New Myford ML4 Owner in Need of parts

[castingflameParticipant @castingflame]

Hello to you all

I have been after a lathe for the last 5 years or so. More recently some little jobs have become a royal pain not having the facility of a lathe so I finally took the plunge and purchased a Myford ML4 from eBay that was quite local to me in the UK. It’s a perfect size machine for my limited available space and should serve me well.

I am however missing a couple of items.

1. The gear wheel on the main shaft for the tumble reverse.

The Shaft is 7/8″ with a depth of 1/2″

And it needs a gear like this one…

2. The gear ‘set’ or ‘pair’ on the back gear spindle.

Which should be the same as this one, although I do not know how many teeth each gear should have,,,

Any info and advice to help identify the back gears and availability to purchase both items would be greatly received.

Many thanks

Paul
aka castingflame

[Howard LewisParticipant @howardlewis46836]

Being a Myford, the gears are likely to be 20 DP, 14.5 pressure angle.

(You can check with one of the changewheels, if they mesh nicely with the gears on the spindle)

Count the number of teeth on the pinion that meshes with the 65T wheel. The sum of gear teeth should be the same for both meshes.

(65+ pinion) = (30+ gear)

Normal Myford changewheels are 5/8″ bore, so MIGHT fit the shaft, without need for bushing or boring.

But you may need to make a collar, to retain it, and possibly a spacer to separate it from the other gear.

Probably teaching grand ma to suck eggs, but NEVER engage Back Gear and normal drive to lock the spindle to remove a stuck chuck. A sure fire way to break gear teeth!

There are safer ways!

Check on Lathes UK website for more info.

The ML3 and 4 are 3.5″ centre height, (ML1 and 2 were 3.125″ centre height. Even numbers were longer centre distance than the odd) and depending upon age, 7/8 BSW, 7/8 x 12 tpi, or if very late, possibly 1.125 x 12 tpi (But not with the 1.250 register of the later 7 Series)

HTH

Howard

[Howard LewisParticipant @howardlewis46836]

P.S

Of you measure the tumbler gears, you should be able to calculate the PCD of them. If you measure the centre distance, between the spindle and the tumbler gear, you should then be able to calculate the PCD of the Spindle gear.

Knowing the PCD should allow you to calculate the tooth count for the Spindle gear

If unsure of the formulae and calculations, buy Ivan law’s book on “Gears and Gear Cutting”; No. 17 in the Workshop Practice Series.

Howard

[SillyOldDufferModerator @sillyoldduffer]

Welcome Paul,

Missing parts are one of the hazards of buying second-hand and finding spares for long out of production machines can be difficult and/or expensive.    They turn up on ebay and asking on sites like this helps.  As far as I know, there isn’t a seller of Myford spares who carries this stuff,  so luck and patience kick in.

The gear set needed for screw-cutting and fine-finish as supplied with the lathe can be extracted from the manual.

Myford also sold extras:

Whether or not all these gears are needed depends on what you do, but Myford recommended buying another 20 toothed gear, and, if you have to cut metric threads, then 127 is the bees knees,

At this point I start guessing, so let’s hope a Myford expert will confirm.   I believe the gears are 20 DIametral Pitch, 14.5 degrees.  This is an early standard, but still widely available new.   Unfortunately, the standard covers the gear form, but not how the gear is attached to the shaft.   Not a showstopper, but a modern gear or one of the right size from an old machine will  have to be modified to fit the lathe’s shafts.  Maybe adding bushes, boring out, or adding a keyway, screw-fixing, or clip.   All do-able after a little experience has been gained, but unwelcome for beginners and those wanting to get on and make stuff rather than fix machines.

3D-printing is another alternative.   Find a kind person who can design gears in CAD and then have them printed either in plastic, or metal, or CNC cut.   Plastic 3D-printed gears are cheapest,  they don’t last as long as metal,  but are better than might be imagined.   There are commercial firms doing this work, like igus, but I have no experience of them.  Joining a club is a good way of finding ‘a kind person’.    Volunteers are less likely on the forum, probably because they don’t want to get sucked into doing favours.   Fair amount of time taken to 3D print gears, and we’re all busy!

Dave

 

[Brian WoodParticipant @brianwood45127]

The gear on the tumbler reverse end of the spindle is 25 teeth, 20 DP with a pressure angle of 14.5 degrees.

The twin gears making up the swinging back gear cluster will need to be calculated  to give a reduction of somewhere between 1:6 and 1:7

These too will be 20DP and of 14.5 degrees pressure angle

I can also confirm the bull wheel as having 65 teeth, that will be 1 inch bore to fit on the lathe spindle, and the DP and PA detail will match those listed above

Brian

 

 

[Robert Atkinson 2Participant @robertatkinson2]

OR

You could fit an electronic leadscrew kit:

Presentation

Is the one I chose.

