Myford ML10 main screw skating

[Bob LAGParticipant @boblag53615]

[Bob LAGParticipant @boblag53615]

Hi

Bonne année (HNY) to all!

my name is Bob, I'm French, nobody's perfect but I try to cure myself by buying a good English lathe!

I have a ML10 and I have a little problem with its apron (I'm sorry but my English is not too good!)

The gears skate on the screw.

 

With the advice of Monsieur Myfordboy, I tried to tighten the gears by adjusting the mesh with the eccentric but unsuccessfully!

2 pix + 2 videos here

May you please tell me if the shape of the gears seems correct to you (2 pix)

If I need to change them, do you know were I could find some?

Is it the screw wich have a problem?

 

Merci par avance!

Bob

[Bob LAGParticipant @boblag53615]

Hummm….you don't share any more secret knoledge….Brexit oblige…..tant pis!

Bob

[Tony Pratt 1Participant @tonypratt1]

Your gears are worn out try ebay or Myfords.

Tony

[Michael GilliganParticipant @michaelgilligan61133]

Sorry, Bob … I don’t have an ML10

But all those brass particles are surely a bad sign

I think you need two new gears

MichaelG.

.

https://www.myford.co.uk/acatalog/ML10-HAND-TRAVERSE-PINION-ASSEMBLY—METRIC–10438-1630.html

Edited By Michael Gilligan on 12/01/2021 17:36:29

[SillyOldDufferModerator @sillyoldduffer]

Patience Bob, nothing to do with Brexit! There's a delay between joining and the members first post appearing, and they sometimes appear so far down the list that no-one sees it. I missed it.

Watch this space, I expect an ML10 owner will be along soon.

Welcome to the forum.

Dave

[noel shelleyParticipant @noelshelley55608]

Hi Bob, the gears do not look to bad, and though I can not run the video the leadscrew looks OK. Has a spring holding the gear in broken? Your english is much better than my french ! Good luck Noel.

[BazyleParticipant @bazyle]

The gear may look worn but that is because it is modified to wrap round the leadscrew. I assume your porblem is that it 'jumps' and misses a tooth sometimes. This is because the depth of engagement is not quite deep enough but it is probably a difficult balance between too little and too much.
Does this happen more at one end of the bed than the other?
Does it vary if you turn the leadscrew half a turn so that the other side of any bend in it is at the top?

You may be able to raise the leadscrew a little by adjusting the bolts of the bracket at each end but this can also affect the engagement of the half nut. You can also put a shim between the saddle and the apron to lower it a little.

If this isn't clear please point out the sentence that needs more detail.

edit: sorry I didn't see your post earlier – it may have been held at teh border awaiting virus test.

Edited By Bazyle on 12/01/2021 18:02:45

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Bazyle on 12/01/2021 18:01:24:

The gear may look worn but that is because it is modified to wrap round the leadscrew. […]

.

So do the new ones from Myford just ‘bed-in’

… or have I found the wrong item ?

Please see the link in my previous post

MichaelG.

Edited By Michael Gilligan on 12/01/2021 18:10:57

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Michael Gilligan on 12/01/2021 18:09:55:

… or have I found the wrong item ?

.

.

Is anybody there ??

MichaelG.

[OldironParticipant @oldiron]

I'm here MichaelG. I agree, 2 new gears needed.

regards

[Bob LAGParticipant @boblag53615]

Hi,

Merci to everybody for these answers! I started to become parano not to have any message back!

Ok for the 2 new gears but I need another info before I order them: how can I know if my gears/screw are metric or imperial? This lathe is coming from Lyon where Myford used to have a seller, but I don't know if they were delivered metric or imperial.

Is ther any index on the screw or in the gearbox ?

Merci encore

Bob

[Roger HartParticipant @rogerhart88496]

I had an ML10 and the mesh gears looked a bit worse than yours but they did not 'skate'.

