Sourcing small metal gears

[Sam_Q]

Hey guys, I am looking for some some gears which are roughly 5 to 10mm wide and 20 to 50mm diamater. I want these to be made to steel to handle a decent amount of torque and have straight cut teeth. I am looking to make my own 2 speed gearbox with dog engagement for a 40cc 2 stroke engine. I will given the choice have an under-drive/over-drive combination with a manual gear change using a spring to hold it in gear.

Does anyone know of any device thats available that I can take apart that has some metal gears like inside? I only need the gears, I will make the shaft and the dogs myself.

-sam

[LeeRoy]

There are actual places that only sell gears. Either buy some from there or have a gear cutting place make you some.

[Billzilla]

Try the gears from a reduction starter.
(again! )

[Ben Wilson]

Lathe thread cutting gears might be what you are after...

[Sam_Q]

ok thanks guys, I will have a look at a 5sfe reduction starter, there where a few of them at the wrecker

Other than that I was thinking maybe a washing machine gearbox would have something

[Duk]

Lathe thread cutting gears might be what you are after...

Prease be expraining this to me
Unless machining a worm gear, how can a lathe be used?

[Sam_Q]

I thought he meant the change gears for the thread curtting auto feed. These are the gears that move the spindle to adjust the motion of the cuttering tip to cut the thread.

But hey I may be thinking of something else tottaly

[Duk]

I thought he meant the change gears for the thread curtting auto feed. These are the gears that move the spindle to adjust the motion of the cuttering tip to cut the thread.

But hey I may be thinking of something else tottaly

Yes a moment of blatant stupidity from yours truly, especially when I'm a fitter and machinist.........

[oldcorollas]

why not bike gearboxes?

[Sam_Q]

way too heavy, I want the whole box when finished to be about 1kg

[oldcorollas]

i mean take the gears from inside the bike gearbox... thye are small, you could machine them thinner, and you know they will be strong enough.

or, use chain and sprockets....

[madmont]

some electric drills have 2 speed gerboxes

[styler]

in pitbike motors the:

lifan
ducar
yx

have gear sets approx 20 to 50mm in diameter,
and im not sure maybe 20mm wide?

all handle 140cc 4 stroke power of 8 to 12hp.

hobby stores might be too small but heres one:
http://www.smallparts.com.au/catalogue/individual/

[Sam_Q]

madmont: funny enough I stripped the gearbox of my drill on the day you made that post and thy arnt made very strong.

styler: that probably would of been my next port of call but I think if I go down this road I am going to just use chains and sprockets like what corollas is suggesting. This is a good option because I can drill my own sprockets and then I can make them have integral dogs for a nice light and compact design, I will see

so thanks for the help guys

[styler]

hey i have a lifan pitbike gearbox apart here and it has
10mm wide gears, ranging in diameter from 20 to 50mm or so...
straight cut too they also use a conventional dog gear design
i can do pics with a tape for mm measurements if you want?