[Lee RogersParticipant @leerogers95060]

As I said in another recent post , the Drummond/Myford enthusiasts group on facebook is the place to find spares and help.A friendly group that will point you in the right direction. Facebook groups are like pubs , some are nasty but some are perfect for Sunday lunch with your family.

[Howard LewisParticipant @howardlewis46836]

WILD guess, but the pinion for the Back Gear , to mesh with the 65T Bull Wheel could be 20T.

Since that tooth count would be 85, the 30T would mesh with a 55T gear on the back Gear cluster.

This would given overall reduction of  5.96, which would be about the sort of ration to be expected from a back Gear set up.

Howard

[castingflameParticipant @castingflame]

Thankyou guys your help is very much appreciated.

Info for anyone else who may stumble upon this thread in the future as info seems a bit sparse on the ML4.

Howards Comment  was spot on correct for the gear sizes.
Gears on the 1″ Mandrel Shaft
65 teeth on larger
30 teeth on smaller

Gear cluster on the 1/2″ Back Shaft (now fitted)
55 on larger
20 on smaller

Which gives a reduction of 5.96:1

I am a bit late to the game at 55 years old and the imperial fraction v imperial decimal v metric is so fun 🙁 🙂  !
Soaking it all in like a sponge reading lots and watching lots. I will get Ivan’s book in the very near future when funds permit at I confess the calculations and terms makes my head hurt so I need to get to grips with that.

I am a long term 3D printer owner so today (many weeks after this initial thread) I will be printing a complete set of change gears. I do have a steel set but as the back gears are noisy, I thought I would try making some. I will also design and print the back gear cluster when I have a little more time. I will be using a Nylon/Carbon Fibre filament material as it should hold up well. Time will tell.

Thank you all again, your help is very much appreciated.

Kind Regards, Paul

 

 

 

[Howard LewisParticipant @howardlewis46836]

The fasteners will all be BSW , BSF (or BA for gib strips)

The Whit form fasteners will be fractional sizes, but a lot of other things are likely to be the decimal equivalent of an Imperial fraction

As you can see, the changewheels will increment by 5 from 20T upto 65, or  maybe even 70T.

It might be worth triplicating the 20T, and the 60T , or 65 and if room,  70T gears.

Meshing steel gears with 3D printed ones should decrease the noise levels, so you can use the existing changewheels with your home printed ones.

With these you can then set up (Having made extra studs, and possibly fettled the slot in the banjo), to get a fine feed, 20:60/20:60/20:60)  One side of one stud will need to be radiused to allow it to go right to the spindle end of the slot in the banjo.

This should give feed of 0.0046″/rev . A triple 20:65 reduction would give a feed 0.0036″/rev.

20:70 ratios should give a feed of 0.0029″/rev

But since this is a two stage reduction, the tumbler reverse will be needed to ensure that the saddle moves towards the chuck.

A slight radius on the nose of the tool should give a fine finish

It may be an old machine, possibly approaching 75 years, but can still produce good work, within its limitations, and quirks, (Such as 80 graduations on a handwheel for a 12 tpi leadscrew).

Obviously intended for use with HSS tooling rather than carbide (Which may not have been invented when it was designed)  In any case, the spindle bearings are not suitable for the high speeds needed to optimise carbide tools.

If you want to fit a 4 jaw chuck, (A most useful accessory at times) you will need to make a special backplate, or an adaptor (Don’t forget to put flats, so that it can be removed!) to the 7/8 BSW or 7/8 x 12 tpi spindle nose, from the 1.125 x 12 tpi Myford standard plates that are available, before facing and turning the OD to register the chuck

Howard

[Howard LewisParticipant @howardlewis46836]

P.S

If you don’t have them, maybe some books on lathes might be useful for a newcomer.

L H Sparey “The Amateur’s Lathe” has for may years been the “bible”. It is based about the Myford ML7

Others that would be suitable are Stan Bray “Basic Lathework” (Workshop Practice Series 45)

Harold Hall “Lathework – A Complete Course” (Workshop Practice Series 34)

To gain experience, and to make the machine more versatile, I would advocate making some basic tools.  In this way, you will become familiar with the machine, gain experience and confidence, and have a few items that will be useful in the future.  P M me, with an E mail address, if you want more details

Howard

[noel shelleyParticipant @noelshelley55608]

The bull wheel may be a 16DP, on the S7 this is so from memory. As for 1/4″ BSF, I have lengths from 3/4″ to 4″ if thats any help to anybody. Noel.

[BazyleParticipant @bazyle]

When printing the gears look out for elephant’s foot. I wonder if having carbon fibre in the mix will actually provide a rough surface that increases wear. Perhaps also make a plain one of the commonly used numbers and compare them – reporting back which is best in due course.

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