Okuma LS Gear Specifications

jwatts · Oct 4, 2022

I haven't been able to find much information on the gears used in the LS lathes. Does anyone know the specifications for the 50 tooth output gear (some are phenolic) and the 63 tooth gear attached to the gearbox?

johnoder · Oct 5, 2022

It will have an OD and a countable number of teeth. It was made in the sixties and will likely have a 20 degree pressure angle. The tooth size will be one of the Module sizes and these are related to both OD and pitch dia.

A way to start understanding that is to know a gear that is made with metric module 1 size gear teeth and there are 40 teeth will have a pitch dia. of 40mm and an OD of 41mm.
Now do some investigating and see if I got any of that wrong :ack2:

jwatts · Oct 5, 2022

I must admit, that a lot of the gear terminology is confusing to me having never really worked with it. In this case, both gears are missing so I don't know what the OD should be. Having said that, I guess if I can measure the module size of the existing gears that those mate to, I should then know number of teeth, module size, and pressure angle. Is that enough information, or will I also need to calculate the pitch diameter?

johnoder · Oct 5, 2022

jwatts said:
I must admit, that a lot of the gear terminology is confusing to me having never really worked with it. In this case, both gears are missing so I don't know what the OD should be. Having said that, I guess if I can measure the module size of the existing gears that those mate to, I should then know number of teeth, module size, and pressure angle. Is that enough information, or will I also need to calculate the pitch diameter?

Here is a not very old thread that may be helpful. A post in it says they think the 50 tooth phenolic is Module 1.5. The pitch dia of such a gear would be 75mm - and if the 63 is 1.5 Module it would have a 94.5mm pitch dia
You could post in that thread and ask what else they know.

Okuma LS 50T Phenolic Gear

Hey Group, My 18" Okuma LS lathe's 50T phenolic gear is cracked... I have a piece of 3.5" phenolic rod and was getting ready to make a new one but I have a few questions. I know other Okuma owners have replaced this gear, and a lot of others here have much experience machining gears, so maybe...

www.practicalmachinist.com

I checked my 50 tooth 1.5 module I have laying around - its 3.070 OD. 75 plus 1.5 would be 76.5 or I am wrong in my statement in above post. It is TWO mm added to 1 Module gears pitch dia for OD

Your 1.5 module 50 tooth needs to be 78 OD or THREE mm added to 75mm pitch dia

If your 63 runs with the other 1.5 module gears, its OD would be 3.839 or 94.5 plus 3 for 97.5mm

jwatts · Oct 6, 2022

Thank you for your response, I think things are a little clearer to me now. So far it seems that wherever I look to purchase gears they want a different set of specifications.

Peter from Holland · Oct 6, 2022

Formula is M(Z+2)= OD
M is the module =Pitch of the gearteeth (M1 is 3,14mm on the nominal diameter)
Z= number of teeth
OD= outer diameter of the gear in mm

Peter

jwatts · Oct 10, 2022

Thanks for the info. From measuring the existing gears I can confirm that they are Mod 1.5. So far I haven't had much luck finding these particular gears anywhere. Any suggestions on a supplier, or somewhere that would make them?

johnoder · Oct 10, 2022

jwatts said:
Thanks for the info. From measuring the existing gears I can confirm that they are Mod 1.5. So far I haven't had much luck finding these particular gears anywhere. Any suggestions on a supplier, or somewhere that would make them?

You could ask member hendeyman if he wants to make some Module 1.5 gears. Here is his email he posted sometime back
[email protected]

You could also ask Brian

Brian Miller
[email protected]
phone 618 946 0793
Miller Machine and Fabrication

Peter from Holland · Oct 11, 2022

Plenty of them around here in Europe for about €10/pc
So there must be some in the US as well Phenolic not probably but plastic/nylon ones are available
Peter

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