Sieg SC2/SC3 what involute cutter for gears?

[Jim F]

PSA, a 127/100 transposing gear is 7" dia., the thing is huge, for a SB 9.

 

[royesses]

Mini Lathe is Module 1, 20° PA.

Roy

 

[addertooth]

Thanks Royesses. I appreciate that answer. I didn't want to start forming an involute cutter collection.

 

[Downunder Bob]

PSA, a 127/100 transposing gear is 7" dia., the thing is huge, for a SB 9.

Yes a 127 gear is rather large for smaller lathes, but it is the smallest gear that will give you an exact metric pitch. There are various other combinations that can be and are used un smaller machines,many of these combinations give threads that are quite usable for nuts and bolts. however they are not suitable for long threads such as leads crews as the error does accumulate.

There are many calculators around, both on HM and other sites that will give you all the info you need.

Also I have seen photos and drawings of ways to fit a127T gear onto a smaller machine if the accuracy is desirable.

 

[Jim F]

Yes a 127 gear is rather large for smaller lathes, but it is the smallest gear that will give you an exact metric pitch. There are various other combinations that can be and are used un smaller machines,many of these combinations give threads that are quite usable for nuts and bolts. however they are not suitable for long threads such as leads crews as the error does accumulate.

There are many calculators around, both on HM and other sites that will give you all the info you need.

Also I have seen photos and drawings of ways to fit a127T gear onto a smaller machine if the accuracy is desirable.

I had one 3Dprinted, it just barely fit his machine, I will be doing threads that need to be right on, not just close enough.