are the common standard in engineering and its difficult to avoid them totally, although a good die holder works wonders.

Has anyone got a good photo of the set-up, or even a few drawings? This is an early machine like Peter's, with the single lower lever on the gearbox.
https://www.practicalmachinist.com/vb/south-bend-lathes/south-bend-heavy-10-uk-restoration-356686/

I have tried following the links on South Bend's website to Grizley but I don't see anything like this listed.

many thanks for any help and advise you can offer.
Cheers
Rog
Photos to come
 
Here goes with photos.
 

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Roger -

Allan beat me to it. Here is a copy of the original parts list that came with my 1945 machine as far as the metric part goes. Mine was a US machine but had all the pieces shown except the metric gearbox when shipped from the factory. When I got the machine the only part still with it was the metric gearing cover and associated mounting hardware.


Dale

Hv 10 Metric.jpg
 
Roger- Your chances of finding the correct missing parts is very, very low. But, we can likely come up with an alternative. We'll definitely need a catalog of the parts you do have, and some photos.

Here's a list of what you did have: 10L Single tumbler metric - what is in the transposing kit?

allan

Thanks Alan, there's a series of great links here that lead to a photo, where is the list?
I think that Pete and myself have resigned ourselves to making the parts, but you need a lot of data to do that properly.
 
Here's a picture of all the parts in the single tumbler transposing set:

attachment.php
 
Roger I can make any of the gears, except the 127/100, on my hobber. Those two are too large but I was going to make 47/37 for my lathe anyway because the error is so low that it's less than the likely error on the 70 yr old leadscrew.

I have a y-shaped banjo but not the right one. I think mine of from ither a larger South Bend or perhaps a Boxford lathe. It would work except it does not have a crank in it so It'll never line up with the stud gear.
 
Roger, you likely don't have to find (or make) everything that was in the SB set in order to make serviceable metric threads. You might be able to get away with just a simple gear change.
 
Hi guys, happy new year.

Thanks for all the information.
I am sure that there is a good gear ratio that allows the gearbox to produce several pitches, this chap seems to have done it, see 17:45 for the clearest picture:
Metric Threading on an Imperial Lathe - YouTube
However his lathe has several differences to ours, so if anyone has any comments on that it would be much appreciated.

Secondly there are some printed gears available, but they are 80/63, and again the illustration is different to my lathe. Any comments on those?

SOUTH BEND HEAVY 10 METAL LATHE METRIC TRANSPOSING CHANGE GEAR SET 3D Printed | eBay
SOUTH BEND HEAVY 10 METAL LATHE METRIC TRANSPOSING CHANGE GEAR SET 3D Printed | eBay
 
Hi again

just to keep us on a positive note I also have a good selection of Drummond gears, I need to clean them up and count the teeth but its possible I have some of the ratios I need. I also have a milling machine to make anything I can't get economically, so I am sure I can get there eventually.

Peters's gear hobber sounds very useful. :D
CIMG9196.jpg
 
80/63 is closer than 47/37 and might be a better option. I'm just doing mine now based on a South Bend 9" quadrant/banjo. I've milled it down and made an adapter collar. Now just working out the gearing options. It should all fit under the standard cover, hopefully (not that it makes a difference to Roger he has the larger cover already).

I'll update when I have some results.

BTW Roger if you aren't planning on turning BA threads and only plan to cut common fastener pitches you can get away with a very few stud gear options.
 
Hi guys, happy new year.

Thanks for all the information.
I am sure that there is a good gear ratio that allows the gearbox to produce several pitches, this chap seems to have done it, see 17:45 for the clearest picture:
Metric Threading on an Imperial Lathe - YouTube

Yes, that chap got his info from my post here: Cutting a 2 mm pitch on an imperial lathe -

The Home Shop Machinist & Machinist's Workshop Magazine's BBS


Unfortunately, the single tumbler machines don't have as many options, because we can only change the stud gear easily. Let me see what options we have...

allan
 
OK So I've taken (what I bought as) a standard SB9 quadrant and milled the hub down to .965", and milled a notch in the end to clear the tumbler gear. I also turned a sleeve to reduce the bore to fit the 10L

SB10L metric quadrant (1).jpg

I also turned a new shaft for the tumbler, about .600 longer to allow for another outboard gear.

SB10L metric quadrant (2).jpg

This allows the use of the SB9 quadrant which doesn't have a crank like the SB10 one.

SB10L metric quadrant (4).jpg

SB10L metric quadrant (5).jpg

The gears will still fit under the cover, except for the 48 and 60 tooth ones unless you stand the cover off an extra half-inch, but more on that later.

SB10L metric quadrant (3).jpg

I'm working on the best arrangement for the remainder of the gears.
 
Hmm, that setup will make it difficult to use a compound gear on the banjo. I wonder if you could slide the gearbox to the right, maybe by drilling new holes in the top of the gearbox, and turning the threads off the right end of the leadscrew.

Another option would be a double width gear on the lower fork of the banjo.

allan
 
Just a poke of me head in to let you know that after some discussion with SouthBend Ted ( Latheman2 ) and after putting it off for a few years, we are finally making the Transposing Gears right now for the SouthBend lathes so that people can source a high quality compound Metric Transposing Gear and then purchase and modify the commodity gears available at the bargain prices they're often available for. Details will be on the website within the week. Happy New Year.
 
That's great news Zahnrad, I am sure steel is better than 3D printed, although this one looks promising:

100/127T Boxford lathe conversion gear | eBay
He also does a set of gears for £70, pretty cheap, almost disposable.

The method of mounting is pretty important. I am watching Peter's progress closely.
Here is another chap who manages with just a few gears, thanks for the link that led to it:
Metric transposing gear for single tumbler heavy 10

To answer Peters question, I may well want to use BA threads, they are useful for small linkages, you never know what will turn up in the next 30 years, or what a subsequent owner might do in the next 130 years.
 
Hmm, that setup will make it difficult to use a compound gear on the banjo. I wonder if you could slide the gearbox to the right, maybe by drilling new holes in the top of the gearbox, and turning the threads off the right end of the leadscrew.

Another option would be a double width gear on the lower fork of the banjo.

allan


I checked for that. The compound gear stays inside the line of the sliding gear when it's pulled right out, so I think it'll be fine.

at the end of the day I'm using up bits I already have here.
 








 
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