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Gallery, Projects and General => How do I?? => Topic started by: slowcoach on December 17, 2009, 03:29:20 PM

Title: Harrison L5 change gears
Post by: slowcoach on December 17, 2009, 03:29:20 PM

Hi all, does anyone out there know what changes gears are required on a Harrison L5 to cut a 6tpi thread. I have no gear chart on the lathe to guide me   :scratch:  hence the plea.

 :thumbup:
Rob

Title: Re: Harrison L5 change gears
Post by: mklotz on December 17, 2009, 03:46:27 PM

I'm not familiar with the lathe but, assuming it has an Imperial leadscrew, it should be easy to puzzle out the required ratio.

Say the leadscrew has a pitch of N tpi.  One revolution of the LS will move the carriage 1/N inches.  To cut a 6 tpi thread, you need to have it move 1/6 of an inch for each revolution of the spindle.

Thus the spindle to leadscrew ratio needs to be N/6.  Any set of gears that yields this ratio should do the trick.

Title: Re: Harrison L5 change gears
Post by: Darren on December 17, 2009, 03:54:11 PM

There are a couple of downloads here http://www.lathes.co.uk/latheparts/page14.html that will serve you better than the original charts ...  :ddb:

Select the download suitable for your lathe and away you go ....  :thumbup:

Title: Re: Harrison L5 change gears
Post by: slowcoach on December 18, 2009, 03:49:15 AM

Thanks guys, I will have a go at that.  :thumbup:

Rob