1929 AJS/Sturmey-Archer 3-Speed Gears

Information relating to Matchless and AJS Models built prior to 1939
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1929 AJS/Sturmey-Archer 3-Speed Gears

Postby User name » Wed Mar 28, 2018 12:11 pm

I have a 1929 350cc AJS with the 3-speed gearbox by Sturmey Archer - I've stripped it down and put some photos in the... um Photos section, in case you're interested. Anyway, the middle pair of gears are very worn and rounded and I was wondering where we stand with reproduction or NOS parts given it must be very common? The spare-parts scheme looks very good, but early pre-war (real AJS!) parts are hard to come by.

I've been in contact with a few custom gear manufacturers myself, but they are all very busy at this time of year - preparing for the summer, I guess. I haven't got any quotes yet, but it sounds as though making them as a one-off or short production run is almost insultingly easy compared to their normal business! I know there was a proposal to make some gear-sets for the square-shaft 3-speed gearbox, but it was some time ago and I have no idea what the outcome was?

Cheers! :beer:

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Re: 1929 AJS/Sturmey-Archer 3-Speed Gears

Postby cbranni » Wed Mar 28, 2018 4:19 pm

Hello Alisiter,

Replies to your post are a bit thin on the ground so this my reply...... I have a 1927 Triumph with a three speed box and is basically the same as yours in how it works, my second gear teeth were also badly smashed up but you have to expect that because that is the way the gearbox works. I am hoping to do the Banbury run next year, and last year I found a spare box to rebuild.
There are no NOS spares about and limited used parts, the bikes are 90 years old so it's a case of make do and mend.
First and third gears were not so bad but second gear was shot so this is what I did on the lay shaft (you may need to find a machine shop) set it up in a lathe turn the gear teeth off to a suitable dia and cut the lay shaft in two between two gears, buy a spur gear from HPC the same number of teeth and pcd as the one you have just turned down (count teeth first) :lol:
Have this gear machined to width and bored for a shrink fit to the newly machined lay shaft, when fitted few runs of tig just to make sure and tig weld the two shaft halves back together.

Similar for the main shaft second gear, this gear had dogs either side and a splined hole, simply set it up in the lathe turn the teeth off, once again but gear from HPC same number of teeth and pcd of your original and make sure the pressure angle is same as the one you bought for the lay shaft, then machine gear width and bore to suit shrink fit and tig weld.

Only draw back is these gears are tough but not hardened as the originals were to around 52c, the photo may help to explain. Cost of gears are about £40 each and a machine will charge I guess around £250, if you had those items made from scratch I guess over £1000.

Colin

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Re: 1929 AJS/Sturmey-Archer 3-Speed Gears

Postby User name » Wed Mar 28, 2018 5:00 pm

Now that is what I call a cunning plan! And it's even easier in my case because the layshaft seems to be keyed together.... I wonder how much you'd have to pay to get the cheap gears hardened by one of those clever non-dimensionally-distorting treatments? After welding them on! :lol: Probably better spent on trying to get the engine in tip-top condition!

Cheers! :beer:

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Re: 1929 AJS/Sturmey-Archer 3-Speed Gears

Postby Rob Harknett » Wed Mar 28, 2018 5:12 pm

I am sure these gears are available, from some one like Dragonfly ??? There was talk of them not long ago within the prewar e group.

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Re: 1929 AJS/Sturmey-Archer 3-Speed Gears

Postby User name » Wed Mar 28, 2018 5:17 pm

Really? I have looked at Draganfly for parts I could use but only remember seeing AMC and Burman gearboxes listed. I'll have to have another look. Perhaps someone got a small batch made up and sold the rest through Draganfly to cover their costs?

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Re: 1929 AJS/Sturmey-Archer 3-Speed Gears

Postby SPRIDDLER » Sat Mar 31, 2018 7:53 am

Vintage Motorcycle Spares are currently listing some NOS S/Archer gearbox parts....

http://www.vintage-motorcycle-spares.co ... r-40-c.asp

Even if what you want isn't shown it might be worth a call to them.
I poke badgers with spoons.

