Author Topic: hardened or tough gears  (Read 725 times)

Online berger

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hardened or tough gears
« on: 18.03. 2018 14:28 »
are there any lathe turners out there who could give advice on turning gears stamped EN 36 without having to soften them.

Online chaterlea25

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Re: hardened or tough gears
« Reply #1 on: 18.03. 2018 21:25 »
Hi Berger,
There are special tool tips available to machine hardened steel, Interrupted cuts may cause problems ??
They are not cheap though  *ex*
I bought a pack of them from an ebay seller at a good price  ;) to fit a holder I already had
It depends on what lathe and tools you have to work from
Maybe the gear could be ground instead of turned?
If you show us exactly what you want to achieve then maybe further suggestions will appear ??

John
1961 Super Rocket
1963 RGS (ongoing)

Online berger

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Re: hardened or tough gears
« Reply #2 on: 18.03. 2018 22:18 »
thanks for the reply ive got a long bed myford ml either 3 or 4 but since posting ive been in touch with experienced older brother and asked him to help out because he has experience and i have little. ive not got a modern fone yet so carnt do pics and computer doesent even let me post emoji things they come out as just dots dashes etc . *????* *conf* ;) *smiley4*see what i mean.anyway to the job, it is to turn down a 17 tooth gear made from EN36 to the same width and shape as the 19 tooth rrt2 gear to make a lower 1st gear ratio.ive got the 26t for the layshaft from a65 box and by doing it this way i can keep all the EN36 gears and drive dog formation . big brother has got myford ml7 , super7 and a big 8" centre one plus miller/ heated workshop etc [weve only just got nodding again after loseing brotherly love ] i have been imformed the best attempt is for him to use carbide tooling lots of coolent, small cuts and slow speed . i will leave him with it, if i were to attempt this my lathe might end up chattering down the garden path,if any body has other ideas or has turned this metal advice is most welcome cheers.

Online chaterlea25

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Re: hardened or tough gears
« Reply #3 on: 19.03. 2018 01:05 »
Hi,
That's an interesting project,
I also have an RRT2 box and was intending to fit a STD first gear, but found that the dogs are different
I have a pair of STD third gears that are the same tooth numbers as RRT2 and will will mate up with the first gears
I also have an A65 box that I had not thought to look at *conf2*
Late A10 gearboxes have EN36 gears

Go for using the biggest and heaviest lathe to reduce the chances of vibration
I have a Colchester Triumph 2000 and a Harrison 165 lathes which are good and heavy
I have machined bearing races with the insert tooling, BSA steering races are fkn hard  *work*  *ex* *ex*
These tips slice through present day ball and roller races *good3*

John
1961 Super Rocket
1963 RGS (ongoing)

Offline duTch

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Re: hardened or tough gears
« Reply #4 on: 19.03. 2018 03:34 »

 Sounds like Beezer Bill's gearbox, maybe  you've read about it ?
 I like the idea, but  a logistical nightmare ;

  http://www.bsa-a10.hailwood.com/billsgearbox.html
Started building in about 1977/8 a on average '52 A10 -built from bits 'n pieces never resto intended -maybe 'personalised'
Have a '74 850T Moto Guzzi since '92-best thing I ever bought doesn't need a kickstart 'cos it bump starts sooooooooo(mostly) easy
Australia

Online berger

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Re: hardened or tough gears
« Reply #5 on: 19.03. 2018 13:29 »
charterlea25 you posted on brit bike forum in 2013 and theres a guy called johny D who posted at the bottom of that page , i am following what he says on there to keep the drive dog arrangement. i do agree about BSA bills page , it blows my single brain cell apart  *eek*[ mmm no emoji] try *sad2* .i like your machine set up dad had a big colchester, my problem was too much pub with mates,but ime sure brother will use his big lathe as hes clued up and casts and machines model steam engine parts, even makeing  his melting thingy[very proffessional ,and the burners] i will wait for the result of the gear and IF is a f@@k up ive got a couple more.

