Ml4 broken bull wheel problem.

[Martin King 2Participant @martinking2]

Hi All,

Just got an ML4 in overall good order but absolutely filthy! Have stripped it all down and am slowly cleaning and checking all the bits. Main problems so far are the eve pulley which has three quite bad lumps out of it, but have found one on eBay which is on its way.

More of a hassle is the main bull wheel 65 teeth 1" bore with a grub screw to lock to the spindle. This has two teeth missing in one place and another in a different place!

I do have a couple of spare 65 tooth change wheels for my ML7. These are slightly narrower in width and of course different bore, the pitch seems the same by eye.

Any suggestions as to whether I can do something with one of these as finding a replacement is not looking good? Does not seem to be much room for a grub screw if I open out the bore?

Regards, Martin

[Martin King 2Participant @martinking2]

[peak4Participant @peak4]

Maybe use your 65 tooth gear off the ML7 as a dividing pattern, with a suitable detent, and cut a replacement from a slice of cast iron?

[Ady1Participant @ady1]

If it's going to end up trashed then maybe try to build up the broken part with spot welding?

Then file to shape

Practice on some scrap cast iron first

Lidl do a 40quid welding kit, I suppose Aldi does that sort of thing intermittently too

Edited By Ady1 on 19/02/2016 17:39:54

[Martin King 2Participant @martinking2]

When ever I have had cast iron welded the weld is incredibly hartd, a file will not touch it .

Martin

[HacksawParticipant @hacksaw]

Drill a row of holes where a tooth should be , tap them and loctite in some studs . File the exposed row of studs to the tooth profile .. move on to the next missing tooth….?

 

http://home.iprimus.com.au/stevor/gearrepairs.htm

Edited By Hacksaw on 19/02/2016 18:19:23

[JohnFParticipant @johnf59703]

Martin, it can be welded but you need to use the correct welding rods and it must be preheated beforehand , you will also need to anneal it in muffle furnace afterwards so you can machine it.

Alternatively make a suitable cutout and silver solder a mild steel insert then re-machine the teeth. I once repaired an ML7 bull wheel by this method

Where are you located ? Nothing on your profile ?

John

[Martin King 2Participant @martinking2]

Profile added

[julian atkinsParticipant @julianatkins58923]

the clock repairers' method for replacing a few broken teeth might be applicable albeit via a cast iron insert loctited in position suitably filed up.

cheers,

julian

[AjohnwParticipant @ajohnw51620]

Hacksaw mentioned the usual way of doing it simply. When I used the rack feed on a Raglan to slot a bore 2 failed after the last cut. They pegs were silver steel, 2 across the gear. The ones that were left meshed well suggesting that they had been cut properly. It was a fairly coarse gear.

The other way is to slot and fit and fix a piece of metal in and recut the tooth. Don't let it cool too quickly if the piece is braised in.

Personally as you have a gear with the correct tooth count best make a new gear.

John

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[Dave HalfordParticipant @davehalford22513]

Posted by Martin King 2 on 19/02/2016 17:57:20:

When ever I have had cast iron welded the weld is incredibly hartd, a file will not touch it .

Martin

Um, yeah I've been that stupid too. If the rods have got any FE in them that happens.

What you need is pure nickel rods, needless to say these are the expensive ones, and you can machine nickel

[Martin King 2Participant @martinking2]

Hi All,

Sourcing one of these bull wheels is proving very difficult if not impossible.

I do not have the heat source to get this to hot enough for brazing and the 3 local shops I have been to will either not touch it or want around £100 to 'maybe' do it!

I also have virtually no experience at welding or brazing let alone cutting gear teeth.

The answer I seem to have come up with is to try and use one of the spare 65 tooth change wheels, bore it out a bit larger than the 1" needed and then make a brass or bronze bush to fit that is thick enough to allow a grub screw to be drilled and threaded to fix to the spindle. Perhaps secure with Loctite or put the bush in freezer before fitting? Maybe pin it to the gear?

I realise that the change wheel is slightly narrower than the original but hopefully will be OK.

Does anyone have any reason on why not to go this route or any other suggestions or advice please.

This will be quite a test for my level of experience so could turn out OK or end up in the bin!

Cheers, Martin

[AjohnwParticipant @ajohnw51620]

John Ward might make you one. His rates are usually very reasonable and his work is very good. Biggest problem usually is getting hold of him.

John

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[Neil WyattModerator @neilwyatt]

> I do not have the heat source to get this to hot enough for brazing and the 3 local shops I have been to will either not touch it or want around £100 to 'maybe' do it!

Sounds like an excuse to get an inexpensive propane torch kit from Machine Mart. Look how much I have saved dear!

Neil

[Martin King 2Participant @martinking2]

Does this mean that brazing is the only way to go? Does my idea of a sleeve have any merit at all?

Martin

[Brian WoodParticipant @brianwood45127]

Hello Martin,

I have had success with brazed repairs on cast iron gear wheels using oxy acetylene and would be happy to restore this wheel for you if you so wish. I fitted peg teeth to my old ML4 wheel many years ago, long before I had those facilities, but full tooth replacement is a lot stronger.

I live in North Yorkshire, but postal services will do just fine for this. Send me a PM if you want to take this further. Your only other avenue is to find another ML 4 lathe being broken for spares

Regards

Brian

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Martin King 2 on 25/02/2016 10:22:37:

Does this mean that brazing is the only way to go? Does my idea of a sleeve have any merit at all?

Martin

.

Martin,

I would say that your idea has a great deal of merit … provided that the tooth profiles really do match [your original description was a little sketchy] … Measure; Check; and Check Again before you re-work what might be a saleable ML7 item.

MichaelG.

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