Smart and Brown Sabel

[Philip PowellParticipant @philippowell34749]

Hello, I’m new to this site and also the new owner of a lovley old Smart and Brown Sabel lathe. I was going to buy a Chineese lathe but the supplier was messing me about and most companys were out of stock the model was after. Any how this Sabel came up for sale and it now resides in my workshop. I understand the lathe is another Southbend copy but it’s very well made.

At present I’m repainting the base and cleaning down the machine ready for use.

I do have a couple problems to sort out though; the bed is showing some signs of wear and could do with a regrind, later maybe. More of a problem is a broken backgear tooth

By the way although this is the first lathe I have owned I have used many in the past, long way back in the past. Hopefully it will all come back to me when we start turning….

 

Phil.

 

 

[Philip PowellParticipant @philippowell34749]

[Richard ParsonsParticipant @richardparsons61721]

What is the back gear wheels made of? There is an old clock maker’s trick which allows you to rebuild or make a new tooth.

[Philip PowellParticipant @philippowell34749]

Richard, thank you for your reply. I think it’s made of steel. If it’s repaired rather tahn replaced it will need to be a very strong repair as it’s part of the drivetrain when in backgear.

 

Phil.

[Chris BParticipant @chrisb73862]

Philip

 

As it is a Southbend/Boxford clone, you could try John Ward at http://www.latheparts.co.uk as he makes spares for Boxfords.

 

Hope this is of use

 

Chris

[Philip PowellParticipant @philippowell34749]

Thank you Chris I will give John Ward at Latheparts a try.

 

Phil.

[david newman 9Participant @davidnewman9]

I had a Sabel many years ago not a bad lathe, bit of useless imformation SABEL stood for

Smart And Brown Enngineering Limited. David

[adyParticipant @ady]

Dang. That’s a nice looking bit of gear.

 

Once you get some skills you could fix it yourself, or lathes.co.uk might help.

 

 

Although spares are no longer
available for this range of S & B lathes, most Boxford and South
Bend parts and accessories will fit (including the T-slotted cross
slide) so providing a cheap and easily route to restoration. These, and
one-off parts can be obtained from lathes.co.uk For more details of the original South Bend model click here

 

http://www.lathes.co.uk/smartbrown/page5.html

[Dinosaur EngineerParticipant @dinosaurengineer]

“gandmtools” have quite a stock of Boxford parts . Do a search on Google you’ll soon find it.

[Philip PowellParticipant @philippowell34749]

Thanks again for your replies, much appreciated. I’ve contacted Tony at lathe.co.uk and he maybe able to help. His websited was a mine of information when I purchased my Sabel, I found my lathe on his site.

I will contact G an M tools, they do list some Smart and Brown spares, not what I’m looking for though, I will still contact them as some stuff may not be listed.

 

Thanks

 

Phil.

[Richard ParsonsParticipant @richardparsons61721]

OK if the wheel is made of steel. That is good as it means that if you can find a good skilled welder get him to rebuild the tooth making sure the rebuild is ‘chunky’, if necessary almost fill the gap left by the broken tooth. I would then skim the wheel in the lathe to clean it up. Next make up a template by clamping a piece of bright mild steel coated with marking blue (or copper sulphate dissolved in vinegar). Clamp it to the wheel and with a sharp scribe follow closely the teeth. Now saw and file up the profiles.

If your gear wheel is hardened an alternative is to copy the teeth as ‘positives’ by clamping two thin scraps of gauge plate and filling up exact copies of the teeth. As I approach the thing I am copying a use finer and finer files. When finished harden the gauge plates and use them as filing guides.

As a young lad I have done this sort of thing, many times in a pair of waders refitting wooden teeth to the great wheels at t’mills.

[Philip PowellParticipant @philippowell34749]

Richard,. Thank you for taking the time that is a great description how to repair a gear. Before I start mucking around with the existing gear I want to try and find a spare as I can still use the lathe at present but I cannot use the backgear. Also the gear is machined out of the same piece of steel as the drive pulleys, no pulleys, no lathe.

 

There can’t be many folks around these days who can repair a wooden gear. Good health to you.

 

Phil.

