Myford dividing head body casting material

[Anthony KnightsParticipant @anthonyknights16741]

Posted by samuel heywood on 19/01/2023 01:38:59:

Worked pretty well actually~ all Heath Robinson with a car battery charger,

I forget what the solution was, but bound to be out there on the interweb.

For electrolytic de-rusting, washing soda solution is usually recommended. Cheap and relatively harmless.

[HopperParticipant @hopper]

Well a big surprise and a definite turnaround for the books this morning. After leaving the vertical slide soaking in my parts washer tank overnight, with a very minimal bit of scrubbing with a small wire brush, most of the "rust" has disappeared. It seems most of it was a thick hard layer of congealed oil/grease mixed with dirt. These bits came from out in the red dirt farming country, where the soil gets its colour from the iron oxide/iron ore it contains. So I am guessing they were well oiled up a million years ago and then left out in the open in the typical farmer's open sided shed with (red) dirt floor and the dust blowing in 24/7.

It came up looking a treat. 95 per cent clean metal after the gunge was gone. So a minor polish up with some Scotchbrite and steel wool and it will be almost as good as new. Woohoo!

The dividing head looks to be in similar shape. It is taking a bath in the parts washer tank tonight. It has some rust etching on the index plate but the rest is not too bad. The tailstock overarm is rusted, as is the spindle register. But I got the spindle to turn, sluggishly so left it to soak. The parts washer fluid is probably a good penetrating oil, being a mix of degreasing solvent and the old oil washed off many previous engine and lathe parts. It is some nasty stuff. But I am so glad I bought these bits now. Definitely much better than they looked.

And I reckon I can make an adaptor to use my GH Thomas dividing head's indexing plates on this dividing head as the hole in the middle of the GHT version is bigger than the Myford one, so an adaptor could be made I reckon. Save me from drilling another 800 holes to make the 3 missing plates. Both are 60T worm wheels so the hole circles will relate.

[Kiwi BlokeParticipant @kiwibloke62605]

Posted by Bazyle on 18/01/2023 20:14:20:

The molasses method is not worth the effort and is very hit an miss. It only works at all because of fermenting sugars turning to alcohol then oxidising to acid. Apart from the bit with mazak you might try electrolysis.

No, this is not true. Molasses contains chelating agents, and it is chelation that removes the rust. It works before the stuff has a chance to ferment (if you're reasonably hygienic). If it were alcohol acting as a reducing agent, booze would work. The problem with molasses is that it's slow, but in Australia, in summer, it'll only take a fortnight to deal with significant rust. Evaporust works well, but is expensive. That's also thought to be a chelator – perhaps EDTA.

Great news, Hopper! Everyone deserves some luck, some time! Bet you're as pleased as a dog with two er, …..

[SillyOldDufferModerator @sillyoldduffer]

My experience of restoring rusty machinery is very limited, and I hope others will weigh in!

I'd be wary of starting by doing anything dramatic like electrolytic rust removal because although it works well on Ferrous metals, it eats Aluminium, Zinc and Mazak, and may corrode Brass or Bronze enough to cause noticeable wear and tear.

I think I'd start by soaking the dividing head for a few days or longer in a light oil. Penetrating oil would be best, but petrol or even diesel would work. ISO32 is a bit thick for this, but it would eventually do the job. Some recommend a mix of Hydraulic Fluid and Acetone, never tried it, but it's a sensible combination – the acetone would penetrate, and carry oil inside with it.

After a good soak, remove any loose muck and corrosion and – without forcing – dismantle anything that comes apart. The individual parts can be cleaned separately, for example the Brass fingers will respond to Vinegar.

If anything is still stuck, and obvious that heat will do no damage, warm and cool the item (or stuck bit) several times with a blowlamp. Too hot to touch, not red-heat! This causes the metal to expand and contract, breaking up rust and gummed oil. May come apart at this stage, otherwise a second long soak will allow oil to penetrate deeper into the mechanism, and loosen everything up step by step. Heat cycling and brute strength is probably the quickest way to unstick corroded parts, but also more likely to cause damage. Soaking takes longer, but is unlikely to break anything. A combination of moderate heating and long soaking will get there in the end, but bear in mind it can take a very long time for oil to penetrate deep into a tight space packed with rust.

Commercial penetrating oils are faster that home-made because they contain a calculated mix of thin and thicker oils designed to dissolve gummed oil and wick into tiny gaps. They also, usually, contain chemicals that attack rust, breaking it into fragments and so the mix penetrates deeper and faster. The main advantage of home-made potions is their cheapness and availability. Molasses has been mentioned, but beware! It's one of those loose lay words that describes several rather different substances. The variant best at rust removal is the rough unrefined type available to farmers as a cheap animal-feed. Makes good sense to use it on a farm. The expensive human food-grade Molasses sold in British food shops is far less effective on rust, I wouldn't bother.

Once components are removed, they can be physically and chemically cleaned using an appropriate method. The main cast-iron body could be brutally wire-brushed and electrolytically cleaned without concern, whilst delicates like gib-strips, worms, screws and bearings should approached much more carefully; fine steel wool, toothbrushes, metal polish etc.