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Re: 1929 AJS/Sturmey-Archer 3-Speed Gears

Postby User name » Sat Mar 31, 2018 9:05 am

Thanks Spriddler - I am aware of that website, but as far as I can tell the stock (in the e-store) hasn't changed for years so I assumed they were shutting down or shut down already. I'll give them a go, but the 4-spline mainshaft only seems to have been used for a couple of years - probably less than the square-section mainshaft gearbox. I almost found a guy in Australia making them, but it turns out he got put off in the end because there were so many variants in the same/similar case that each one had to be a one-off.

I know there are hoarders out there that do have these gears, having spoken to a few of them, but I find it hard to criticise their position because it's a very human instinct. One that I have to admit to myself - just as spares, you know, just in case... :oops:

BTW, does anyone know the best way (apart from paying someone with insurance to do it) of removing the keyed gears from the layshaft? I have a small gear puller that I made in college, but I'm worried that it will deform the gears or snap a tooth or two off, as they are very tight. If the damaged gear was at the end I'd just keep winding it up... :evil:

Thanks for all your responses so far!

:beer:

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Re: 1929 AJS/Sturmey-Archer 3-Speed Gears

Postby SPRIDDLER » Sat Mar 31, 2018 9:58 am

I know very little about pre-war bikes and just came across that website whilst looking for something else.

There is an AMC Pre-War e-group website somewhere which might be worth a try.
I think the S/A 'box was used on other marques (Notrun, Royal Oilfield?) so maybe worth doing a search on their websites, or on the VMCC site?

(From here I wouldn't dare to suggest how to get the keyed gears off!).
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Re: 1929 AJS/Sturmey-Archer 3-Speed Gears

Postby Rob Harknett » Sat Mar 31, 2018 10:20 am

Rob Harknett wrote:I am sure these gears are available, from some one like Dragonfly ??? There was talk of them not long ago within the prewar e group.

I am sure quite recently a member of the prewar e group was looking for Wolverhampton AJS gears. Other members responded which resulted in the person finding parts wanted. The group member also get a lot of parts made in small batches. There are only a handful of active prewar machine owners in this club forum. The club provides a link for the prewar AJS & Matchless e group. A group with almost a 1,000 members, ( although many like yourself, are members seeking help, advice and parts ) There are however many active members that provide help and advice. There are probably spares still un used I found a few years ago. That went into the groups sheds. The hoard of parts included a wheel barrow load of gearbox bits. 2/3 barrows full engine bits. Forks, frame etc. I just built up one complete bike, half of another. Then disposed of the rest to help other bikes.

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Re: 1929 AJS/Sturmey-Archer 3-Speed Gears

Postby User name » Sun Apr 01, 2018 6:16 am

I have just had a quote back from a fairly large family-run gear cutting business in Lansashire, UK, for £680 including VAT. This is a one-off order for both middle gears, and they want the shafts as well which implies they are at least going to make an effort! They seem to be a very reputable company, and I believe they were recommended by a very busy company that specialises in racing gearbox design and manufacture, but I'll have to check my email to see if that is the case. 4-week leadtime and 10-weeks design to production.

That price actually seems fairly reasonable for a one-off custom gear pair, although it's far more than I'd want to pay for a speculative set of gears of unknown origin. I've attached the sketch I used to get the quote, in case it's any use for anyone else with the same gearbox. I do have one question, though - do the two angled sides of the gears face each other or in different directions? Logic would dictate they face away from each other to improve meshing in both directions but mine are so mangled I didn't notice the bevelling until I had dismantled the mainshaft..... :roll:

Rob - is this the yahoo wdmotorcycles group? Any chance you can recommend me for membership? Even if nobody there has any spare gears, there may be someone that wants to know about the quote.

I should say that I haven't gotten the company's permission to post details about the quote yet, but if anyone is interested just let me know and I'll drop them an email. I got the quote yesterday after 21:00(!) and they have been very quick to respond before - but I hope they at least take Sundays off, especially this one!
:beer:
Al
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