Old Lathe Threading Woes........what I Learned

[Charles Spencer]

I also have a South Bend heavy 10L (my first lathe), but still struggle to make proper threads. I'm pretty certain it's me and not the lathe... The difficulty I have is making sense of depth of cut. At an angle, the cutter isn't cutting as deep as the dial says and I understand this (it's at an angle after all...). Is there a quick rule of thumb for gauging depth of cut by the compound dial, or should one simply cut, measure, cut, repeat...?

I use a dial indicator.

 

[Wreck™Wreck]

I also have a South Bend heavy 10L (my first lathe), but still struggle to make proper threads. I'm pretty certain it's me and not the lathe... The difficulty I have is making sense of depth of cut. At an angle, the cutter isn't cutting as deep as the dial says and I understand this (it's at an angle after all...). Is there a quick rule of thumb for gauging depth of cut by the compound dial, or should one simply cut, measure, cut, repeat...?

.866 of the dimension moved with the compound at 30 Deg.