Metric thread on an ML7

Go here and use "other lathes" and it will give you all the gear changes for your gear set and tell you the error if any. Also remember you have to leave the threading handle engaged and use reverse to back it back out for next cut... Jim the yank

Thanks for the suggestion Jim. I'd already taken a look at it but have not tried to use it. Once I make the effort to find the limits of what will fit on the banjo I'll give it a go. The Duncan Munro software does a similar job and is specific to the Myford ML7 so has the facility to use 6 gears as well as 4. Digging around a bit more I think I have found the answer to the basic problem. I either need special gears that will fit on the existing banjo or a bigger banjo to enable the 127 gear to be used. I've yet to check but suspect that previously I had cut a metric thread of less than 1.5mm and that needed a bigger reduction ratio that enabled the smaller gears to fit on the banjo.

Cheers Henry

In the LMS program you type in all of the gears you have and leave out the big 127 gear and see what they give for a solution, type in even doubles if you have any. Sometimes the error is so small you wont notice in perhaps .5mm or so?

In the LMS program you type in all of the gears you have and leave out the big 127 gear and see what they give for a solution, type in even doubles if you have any. Sometimes the error is so small you wont notice in perhaps 12mm or so?

Thanks for encouraging me to give it a go Jim. I eventually gathered all the information and it did indeed come up with usable answers for several metric threads which I printed and now have on hand when needed.

Cheers Henry

My neighbour borrowed a ML7 metric cutting kit from another neighbour and it was a true conversion with the 127 wheel and IIRC it wouldn't fit within the standard cover so I doubt HSE would be impressed with the exposed gears but it did the job and IIRC did use a larger banjo or extension for it. All subsequent metric cutting has been done on my Harrison M300 which does both TPI and metric but I think it is pseudo metric, close enough for most things but not absolutely correct as the lead screw is inch.

thumbs up!

The 127 tooth gear or equivalent should take care of that inch lead leadscrew. It has on every lathe I have run. Being in the USA metric leadscrews are not so common. As everywhere else. Eric

The 21 tooth gear is an option you can buy from Myford I found the best solution is to buy one of these.

Thanks to a reply to my 2017 message I was able to set up a compound train using the existing standard gears. There is a nice bit of software that does the calculations for a wide range of thread pitches.

Cheers Henry