Member postings for Don Cox

As mentioned above, a light touch with a thread file might clean off any "bruising" present, it has worked okay for me on my Myford ML7. I have three, metric, BSW/BSF and UNF/UNC and have used them to clean damaged automotive threads and others over the years.

Don Cox

With regard to introducing a spark gap into HT leads, When trying to make the transition from one time telephone "engineer" to FE lecturer in Motor Vehicle technology I was once told by a colleague ( who was a real motor engineer as opposed to an enthusiastic amateur like myself) that carbon string HT leads performed better than solid copper ones because their resistance was too high to pass the initial current until the output voltage of the coil had risen sufficiently to close to its maximum. This had the effect of not wasting energy in the initial phase of the ignition sequence, only releasing it when it was really useful to contribute to making the arc.

Nowadays, coil on a plug is the norm (so far as I know) so the HT path is only about 150mm long on the DOHC engines which seem to be prevalent these days. At the time of our discussion, ignition systems with CB, Hall effect and inductive sensor triggering systems were still commonplace and most engines still had a mechanical distributor. There were a few with centralised coils with ignition leads sprouting from them and the coil on a plug type was becoming ever more the norm.

Within the next 15 years, or possibly sooner, I expect all of this discussion will be consigned into the darker corners of history, a bit like steam technology mostly is today!

Good for giving a suntan, make sure that all exposed skin is kept to a minimum, obviously appropriate eye protection needed too.

More favourable siting of the base station might improve things. Installing it in an upstairs room closer to the workshop for instance might work. Access to the 'phone line and mains power might limit this option although there may be some currently redundant 'phone cabling which might allow extending the line from the incoming point to the more favourable base station site.

After 15 years in my retirement job in the Motor Vehicle department of our local FE college where I had free and unlimited access to tyre fitting, wheel balancing and many other vehicle facilities, I finally retired and had to buy tyres fitted as part of the deal like everybody else. I bought them online from a well known national supplier and as part of the spiel on the day I was asked if I wanted a Nitrogen fill at extra cost. After explaining that I knew a bit about tyre fitting and expressing doubt that nitrogen would give any real benefit, I asked how it was possible to displace the existing air from the tyre when it was being pressurised and what percentage of oxygen it was expected would remain compared to the 20% that was normally present in air. All I got was a load of waffle and no satisfactory explanation. I doubt that they bother flogging that particular dead horse now either.

Myford Ltd website also has what appears to be a full record of serial numbers. To be a Tri leva it has to be an ML7 ( beware that the Tri leva bits may have been added at a later date) you might be able to read the number again with a more enlightened view to try and make it fit into the ranges published there

I built an Ikea Helmer drawer cabinet under my radial arm drill. Okay for £35 I thought, although I paid for delivery because visiting the store drives me nuts.

Andrew’s recent post about telephone exchange maintainers and their dogs, and later Peter Shaw’s account of his dalliance with what I suspect was a UAX13 type exchange remind me of my own experiences. I joined PO telephones in 1963 and left B.T. in 1996, I spent the majority of my time with them maintaining exchanges, with a a significant period of that time looking after some smaller, rural ones, UAX 13, 14s and later TXE2s on my own (although I did take our black Labrador to work on occasions).

Whilst we were very well trained to be able to locate and repair faults in the switching equipment, most of us had only a sketchy idea about the power plant and relied on the expertise of the “power group’ to deal with any significant problems.

The power system in place in the exchanges when I first started work in them was to have two batteries, one charging and the other “floating” the exchange with, if I recall correctly, a nominal 24 hour turnabout. The problem with this system was that the battery just about to be switched in to run the exchange was significantly, often two or three volts, over the nominal 50 volts that the exchange required. To deal with this a battery of “counter emf” cells were wired in series with the main battery, these were alkaline cells with a nominal voltage of 1.1 volts, connected in reverse polarity and they were short circuited by the switch gear only being brought into use by removing the short when the battery voltage was too high. As you might imagine, these batteries objected quite violently to this treatment and used to “boil” when in use, so much so that a layer of oil was sitting on top of the electrolyte to prevent frothing. As exchanges grew bigger the power demand increased and bigger main batteries were installed, although the counter emf cells remained unchanged. This resulted in even more violent boiling and the oil layer was replaced by plastic “pebbles” to try and collapse the froth that built up. The switchgear to achieve the control of this system usually consisted of some chunky copper “shoes” moved into and out of position by a worm drive.

