Brad93
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- Essex, United Kingdom
Harrison 140 has a forward/reverse lever and a clutch.I don’t understand what’s going on here. Are you getting to the end of the threaded section, disengaging the feed, winding the carriage back to the start by hand and re-engaging the feed?
If that’s the case then don’t disengage the feed. Reverse the spindle rotation to bring the tool to the start of the thread and go again in forward direction without disengaging the feed. If you don’t have reverse on the motor because it’s not wired up you can rotate the chuck backwards by hand to bring it to the start. I’m not familiar with the Harrison’s but you may be able to disengage the spindle clutch and throw the feed direction lever to reverse the feed direction rather than the rotation of the spindle. If it’s got a single dog type drive like my woodhouse it keeps the relationship between the tool and the thread.
I have always threaded like this, but it’s easier on newer machines with a forward and reverse clutch rather than having to stop the motor or change feed directions.
Disengaging the clutch doesn't affect the coupling between spindle and leadscrew.
most Metric threads you can disengage the half nuts to wind the carriage back manually, then use the thread dial indicator to pick up the threads.
However, 1.75mm pitch, you cannot do this.