[Richard ParsonsParticipant @richardparsons61721]

 

Ah! you did not say it was the small headstock wheel that was the problem. Can you tell us more about this wheel? What is its DP (Diameteral Pitch) being a US machine it will probably be Inch standard. Count the number of teeth and measure its diameter divide no of teeth by diameter and round the answer up to the nearest whole number –because you have measured over the ‘Addendum’-. The D.P. will be a whole number. Example suppose the wheel has 40 teeth and measures 2.625 inches then the calculated DP would be 15.24 so round up to the nearest whole number which is 16 and there you are.  Actually you can visti HPC Gears web-site and look ar their on-line catalogue this gives you the Overall Diameter (and the PCD)

Measure (in Millimetres) the distance between a point on a tooth and the same point on the next tooth. This will give you the Module. Have a look at the standard lists of Module gear cutters this will tell you what module it really is. But to be honest I do not think it will be metric.
Once we know this who knows what we can do to help you.

I would have a very close look at the whole assembly. I have a feeling that unless the wheel concerned is larger than the nearest pulley it will have had to be made separately. Can you post a picture of the assembly? Can you tell us also how wide the thing is.

Actually cutting wooden gear teeth by hand is not difficult you just have to have some razor sharp long chisels, one or two nice sharp gouges –for roughing- a good template which spans a few teeth and patience –Dad paid me 6d an hour to do them.- I think he charged 5/- per hour for the job.

 

Edited By Richard Parsons on 08/02/2011 16:42:28

[TerrydParticipant @terryd72465]

Hi Philip,

 

I may be breaking a Boxford lathe soon and the back gear is ok.

 

Please PM me and we can discuss.

 

Terry

Edited By Terryd on 08/02/2011 17:01:50

[Dinosaur EngineerParticipant @dinosaurengineer]

Hi ! Philip,

Anyone with a Smart & Brown lathe ( any model) is strongly advised to become member of the Smart & Brown group on Yahoo Groups . There is a weath of knowledge on this website and members are very helpful with any request for info and help . There are loads of files / photos/ copies of manuals, There is no charge for joining or getting access to all this info.

 

 

[Philip PowellParticipant @philippowell34749]

Richard, I will measure up the gear tomorrow and also post some photo’s.

 

I agree with your comments that you would expect the gear and pulleys to be manufactured as separate components but I cannot see any joins, pins or anything that would hold them together and the parts manual only show one number for gear and pulleys.

 

Terry, PM on it’s way.

 

Dinosaur, Great idea, I will join the Yahoo Smart and Brown group.

 

Many thanks

 

Phil.

[Anonymous]

If you add 2 to the number of teeth before dividing by the OD of a gear, then you get the DP exactly; no need for approximations.

 

Regards,

 

Andrew

[Richard ParsonsParticipant @richardparsons61721]

Andrew – Very useful knowlege. (Teeth count +2)/OD =DP Any rules for Module?

[Keith LongParticipant @keithlong89920]

Richard

(No of teeth +2) X Mod=OD – but work in mm

Keith

[Philip PowellParticipant @philippowell34749]

I’ve uploaded some photo’s of the broken gear to my profile. The groove you can see in the bore is an oil groove, I can’t see any join between between the gear and pulley.

 

The gear has 40 teeth and a dia of 2.619″ (66.54mm)

 

Phil.

[Richard ParsonsParticipant @richardparsons61721]

Philip – Yes it was machined on the common shaft and is integral with the pulleys. It was either cut with a gear ‘shaper’ or by a ‘rack’ planning process, the details do not matter. The gear is i think 16D.P.

Looking at your pictures and thinking about how I would mass produce the thing I am fairly certain that the whole pulley assembly is a casting made in ‘Spherical Cast Iron’. The fracture displays many of the characteristics of a fracture in cast iron. I have seen quite a few of this type of fracture mainly on agricultural machinery. The surface finish also shows a similar type of finish to that found on spherical cast.

From the photos and a bit of (trickery) I think you have only about 3/8” to play with. This will limit your options as cast iron does not like being under tension. That would rule out the ‘Special screw’ or ‘peg’ methods of fixing the problem. If you want to see an example of this visit the Submarine Museum in Gosport where you will see an example of a repair made at the bottom of the ‘great dampness’ to a helical cut bevel gear. By gosh the ‘Tiffies’ must have been good to do that by hand! If you cannot get a spare then I think you have only two options, flog the lathe and let someone else make the repair, or repair it yourself. If you choose the latter case then I am afraid only leaves you with, I think, two alternatives methods which could be used to make a repair, one of which will defiantly need access to a lathe.