Before spending money on new gears I would have a very good look at the eccentric adjustment top and bottom. Are you withdrawing the locking grub screws far enough to get a good enough rotation?

You can get the whole apron assembly off fairly easily. Undo the righthand lead screw handle and nut and washers, slacken collar at left hand inboard end and pull the entire lead screw out from the left hand side. Then undo a couple of allen cap screws holding the apron and voila.

The imperial leadscrew is 8tpi, easily measured. Take a look inside the change gear housing to see the thread/wheel chart. That will tell you if you have a metric or imperial machine.

bon chance

[Bob LAGParticipant @boblag53615]

Hi Roger,

Merci for les conseils!

You write about a "eccentric adjustment top and bottom" …bottom is ok, but are you sure about a "top" one?

With the bottom one screwed in the uppest position, still skating….

It sems that the leadscrew is an imperial one: 8tpi

Michael, do you have another good adress for imperial spare parts? I don't see anyone on the Myford website.

Merci

Bob

[Eric LucasParticipant @ericlucas71410]

Bon soir Bob

why not remove the apron completely and remove and clean the half nuts?

use a sharp point to clean them.

take everything apart and clean and assemble again

regards

eric

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Bob LAG on 13/01/2021 18:07:04:

[…]

It sems that the leadscrew is an imperial one: 8tpi

Michael, do you have another good adress for imperial spare parts? I don't see anyone on the Myford website.

.

I have never used these people, Bob … but they do list them [pattern parts]
**LINK**

https://www.qsaney.com/index.php?main_page=product_info&products_id=266035

bonne chance

MichaelG.

[Roger HartParticipant @rogerhart88496]

Hi again. No I am not sure about an upper eccentric adjustment. But I think it is worth looking very closely in that area. There is a hole directly above the carriage handle – is this an oil hole or for a grub screw for an eccentric sleeve adjustment?

I no longer have my ML10 and cannot find a detailed enough drawing. Not much to lose by removing the carriage handle and disk and taking a look. The lathes.uk ML10 site and pictures give a hint.

If I were designing that thing I would have put in some kind of adjustment – just 'feels' as if it ought to be there – so just a hunch – could be wrong, I often am….

[Robin KingParticipant @robinking15611]

As luck would have it I've just crated up my ML10 for a house move so can't check it, but I do have the Myford owners manual to hand which has the section drawings and parts lists in the back. On section D-D that shows the upper shaft (for the carriage handle) as part no 228, and the lower shaft as part no 122.

No. 228 is the handle spindle so rotates and does not have any eccentric adjustment, but does have a groove in it for the retaining grub screw (part no. 120), visible immediately behind the carriage handle as Roger mentions.

No. 122 is listed as 'eccentric' and appears to be intended to be rotated to raise or lower the lower gear to engage with the leadscrew. If set too low it will allow the leadscrew to deflect downwards out of engagement with the carriage handle spindle gear and may be the cause of your problem – worth checking. No. 122 is drawn with a groove in it for a retaining grub screw, part no. 124, which is inserted from the right hand edge of the apron.

If adjusting 122 doesn't work then have a good look down behind the apron – I was surprised to find large amounts of swarf down there on mine, which could easily fill between gear teeth causing problems. Worth a look.

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Robin King on 14/01/2021 10:32:47:

As luck would have it I've just crated up my ML10 for a house move so can't check it, but I do have the Myford owners manual to hand which has the section drawings and parts lists in the back. On section D-D that shows the upper shaft (for the carriage handle) as part no 228, and the lower shaft as part no 122.

[…].

.

For the sake of my sanity, if nothing else, Robin …

Could you please confirm the intended shape of the gears ?

Bob’s photos are quite unlike the new parts that are on offer !!

… I have assumed this to be the result of severe wear [from scuffing against the leadscrew when incompletely engaged] but others say they are made that way.

MichaelG.

[Robin KingParticipant @robinking15611]

Michael,

Your sanity is our highest priority, of course! Maybe this'll help?

