Blunt Starting Threads

[SICDLtd]

I've been having a bit of a play about trying to blunt start at thread in my ST-20. I've used the same threading cycle with a grooving tool just editing the offset and the Z finish position accordingly.

The machine is successfully wiping the thread but the ramp out is slower than I'd like. First try was at the same speed as the threading cycle but I've tried slowing the RPM right down to 100 RPM but the result hasn't changed. The ramp out seems to take approximately 1/3 of a turn of the spindle at both high and low speeds which makes me think that the retract is somehow linked to the threading cycle and not the machines rapid speed.

Does anyone have any suggestions?

[J_Copeland]

M24 is straight off,M23 is ramp off


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[SICDLtd]

Thanks for the suggestion. I tried both but it didn't seem to make much difference.

[Lynn R.]

Make sure the rapids are at 100%
Settings 95 and 96 conrol the chamfer angle and degree of retract. Maybe change these?

[SICDLtd]

Thanks for that, I had a feeling it might be something to do with a setting somewhere due to the fact that the ramp out was the same regardless of spindle speed. I'll give it a go next week! 👍

[SIM]

You can find more information looking up the term Higbee thread.

Yes, adjust the settings to change ramp angle as well as the Z start position.