Screw cutting chart ML4

[gasteksouth@gmail.comParticipant @gasteksouthgmail-com]

Hi, I have just bought an ML4 type machine and I’m trying to figure out how to get the finest thread pitch to use as a cutting feed. I did this at college donkeys years ago but all I can remember is drivers over driven mantra and not much else. It’s probably easier to just follow a chart if anyone has one available they could send me. Thanks Martin

[BazyleParticipant @bazyle]

It is much simpler than a chart. Just  – littleest  gear drives bigger gear several times depending on what you have.

[Martin of WickParticipant @martinofwick]

Try the myford lathes groups on io groups forum.

Failing that go to   https://bilar.co.uk/cgi-bin/change-gear-calculator.pl

for an online calculator (other online calculators are available).

Or here….. https://www.model-engineer.co.uk/forums/topic/ml4-screw-cutting-change-wheels/

[JasonBModerator @jasonb]

The chart in this post has the feed options too

[Martin of WickParticipant @martinofwick]

so the finest feed you will get, assuming you have a full set of gears (20/55 25/60 20/65), is a shade under .006in per rev. Seems quite coarse to me, if you want finer you will need some larger gears (assuming they will fit).

[GeorgineerParticipant @georgineer]

I have an original ML4 handbook which I am happy to pass on, but I shall have to find it first…  Send me a p.m.

George

P.S. I think I remember seeing a scanned copy on line.

[Howard LewisParticipant @howardlewis46836]

Helping someone who had bought a ML4, I produced a fine feed for him, using extra gears.

The set up was 20:60/20:60/20:60 This gave a fine feed of 0.0046″/rev

He lacked the studs, so I made those, filing away one end of the stud placed nearest to the Spindle, and fettling the slot in the Banjo, to allow the entire train to mesh with a little backlash (A piece of paper fed into each mesh, starting at the Leadscrew end, and finally swinging the Banjo for the the mesh with the 20T on the Spindle.

He also lacked sufficient gears. A 60T from a ML7 was modified by drilling a 3/32″ hole for the pin, using one of the other gears as a jig. (Unfortunately, to do this the “jig” had to have the pin hole drilled right through). The ML7 60T was drilled opposite the keyway.

Despite have a full set of Changewheels, he had no interest in screw cutting; just wanted a fine feed.

To keep his costs down, I made him a couple of 20T gears

Howard

[Howard LewisParticipant @howardlewis46836]

The finest pitch screw thread that you can cut will be determined by the highest ratio that can be set up between the Spindle and Leadscrew.

The Leadscrew is 8 tpi.   As an example, if you wanted a 40 tpi thread (For a micrometer like adjustment) you would need to set up a 5:1 ratio between Spindle and Leadscrew. This would need to be a compound train, and might result in the Leadscrew rotating in the opposite direction than you want for a right hand threas.

In which case you would need to insert an Idler into the train, to fix the problem, if your machine does not have Tumbler Reverse (Not all did; it was an optional extra)

If you do not get a screwcutting chart, it would be worth buying No 3 in the Workshop Practice Series, “Screwcutting in the Lathe”, by Martin Cleeve.

HTH

Howard

[Martin KyteParticipant @martinkyte99762]

As the ML4 has an 8 tpi leadscrew the standard table of gears for the Seven series should work.

regards Martin

[Michael GilliganParticipant @michaelgilligan61133]

Surely following Jason’s link in post #756071 provides all the information required [?]

MichaelG.

[Author]

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