Much to the relief of everyone involved, improved power plant design did away with all of this and a system known as “end cell switching was installed in all of the exchanges I looked after. This had a battery kept fully charged by a rectifier which followed the load demanded by the exchange and regulated the voltage to close limits of the required 50 volts. If a mains power failure occurred, then the “end cell” which was isolated from the main battery and separately charged by another rectifier, was switched in to replace the high level of charge initially existing as the main battery moved away from the highest point of the discharge curve. After that, if there was an engine driven generator installed that should take over, if not then a “phone call to the “power group” would get you a portable generator to connect to.

Adding to the slightly off topic content of this thread, I would suggest a better use of copper based grease on car wheels is to smear it lightly onto the spigot where the wheel centres onto the hub. This is particularly important with alloy wheels. I leave the wheel nuts clean and dry.

Tom

Mine's a 1949 one. I suggest you start by getting some Nuto H32 oil and squirt it into the headstock and countershaft bearings. The headstock bearings seem to live for ever so long as the are kept lubricated, so fingers crossed. Also oil the slideway surfaces and anything else that moves, or is tarnished, with it, a few drops in the motor bearings would be good too. Then start removing the grime to see what you've got. The 1997 manual will give quite a bit of info as will the Myford website. There's more knowledge relating to these lathes here than anywhere else I've seen.

Good Luck

Don Cox

For what its worth I bought an ML7 (1949) about 15 years ago, it was intact but quite scruffy and had only a 3 jaw chuck, I paid £450 for it. About 5 years ago I bought an S7 (1964) with a gearbox and on a Myford stand, the one with the Hexagonal ends, I paid £950 for it and I still have both it and the ML7. The ML 7 turned out to be in an overall quite good condition and after mounting it on my own scratch built replica Myford stand ,with some in-depth cleaning and a few coats of paint it still looks and performs well.

I regularly patrol the eBay "Myford" offerings and have come to conclude that ML7 prices have apparently stepped up to get quite close to S7 prices, when I bought my ML7 it was about half the equivalent S7 price, Your pictures appear to show that the one you're thinking about has a Hoover motor (so probably original, mine has too and after a bit of cleaning up internal workings and remaking the connections it still performs like it should). The pictures don't show the end, belt and gear, covers. are they still with it? My main concerns about inspecting the condition of the lathe would be the main the bearings (stick a long bar in the chuck and see how much you can deflect it side to side/up and down) and the state of the bed surfaces (visual inspection, hacksaw marks and how much movement is there in the cross slide near the chuck and how tight is it near the tailstock?).

Good luck with your purchase if you decide to go ahead.

Edited By Don Cox on 21/02/2021 09:36:46

Edited By Don Cox on 21/02/2021 09:39:45

I too worked for Post Office telephones starting as a "Youth in Training." After a couple of enjoyable years charging about in a dark green Mini Van fixing customer's faults I was taken on as an exchange maintainer working on Strowger (clock work) equipment.

The contact array, which two motion selectors stepped over to make the forward connection, consisted of 11 contacts arranged in a semi-circle, stacked 20 high with plastic separators insulating adjacent contacts, these were known as "banks". Occasionally we would get a contact fault between contacts and since these banks were usually connected in multiples of 20 ( on two shelves of equipment) finding which bank unit was involved was quite a task. One of the old hands told me that these faults were usually caused by wayward bits of solder etc left behind during manufacture and that actually taking the trouble to locate the cause took up too much time and effort. The standard method to clear the fault was to apply the exchange 50 volt DC supply either side of the fault protected with the smallest fuse possible (0.25 Amps I think). Nine times out of ten this cleared the fault with no recurrence and didn't blow the fuse. The one in ten which persisted involve a lot more work, but that's another story. I have used this technique quite a few times to clear car electrical faults over the years too.

