ML7 Genuine Gears vs Replacement

[not done it yetParticipant @notdoneityet]

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.

[Howard LewisParticipant @howardlewis46836]

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

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