This first method is to buy a suitable 16D.P. 40 toothed wheel and machine away its centre.. Then machine away the old damaged gog down to a good ‘shrink fit’. When SWAMBO is not looking heat the gear you have trepanned out to about 200-250°C in the kitchen oven and slip it onto the pulley assembly. When it has cooled, to hold the thing in place, I would drill 3 or 4 say 2BA tapping sized (or similar) holes into the gear and pulley assembly exactly on the join between the two parts, tap them and insert suitable socket heads grub screws with a little thread-lock for added security. These act as both keys and retainers. You will need to check the hole up the middle as you may need to ream it if the added gear wheel has compressed the pulley assembly.

The second method is to have a welder build up a new tooth stub. Then by careful filing, clean everything up. File the new tooth to length and then profile it using a template and fitter’s blue for the final fitting. (You can pinch SWAMBO’s lipstick for this process but it is not as good) and in my experiance causes ructions if you are caught). It will mean refitting the assembly several (or many) times checking the fit with fitter’s blue. Filing or scraping down the high places until the thing runs nicely. Laborious job but very satisfying when completed.

I hope others can find other alternative methods, but part of the problem is that spherical cast contains graphite which precludes the use of modern adhesives and does not braze very well.

Any way Good luck as it looks a nice machine

[Philip PowellParticipant @philippowell34749]

Richard

 

Wow , thanks for your reply, very detailed. I’m reluctant to mess around with the present gear as I can still use the machine although anything needing backgear is out. I going to hang on and see if I can find a spare first, who knows one may turn up. If I can’t find another gear then I will have a try at repairing this one or sell the lathe.

 

Thanks again.

 

Phil.

[adyParticipant @ady]

I redid my backgear with t6 aluminium, but almost half my teeth were missing, the old girl had taken a hammering and needed a total fix.(the piccy is in my profile)

I turned the teeth off the mandrel after measuring everything up then made a t6 copy with an undersized bore then made a quick shallow 8tpi screwcut through the bore for the undersize bore aluminium to “squish” into when I fitted it.

Fitting was a case of battering it on to the mandrel, protected by a hard plastic drift.

The alternatives in my mind were a keyway or a grubscrew which would involve more drilling and messing about on the mandrel and involve uneven stresses on the cog when it was working hard and doing intermittent heavy cuts.

 

The instant difference in the usefulness of the machine is like night and day, especially with tough jobs. The backgear can also be disengaged at the end of a screwcut job and the saddle whirled quickly back by hand to the start of a screwcut while still directly attached to the mandrel via the changewheels, very useful for jobs like metric cuts when you don’t want to disengage the leadscrew nut, then re-engage the backgear cluster(kinda like a lever operated idler cog system) and hog another cut in the thread.

 

With only one tooth missing you’re in a really annoying position but the fix, whatever you do, is well worth the effort.

 

It took me 14 months in my spare time to build the bits like the milling spindle to actually do the job I wanted to do, so be patient, you shall definitely be rewarded if you do it right.

 

One area you CAN still use your backgear for, because only one tooth is missing is removing stuck chucks.

 

Put a block of wood in/under the chuck, braced against the bed/ways and run it backwards by hand, with the backgear engaged(avoiding the broken tooth bit of course).

You’ll soon get the technique for your own lathe once you get a stuck chuck, lol.

 

I did mine in aluminium because it deforms to any tooth errors(I’m only an ama-teur and a hacker) and hopefully the aluminium is weaker than the rest of the drivetrain, so I now have a sacrificial part which can be redone by me if another disaster strikes, I cut 2 cogs at the same time and parted off in the middle, so there’s now a spare small cog lying somewhere in the pile of junk and swarf littering my workshop.

Edited By ady on 11/02/2011 10:39:14

[TerrydParticipant @terryd72465]

Hi Richard,

 

I’ve not heard of ‘spherical’ cast iron, did you mean spheroidal cast iron or is ‘spherical c.i.’ something I’ve not come across before?

 

As far as I know (I’m no expert in metallurgy) spheroidal C.I. contains spherical nodules of graphite which gives it ductility rather than the brittleness of normal C.I.

 

Regards

 

Terry

[Philip PowellParticipant @philippowell34749]

Hi Ady

 

Quite a story there. I would never have thaought of making a gear from aluminium as I thought it would be too soft, you have proved otherwise.

 

“One area you CAN still use your backgear for, because only one tooth is missing is removing stuck chucks.”

 

I suspect thats how the gear was damaged in the first place.

 

Thanks for sharing your repair.

 

Phil.

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