Online berger

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Re: hardened or tough gears
« Reply #6 on: 19.03. 2018 13:50 »
looks like my steam computer does some emojis and not others, regards bearing races dad used to say , its glass hard or its butter from china  ;D

Online chaterlea25

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Re: hardened or tough gears
« Reply #7 on: 19.03. 2018 22:52 »
Hi Berger,
An awful lot of (not good) things has happened to me since 2013
I do not remember that thread on britbike,
Do you have a link to it/
John
1961 Super Rocket
1963 RGS (ongoing)

Offline Sluggo

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Re: hardened or tough gears
« Reply #8 on: 20.03. 2018 07:15 »
That is no easy feat or challenge.  Possible but takes extensive metallurgy skills as well as experience to do successfully.   I cant say for sure, as I only know the principles, not the specifics from my experience in manufacturing, But typically most sprokets and gears have a soft inside and very hard surface of which the depth of this hardening varies greatly depending on a lot of variables.

In aerospace manufacturing we did this to very rigid and consistent stds, and as long as you followed the tech materials you got a consistent result.  But in Non aerospace apps,, quality and consistency varied a great deal.
BSA had exemplary mettalurgy to a point in their day because of their other business interests, but by todays standards its night and day difference.

Bt for comparison, for many years on Nortons, and to a lesser degree other makes it was common to machine or grind down 530 sprockets to take a 520 chain, But sensibly now many vendors are offering CS sprockets in a 520 width so you dont hear about it as often, But the initial issue was wildly different results depending on who did the work.  Some ended up with a sprocket soft as butter.

My wife deals with this daily as "Logistics lead" in scheduling machine jobs, vendors and suppliers, customer and which machine group she sends out each job to. Some materials its better to make it in a softer material and the post manuf process to specs, Some materials its better to start with a tougher metal, only a very experienced machinist or the engineers who set up the jobs can say, In manufacturing it also depends on material availability and timelines.

Here is what a typical supplier has to say about EN36:

Applications:
As a carburising steel grade it is suitable for roller and ball bearings of extra light section, aeroplane and motor crankshafts requiring hard surfaces for roller paths, connecting rods with case-hardened ends, as well as highly stressed gudgeon pins, gears and certain types of collets

Carburising / Case Hardening:
Case hardening will give a hard wear resisting surface and a tough core strength EN36. Surfaces must be free from dirt and grease, and of low sulphur content. Case hardening can be carried out in salt baths with selected content depending on the type of salt and the depth of penetration required. Other considerations during the heat treatment process include the type of furnace, quenching medium and work piece transfer facilities. Time, temperatures and salt selection will be advised by your heat treatment provider.

Softening:
If it is necessary to soften the EN36 for machining between the carburising and subsequent heat treatment stages, heat to 640-650°C. Soak at this temperature for 1 to 2 hours and cool slowly in the furnace or in air.

Heat Treatment:
Heat treatment temperatures, including rate of heating, cooling and soaking times will vary due to factors such as the shape and size of each EN36 steel component. Other considerations during the heat treatment process include the type of furnace, quenching medium and work piece transfer facilities. Please consult your heat treatment provider for full guidance on heat treatment of EN36 case hardening steel.
Remember that any advice received on a free internet forum is generally worth about 1/2 of what you paid for it.
We overcharge every 3rd customer to pass the savings onto you.
You can have High Quality, Low price, and fast turnaround. Pick any 2, Never all 3 at the same time.

Online berger

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Re: hardened or tough gears
« Reply #9 on: 20.03. 2018 15:29 »
hi john ive had a look and was able to come up with WWW.britBike.com/forum/   then search for rrt and rrt2 1st gears, ive found it worked and got me to the page you are on and johny d a few posts down. had a text from big brother and gear turning was a success , very slow not above 400rpm apparently and lots of coolant useing solid carbide *smile* sluggo very interesting read cheers

Online chaterlea25

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Re: hardened or tough gears
« Reply #10 on: 25.03. 2018 22:36 »
1961 Super Rocket
1963 RGS (ongoing)