Dave

PS and I see in the time I took to type this, Hopper has already done it!  A good soak revealed his dividing head isn't corroded or gummed at all.  Result!!!

 

Edited By SillyOldDuffer on 19/01/2023 10:07:32

[Michael GilliganParticipant @michaelgilligan61133]

Great progress, Hopper

… must be good Karma from some kindness you have done someone !

MichaelG.

[HopperParticipant @hopper]

Posted by Michael Gilligan on 19/01/2023 10:02:24:

Great progress, Hopper

… must be good Karma from some kindness you have done someone !

MichaelG.

Must be. Can't think of what or when it was though! But every dog has his day. Sure was my lucky one yesterday. Looking at the prices for nice condition Myford dividing heads I almost feel embarrassed. Almost.

I'll be watching this rusty one on eBay UK with interest:

LINK

Edited By Hopper on 19/01/2023 10:38:50

[BazyleParticipant @bazyle]

Coincidence or someone reading this thread but a rusty one appeared on ebay uk last night.

[HopperParticipant @hopper]

Out of the soup and into the daylight. And the dividing head looks pretty good too. Not as pristine as the vertical slide but amazingly good considering how it looked on the surface. Most important, the msomain spindle and worm and worm wheel are all good. Bit of rust on the spindle nose but fixable.

I got some Evaporust at a more reasonable price so I have the tailstock overarm soaking in it overnight, and the index plate. As I bought only 1 litre ($25) there is not enough to fill a soaking bath so I slathered it on the overarm bar and put it in a plastic bag rolled up so it can soak in that overnight. The index plate I just brushed some on and left it sit there. So will see tomorrow how they compare.

[HopperParticipant @hopper]

Posted by Bazyle on 19/01/2023 10:50:07:

Coincidence or someone reading this thread but a rusty one appeared on ebay uk last night.

Still sitting at 87 Quid. But 5 days to go. It's the last 5 seconds that count. Watching with interest still.

[John HaineParticipant @johnhaine32865]

Well this thread should bump it up! By the way, don't expect the spindle to turn freely, it should be adjusted on the outer clamps to be a bit stiff and use the centre one to lock it.

[noel shelleyParticipant @noelshelley55608]

I told you it was a good buy at 100 of our sterling pounds ! Great to get a bargain ! Noel.

[HopperParticipant @hopper]

Posted by noel shelley on 20/01/2023 10:40:33:

I told you it was a good buy at 100 of our sterling pounds ! Great to get a bargain ! Noel.

Yes indeed. About time. I am always envious of the treasures you guys seem to come up with at UK boot sales and all I get are some old cane farmers' toolbox with the bottom rusted out full of spanners in same condition. This one is definitely a turnaround for the books. And i just looked on eBay at what vertical slides sell for now. Goodness. I think I paid 70 quid for mine not many years ago and had it shipped to Australia. They have doubled and more since then. So I could get my money back on that one alone, plus change.

[HopperParticipant @hopper]

Posted by John Haine on 20/01/2023 09:58:21:

Well this thread should bump it up! By the way, don't expect the spindle to turn freely, it should be adjusted on the outer clamps to be a bit stiff and use the centre one to lock it.

Thanks for the tip. I have downloaded the Myfrod instructions/ manual but have not read it yet. I did notice there is red fibre gasket material in the slots where the pinch bolts clamp both the spindle and the tailstock overarm. I guess that is so you can't over tighten the clamps?

[John HaineParticipant @johnhaine32865]

Yes.

[HopperParticipant @hopper]

Well I am undecided on the Evaporust so far. Having only 1 litre I could not really immerse things in it overnight,and it seems to evaporate away if just brushed on and left sitting out. So I hatched a cunning plan and brushed some on the index plate and the overarm then put each one in a plastic bag with a glug (technical term) of extra Evaporust so the parts would stay immersed overnight, sort of. But every plastic bag seemed to have a hole in it and it ended up the sections that were on the bottom in what was left of the liquid derusted OK-ish but the top bits above the tidemark not so much.

Please let me know if you can't see the picture. I am experimenting with using Imgur pic hosting and it is a bit experimental at this stage.

But still looking way better than when it lobbed on my doorstep seeking succour.

So I doused various other bits today and wrapped them in plastic bags today. Checking progress just after dinner, the spindle nose has come up nice and rust free, but a matt silver finish all over that will still need a final polishon the wire buffing wheel.

So I am not totally convinced that the process is any less faff than my usual wire buffing wheel on the 8" bench grinder outside. Advantage may be that with things like the spindle nose register and overarm, the rust is offed with out removing any unnecessary parent metal, thus maintaining dimensional integrity as much as possible. I could have just spun the overarm in the lathe and emery-clothed it, but that would take a thou or two off the diameter and affect the alignment by that tiny and possibly not critical amount. But still, nice to keep it to factory specs if possible on precision parts. I think a very light buff on the wire wheel to finish it up will not make a measureable difference. (Not measureable with my shaky hands and dodgy eyesight anyway!)

Will see how it shapes up in the morning and report back.

