Myford dividing head body casting material

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.

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!

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."

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

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

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.

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.

Anyhoo, got to the end of the Evaporust treatment today and all is good. The main spindle came up beautiful, ditto the index plate, the vertical slide table and all other bits. Very impressed. A light wire brushing (hand, not wheel) and it looks good. There is some etching visible on the overarm but the rust is gone and the parent metal preserved so functionally it will be all good, sitting on the original OD. If I had emery clothed it down in the lathe, the bar would have come down to the diamter of the bottoms of the pits. This way the original OD is preserved.

Compare and contrast that last image with this "before" shot:

Pretty much says it all. Very pleased with that result. Very pleased indeed.

Now for the part of restoration I enjoy the least: painting. In 32C with 85pc humidity it can be a real challenge, as I am sure it is for you guys in mid-winter. Paint will sit there and just look at you and refuse to dry for day after day after day. But I have my secret weapon now: air conditioning in the shed which knocks humidity down to a sensible, paint-drying 50pc. I have some leftover grey machinery paint from when I did the ML7 so will brush a bit of that on all these fiddly bits. Should dress it up nicely to match the shiny new metal finish.

Onward through the fog!

PS: ONe thing I did learn is that as you use the Evaporust overnight etc, it turns black from the particles of converted (or whatever) rust floating around in it. This tends to leave black stains on the pristine new surface of the job. particularly around the waterline on partly submerged parts. They can be removed with a wire brush, but much easier to wash down with fresh Evaporust and it gets rid of it. A final brush down with fresh Evaporust gives a nice final finish, a matt surface that brightens up with a quick manual wire brushing. Very nice. I used about three quarters of my 1 litre of Evaporust on this job. For anything thing bigger I would buy the 5 litre pack and use it in a lidded container to stop evaporation.

Edited By Hopper on 22/01/2023 10:35:40

Edited By Hopper on 22/01/2023 10:41:09

Edited By Hopper on 22/01/2023 10:42:03

Edited By Hopper on 22/01/2023 10:42:23

Well I think you got yourself a bargain there Hopper!

Geez, I reckon, hey. Will come up looking like a million bucks with a lick of paint. I could, if I wanted, sell the vertical slide for more than I paid for the whole lot. Free dividing head. Very pleased with that.

Really pleased this has worked out well, nice when someone gets a useful bargain, has cleaned up remarkably well.

I was a bit unsure about the Evaporust when first using it, but found pretty much the same as you that some neat solution would remove the black from the pits. As mentioned in previous post my mate who restores vintage cars swears by it, and some of the bits he restores to usefulness from rusty lumps astonish me.

Look forward to seeing the finished article, I hate painting too!

Dave

Thanks Dave. Yes it has worked out well, for a change. Busy with the Harton Snortster project but imagine I will get time to dab some paint on on the dividing head etc this week.

It’s up to £112 now and there’s still 3 days to go!

Well, I am already ahead of the game then! By 12 Quid and a vertical slide. Will be interesting to see if there are any "snipes" in the final minute or two. Can make a huge difference if there are two or three of them competing.

A little more progress today with painting all the little bits and pieces. Did it with some leftover machinery paint from when I did the lathe, applied with a small artists brush. Less faff than masking up and spraying and quite therapeutic to sit and brush paint. Took me back to toy soldier days. It is not quite Myford grey but a shade darker, being RAL 7011. But close enough for bush work. No Paragon paints etc available here and they won't ship it in. At the end of the day, it is a piece of workshop equipment, not a Rolls Royce Phaeton.

Next job is to make the one missing clamping disc from the lower swivel. Just a piece of 2" diameter steel bar sliced about 1/4" thick, faced and two holes drilled in it for the T bolts. I could part it off a bar in the lathe with the fixed steady. I have done it before on the old Drummond but it is never a relaxing job, so will do it the modern way and slice the bar on my cheap Chinese horizontal bandsaw and then face it off in the lathe. Much less stress. Then oil blacken it.

The other thing is I noticed the dividing head spindle will not screw into my four jaw chuck at all and is very tight in the faceplate. Not sure if the Evaporust has left a small layer of residue on the metal and made it tight, or if the spindle nose thread has a slight bruise on it. So some very careful massaging with a wire brush and perhaps a thread file may be called for.

Edited By Hopper on 25/01/2023 07:30:34

Edited By Hopper on 25/01/2023 07:31:50

Hi Hopper

Dividing head went for £155.01, looks like you got a bargain, happy days

Yes I reckon I did quite nicely thank you very much. Still, not a bad deal for the eBay buyer either when you see the prices being asked for some dividing heads in good shape with two index plates. Almost 500 Quid by some dealers. That eBay one included the GH Thomas-style raising block and offset clamping bolt plus the collet and bar so not a bad pile. I wonder if his will be as easy to de-rust as mine was though? I am still amazed at how bad it looked and how well it has come up.

Paint finally dried enough for reassembly. Only took 3 days in the current 85pc humidity. Gotta love the tropics. But it came up looking a million bucks. Chalk and cheese with the original state. One thing I found was that the main spindle where it fits in the bore in the dividing head housing, and where it fits in the chuck register, were both very tight. A light dressing down with very fine emery paper in the lathe was needed to get a neat sliding fit as required. I can only conclude that the Evaporust perhaps leaves a thin layer of some kind of deposit on the parent metal. Maybe half a thou thick or so. The spindle surface that runs inside the dividing head body was shiny before Evaporust immersion, and came out matte, so more likely a deposit of some sort rather than any kind of etching. But, all back together and ready to use in anger. Now I need to get started on that working model Harley engine and the 14 gears in the timing chest it needs.

Edited By Hopper on 28/01/2023 08:21:57