The original manufactured form of these gears is with a near semi circular form tooth machined into the bronze gear circumference so that the teeth effectively wrap part way around the leadscrew. They are not in simple straight cut sprocket form. I can understand that at first sight it might appear that the gears are excessively worn, but probably not so; that's how they were made. Thinking about it and in light of using mine for nearly forty years the only way that the teeth will wear excessively is if the gears are prevented from turning while the leadscrew rotates, either manually or due to seizing, but otherwise they are free to turn therefore wear should be minimal, assuming reasonable lubrication, adjustment, and normal handling. I'd still look at cleaning, adjustment and lubrication as the first steps before investing hard earned cash on a new set.

[BazyleParticipant @bazyle]

The pictures MG linked to show it is a pressed on brass/bronze gear. This allows two additional options.
If it is just worn find a way to partially push it off the shaft so that an unworn section at the edge is in the right place to do the job. This should give some months of additional use while you try option 2
It is engaging with a sort of rack so can be a straight sided tooth gear, not an involute, but set over at a slight angle to match the thread. It should be very easy to make a suitable cutter to make a new one.

edit: Robin has provided some additional insight not accounted for in the above.

Edited By Bazyle on 14/01/2021 12:38:45

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Robin King on 14/01/2021 12:15:53:

Michael,

Your sanity is our highest priority, of course! Maybe this'll help?

The original manufactured form of these gears is with a near semi circular form tooth machined into the bronze gear circumference so that the teeth effectively wrap part way around the leadscrew. They are not in simple straight cut sprocket form. I can understand that at first sight it might appear that the gears are excessively worn, but probably not so; that's how they were made. Thinking about it and in light of using mine for nearly forty years the only way that the teeth will wear excessively is if the gears are prevented from turning while the leadscrew rotates, either manually or due to seizing, but otherwise they are free to turn therefore wear should be minimal, assuming reasonable lubrication, adjustment, and normal handling. I'd still look at cleaning, adjustment and lubrication as the first steps before investing hard earned cash on a new set.

.

Many thanks for that Robin

The remaining issue is … Why does Myford in Mytholmroyd not supply them in that form ?

MichaelG.

[Grindstone CowboyParticipant @grindstonecowboy]

Just went out and took a couple of photos of my ML10 – apologies for the quality, it's currently stored in a neighbour's garage and not easy to get at – and the gears look just like the ones that Michael G linked to. It's a fairly late model, and in excellent condition.

Usual photo rotation problem!

So this begs the question, did the design change over the years if Robin King's have a semi-circular profile?

Rob

Edited By Grindstone Cowboy on 14/01/2021 14:33:33

[Michael GilliganParticipant @michaelgilligan61133]

Very interesting, Rob

… I think we might need one of Jason’s [unless another volunteer steps forward] clever 3D models to explain the requisite tooth shape !

MichaelG.

[Oily RagParticipant @oilyrag]

That looks to me like a spur gear with a slight helix angle to mate closely to the leadscrew (picture posted by Rob). A cheaper way of mating what is a 'worm' (leadscrew) with a right angle driven system, than producing a wormwheel. The gear can be cut in the normal way by a hob or simply by a B&S type form cutter by angling the component by the value of the lead angle.

The apron gears on my Raglan are formed this way which mates with the power feed worm wheel, meanwhile the rack and pinion for the hand drive of the saddle is a normal 'zero offset' spur gear as the rack's lead is equal to the pitch.

So, in conclusion I think Bob's problem is that the gear has been 'over engaged' in the past and the root of the leadscrew thread has worn the tips of the pinion gears. Maybe the original pinion gears were straight cut, which on a closer look at his photograph there is a suggestion this is the case) – in which case the wear will be more concentrated as the pinion gear flanks will be single 'point' loaded rather than having a slightly lower stress level with a 'lead angle' pinion gear matching the appropriate lead angle of the leadscrew.

Martin

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