34 mm x 2 thread?

[Menessis]

OK one of these days I want to make a part that needs a metric thread. I have a SB Heavy 10. Double tumbler gear box. The thread is 34mm x 2. So how do I go about figuring out what I need to do in order to get it done?

Thanks for any help.

Menessis

 

[Ken-Bergen]

OK one of these days I want to make a part that needs a metric thread. I have a SB Heavy 10. Double tumbler gear box. The thread is 34mm x 2. So how do I go about figuring out what I need to do in order to get it done?

Thanks for any help.

Menessis

If you want it exactly 2mm pitch you'll need metric transposition gears.

 

[Menessis]

I was just reading a bunch of your threads on the subject of metric threads.

Menessis

 

[kitno455]

You have other, less expensive choices, if you are willing to accept a basically immeasurable error.

1. Replace the 56t gear on the gearbox input with 79t. This will make the leadscrew act like it is 2.2506mm pitch instead of 8 tpi. Then you can cut the following threads:

MMpT Gearbox
3.0009 6
2.0006 9
1.5004 12
1.0003 18
0.9003 20
0.7502 24
0.6002 30
0.5001 36
0.4501 40
0.3001 60

2. A more general solution is to get a 63 tooth gear, and permanently attach it to the outside of your 80t idler gear. Then when you want to do some metric pitches, move the 56 tooth gear on the gearbox input outward, by swapping it with the spacer. This makes the leadscrew act like it is 2.5003mm pitch. Then you can cut the following threads:

MMpT Gearbox
2.5003 8
2.0003 10
1.2502 16
1.0001 20
0.5001 40

The second option is more general because it gives you the option to also adjust the stud and screw gears to pick up the rest of the metric pitches, using the regular south bend scheme (but without the expensive 100/127 compound).

allan