ONe thing I did learn is don't use black plastic garbage sacks for this process. They make black stains on the job, which hopefully the Evaporust will have removed by morning since I discarded the black bag.

 

 

 

 

Edited By Hopper on 21/01/2023 10:27:12

Edited By Hopper on 21/01/2023 10:27:57

Edited By Hopper on 21/01/2023 10:35:53

[John HaineParticipant @johnhaine32865]

If the worst comes to the worst you could replace the overarm with a chunk of silver steel – I think it's a standard diameter?

[HopperParticipant @hopper]

Posted by John Haine on 21/01/2023 11:27:01:

If the worst comes to the worst you could replace the overarm with a chunk of silver steel – I think it's a standard diameter?

Yes. I haven't measured it but it looks like 1" bar. I think it will come up useable though. Good enough for what I am likely to use it for. According to Myford it is not for mounting jobs between centres but on a stub mandrel held in collets at one end and the tailstock centre just lending a bit of extra support at the other.

[HopperParticipant @hopper]

An interesting aside on the Myford dividing head. GH Thomas has a chapter on it with a few good tips, of course, in Workshop Techniques. But I did notice that while the Myford DH uses a total of four indexing plates with 7 or 8 hole circles in each, the GH Thomas Versatile DH achieves the same result with only three much smaller plates with far fewer circles and smaller numbers of holes. Still gives every division up to 100 and many more beyond, including the mystical 127. So, according to Occam's Razor, old GHT's solution is the most elegant. Cunning old dog he was. Left the men at Myford in the shade.

So I can make up an adaptor ring and just use my set of VDH indexing plates on the Myford unit and use GHT's charts. Brilliant! No need to cut out discs and drill 800 or more tiny holes!

[Martin KyteParticipant @martinkyte99762]

Posted by Hopper on 21/01/2023 11:47:06:

Posted by John Haine on 21/01/2023 11:27:01:

If the worst comes to the worst you could replace the overarm with a chunk of silver steel – I think it's a standard diameter?

Yes. I haven't measured it but it looks like 1" bar. I think it will come up useable though. Good enough for what I am likely to use it for. According to Myford it is not for mounting jobs between centres but on a stub mandrel held in collets at one end and the tailstock centre just lending a bit of extra support at the other.

If you do replace the overarm precision ground mild steel would be a cheaper option at 1” dia

regards Martin

[HopperParticipant @hopper]

Posted by Martin Kyte on 21/01/2023 12:20:26:

Posted by Hopper on 21/01/2023 11:47:06:

Posted by John Haine on 21/01/2023 11:27:01:

If the worst comes to the worst you could replace the overarm with a chunk of silver steel – I think it's a standard diameter?

Yes. I haven't measured it but it looks like 1" bar. I think it will come up useable though. Good enough for what I am likely to use it for. According to Myford it is not for mounting jobs between centres but on a stub mandrel held in collets at one end and the tailstock centre just lending a bit of extra support at the other.

If you do replace the overarm precision ground mild steel would be a cheaper option at 1” dia

regards Martin

Yes, just looking at that on eBay Australia. Quite reasonable, shipped in from India. But of course 1" is out of stock at the moment! And silver steel would gradually get whittled down to make special cutters etc. "Just a little bit more."

[duncan webster 1Participant @duncanwebster1]

You might drop lucky and find a scrap hydraulic ram. Chrome plated and ground

[noel shelleyParticipant @noelshelley55608]

Good one Duncan ! If Hopper was closer I would give him some, a common size on old cylinders ! Noel.

[HopperParticipant @hopper]

Yes good idea. Plenty of tractor workshops around here so might find a bit. I will find out this morning how the original shapes up when I pull it out of the Evaporust. I think it will be good enough to be going on with. Will see.

[John HaineParticipant @johnhaine32865]

Posted by Martin Kyte on 21/01/2023 12:20:26:

….

If you do replace the overarm precision ground mild steel would be a cheaper option at 1” dia

regards Martin

Provided that it's actually round and not like the length I bought some years back. The centreless grinding machine had given it a distinct "lobed" shape like the rotor of a Wankel engine. Measured at 1" diameter but as I was trying to make an air bearing…

[HopperParticipant @hopper]

Posted by John Haine on 21/01/2023 22:26:14:

Posted by Martin Kyte on 21/01/2023 12:20:26:

….

If you do replace the overarm precision ground mild steel would be a cheaper option at 1” dia

regards Martin

Provided that it's actually round and not like the length I bought some years back. The centreless grinding machine had given it a distinct "lobed" shape like the rotor of a Wankel engine. Measured at 1" diameter but as I was trying to make an air bearing…

Yes i think I will stick with the original British made overarm, warts and all, but at least it is round. And see following pics, it has come up pretty good after the Evaporust treatment. Cheap Chinese and Indian junk is the bane of my existence. Old bike parts that fail are pretty much the norm, not the exception. Just fitted an allegedly Taiwanese made folding kickstarter to one of my Harleys and it bent on the third kick. Very obviously a malleable casting, not a drop forged alloy steel unit like the HD original, which was indestuctable and you could bet your life on it, let alone your right knee joint.

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