ML7 Genuine Gears vs Replacement

I'm intrigued by the idea of a set of change-wheels becoming completely worn out. Lathe must have done a helluva lot of work.

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I agree completely, Brian

That story may, in itself, reveal the ‘special’ feature of Myford at Beeston ... They did things in ways that we can relate-to, and with a level of skill and dedication to which we can aspire.

I have never seen the new manufacturing facility, but it would be good to think that the spirit persists, even if the processes have been updated.

MichaelG.

Maybe he got the gears off one of Martin Cleeves' Myfords used for commercial screw manufacturing? Could be historic gears them. Wonder where the matching lathes are?

Like I said earlier, I have bought almost two full sets of change gears secondhand and never seen a worn out one. So I suspect the ones in question came from a machine that was exceptionally well used. Possibly in a commercial workshop or a production environment. Or a very very enthusiastic string of model engineers. The change gears on my Drummond have been going since 1937 with no noticeable wear of the ilk described. My ML7 since 1957 and ditto. The bed was worn out. The gears appear just fine, including the standard set of fine power feed gears that appeared to have been on the lathe all its life.

That's not to say there is anything magic about Myford gears. They were just common a garden cast iron gears, cut as we have been told, in a milling machine with a dividing head. Pretty standard stuff for small to mid-volume engineering works of the era. It's just that they don't transmit a lot of power, don't get a lot of use in hobby shops, and are in a pretty friendly low-rpm environment free of abrasive grit, heat etc So normally do not see much wear of the type described.

Yeah, I wonder what the rest of the lathe looked like?

Edited By Hopper on 10/05/2020 11:51:30

Some of us on the west side of the Atlantic are using 3D printed plastic gears for our change gears. They are cheap as dirt to print and with minimal CAD skills we can create gears with any number of teeth to fit any diameter of shaft. The plastic gears have different wear characteristics than metal gears which may be an advantage but in any case, once the gear is designed and the CAD file saved, one can remake any of the plastic gears for pennies.

The plastic gears have different wear characteristics than metal gears which may be an advantage but in any case, once the gear is designed and the CAD file saved, one can remake any of the plastic gears for pennies.

I agree with the first part and intend making some, initially in PLA, even though I don’t actually need any change gears.

However, I am intrigued as to how you cost them. I reckon a couple of quid, or more, is realistic

I’m only a beginner with my printer and I have not got so far as to try cheap filaments, but it seems as though it would take hours to print a fairly solid gear? Thinking, here, of perhaps a 50 tooth DP14 gear about 9//16” thick.

Gears for Myford MlLlathes, are to the best of my knowledge 20DP and 14.5 pressure angle.

More modern lathes are likely to use 20 P A, so should not be meshed with 14.5. Maybe an incorrect mixture is responsible for the incorrect meshing?

Broke for lunch

I have cut 20 DP gears in steel, for use on my ML7 and for others ML4s, without apparent problems in use.

In some of the more modern machines, (using Module gears ) I suspect that Plastic gears are used as a weak link in the drive, so that they fail before more expensive parts are damaged.

If it needs to be said, gears should not be run without backlash, since this promotes noise, and more importantly, wear.

A suitable way of setting backlash is to run two thicknesses of writing paper through each mesh. I usually start with the mesh with the gear on the Mandrel, or the Tumbler Reverse, since these are fixed in position, and work my way down the train towards the Leadscrew.

As Hopper says backlash should not be a problem when screwcutting, as long as a suitable space is allowed before the tool engages for the next cut, to ensure that backlash has been taken up.

HTH

Howard  Fat fingers strike again!

Edited By Howard Lewis on 10/05/2020 14:46:23