I've long thought that electric smart meters will only be of real benefit if we have them paired, and able to communicate with, smart appliances, eg washing machines, dishwashers, electric car charging systems etc so as to make use of the lowest price energy when it is available. I've not seen any progress towards that....yet.

Google "valve spout oiler" I have two for 32 & 68 grade oil which work well on both the the "flush" and grease nipple type oilers as fitted to Myfords.

After many years of buying tyres on line and fitting and balancing them myself at the College where I worked, following my retirement I had to buy some tyres with fitting included. Surprisingly Kwik Fit came out as a good deal when pre-ordered.

When I took the car in having nitrogen fill was offered as an extra by the guy at the desk, he was a bit nonplussed when I asked him to explain how all the air could be displaced from inside the tyre by Nitrogen squirted through the valve, he didn't have an answer. Personally I think Nitrogen fill ranks with engine flush and fuel cleaner offered at routine services, a nice little earner for the garage, but totally unnecessary.

My Dad ran his own Electrical contracting business from just before WW2 until retirement in around1975, he used Rawlplug Jumpers for lots of his jobs. He also bored holes in floor joists with a brace and auger bit and did lots of other manual work with hand tools. I remember him watching me using my first cordless combination drill in about 1995 and could see him thinking how much easier life could have been for him if they'd been about a few years earlier.

My father was a sparky from the age of 14 and was born in 1909, he used to tell of being sent from his home town Bath to London when in his early 20s and of being told by his boss to pick up the IEE (or equivalent then) wiring regs which were at that time about 15 pages long. He stayed in the industry all of his working life. Many years later, as part of my transition from 33 years with BT as a telephone "engineer" I took and passed the IEE 16th editions wiring qualification, my (paperback) book was about 3/4" thick.
My understanding of domestic voltage choice, now 230v, was that it was the highest which was still reasonably safe to have in that environment. The continentals double pole switch all of their devices because they can't rely on maintaining live/neutral polarity , nowadays all socket and lighting circuits are RCD protected and virtually all appliances are double insulated with very few metal bodied , class one, devices about. All of my domestic circuits are RCBO protected.

My IEE code of practice for in service inspection and testing of electrical equipment.manual (PAT testers's bible) has it that there are only two plug top fuse ratings 3A an 13A to be fitted to protect over 0.5 and 1.25 square mm cable. On the course I did we were told the fuses are fitted to protect the cable, further protection of, lower rated, individual parts of the appliance should be by internally fitted fuses.

Edited By Don Cox on 24/03/2020 11:50:14

I don't know if it's the same stuff, but Hot Tubs use it in powder, or in tablet, form as a disinfectant, I would have thought an owner of such would be prepared to donate you some.

Don

My 1949 ML7 came without a clutch and was fitted with a 1/3 hp (I think) Hoover motor which I believe to be the original one fitted from new. The lathe was quite tatty when I collected it (cost was £450) but it had no insurmountable problems when I came to pull it apart. I rewired the motor switch set up, it now has an NVR wall mounted switch and a Dewhurst forward,/stop/ reverse switch mounted behind the front face of my home made copy of a Myford hexagonal stand.

I've had it for about 12 years now and have never noticed the motor to be over heated, I frequently use the belt tensioner as a clutch to limit the number of start ups and the Dewhurst switch stays permanently switched to forward.

I bought a Tri-Leva conversion to go on it a few years back, but I then chanced across an S7 (1963) on eBay, with a genuine hexagonal stand, a gearbox and close to home, for £950. So now the Tri-Leva bits remain unused in their box and the ML7 does a bit less than it used to. The S7 now has a VFD motor setup and, of course, it came with a clutch. I tend to use the lathes in turn to avoid having to change tool holders, chucks etc for different jobs, I don't find not having a clutch on the ML7 a major disadvantage.