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Member postings for Don Cox

Here is a list of all the postings Don Cox has made in our forums. Click on a thread name to jump to the thread.

Thread: BANG!
23/11/2020 23:34:59

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.

Thread: Electric Smart Meters
13/10/2020 10:14:34

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.

Thread: Need to know about iPad 'air'
25/06/2020 23:14:04

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.

Thread: Can summer car tyres be used in winter?
17/06/2020 08:05:08

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.

Thread: Look what I Found
19/05/2020 23:36:16

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.

Thread: New design of mains plug?
30/03/2020 23:35:01

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.

Thread: Fixing motor for Myford Ml7
24/03/2020 11:48:32

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

Thread: Where to acquire a small amount of bromine
06/02/2020 14:33:57

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.


Thread: Myford ML7 clutch
12/01/2020 08:54:23

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.

Thread: Myford super 7 oiling
05/01/2020 09:06:16

We've walked this path before a few times. My solution has been to use "Valvespout" oilers, one for each type of oil (H32 and K68). They have a small nozzle fitted, similar in proportions to John Purdy's photos above, which will trip the balls in both the "grease nipple" type oil points and the flush to surface type ones on older Myford lathes, off of their seats to allow oil to enter with virtually no spillage. Have a look here:

Thread: ML7 Countershaft
25/11/2019 13:57:54

Mine's 0.75" measured on the open piece of shaft to the right of the pulley.


Thread: Just bought an ML7, what should i do first?
16/11/2019 08:59:11

If I remember correctly the handle acts as a locknut to the indicator dial, both of them being threaded. The best tactic might be to undo the two cap headed screws, grip the threaded section of the screw in the vice soft jaws and attack it that way.

You might be interested to know that ML8 wood lathes were often supplied with a metal lathe conversion, consisting of cross and topsides, which in my experience, have had very little use. I bought an ML8 and the seller gave me a brand new one, still coated in thick grease, as an after thought just as I was leaving. They occasionally appear on eBay from time to time.

Thread: Unusual GPO hammer?
30/09/2019 09:37:18


I think the point was that the units of issue were not always sensible and, if you were a rural linesman, out of reasonable reach of a store and at the end of a long day out in the rain, trying to guess what the unit of issue might be (bearing in mind the nearest rate book with its family bible proportions probably resided remotely in your bosses office) mistakes were likely. We were a comms company after all and I think a quick 'phone message from the store-man to check what was really wanted might have fixed it, I think most times they were just having a laugh.

By contrast a chair bound "engineer" with access to the book and a background of finding his way around it would seldom slip up I guess.

Worse, there was no apparent way back for over-ordered stores so I remember abundant amounts of wide insulation tape, washing up liquid, red coloured marker cards and many more items being offered around to all and sundry to try and lose them.

Don Cox

30/09/2019 08:41:28

My career progression with PO/BT reads exactly the same as Peter Shaw's, except my attendance span was 1963 to 96 when an indecently financial incentive tempted me to take the money and run at age 50. Indeed my level 2 manager during a significant part of my time there was a gentleman also named Peter Shaw.

I enjoyed repairing 'phones and call connect (switchboards etc) systems and also maintaining exchanges at various times. For ten years I looked after rural exchanges all on my own, the last selection included two TXE2s (processor controlled reed relay switched "electronic" exchanges) and a couple of UAX 13s (Unit automatic Strowger exchanges, I also had a UAX 14 at one time too), I look back on this period as the high point of my time there.

The rate book, or "Vocabulary of Engineering Stores" as it was also called, had one major failing in my experience. Items were listed with a "Unit of Issue" which did not always make sense. For instance, for wood screws it was 200, which resulted in one of my inexperienced colleagues receiving 30 boxes of 1" X 6 screws with an accompanying note from the store-man saying that this was all he had in his stock but that the remainder of the 200 boxes ordered would follow as soon as he got them, likewise jumper wire was "per metre" which resulted in a copy of the demand note arriving with a metre length of blue/yellow wire stapled to the top instead of the expected 200M drum. This situation was greatly exacerbated by the closure of local stores counters when the store-man could talk to you, and their replacement with centralised stores accessible only by Fax.

I enjoyed my time there (with the possible exception of my three years as a manager), the camaraderie was great, the training generally excellent, and it gave us, and still gives us, (my wife was also a GPO telephonist) a good living.

Don Cox

28/09/2019 21:12:45

God's Poor Orphans when i worked for them. I did pretty much all of the job types mentioned above, and quite a few more during the 33 years I was with them. Quite a few hammers were shortened to fit inside a tool wallet no. 3 which was the one carried by most linesmen (I was one of them too for a while).


Thread: Just bought an ML7, what should i do first?
14/09/2019 14:27:12


A couple of years back I was lucky enough to inherit a couple of Valvespout oilers. These have small, on/off controllable, nozzles which will fit into the original Myford "flush ball" type oilers ball apertures and those in he grease nipple types too. The balls are then pushed off of their seats to allow oil in, I have one with H32 and the other with k68 grade oil in, they both easily deliver controlled amounts into all of the oilers on my two Myford 7s and an ML8 . Have a look at one on:


08/09/2019 09:13:51

My 1949 ML7 came with a pair of Rotherams oilers, which are really just a pair of oil cups with rotating closable tops and which require topping up at each use. I later bought a pair of "cheap" oilers with sight glasses off of eBay, but could never seem to get them adjusted to deliver the right amount when in use and to stop oiling when they were off. Eventually I bit the bullet and bought a S/H pair of Adams oilers, as fitted by Myford on ML7s later than mine, and over a few days of occasional tweaking I can now say that oil is delivered when needed and stops completely in the off position. Adams are still out there, but at a price I guess: Good luck with your lathe, I still have mine, I couldn't let it go after the amount of TLC I lavished on it and it now resides in my workshop in a state of semi-retirement, alongside a 1963 S7 which now does most of the work.


Thread: strange power socket
15/08/2019 09:08:48

My father ran his own electrical contracting business following the second world war and was able to have the opportunity to buy a house on a small development, on the outskirts of Bath, where he was installing the electrics. As I understood it in later years (I was three when we moved in) ring mains were a new innovation then, everything previously had been spur wired and sockets were usually a maximum of 15A. As domestic electrical appliances became more common more sockets were needed (I have seen electric irons run off of lamp holders) which created cupboards full of switch fuses to control each socket, some of these were double pole fused which made for even more ironwork. He opted to use the Wylex plug and socket system and I remember our house being unusually well provide with socket outlets, all neatly terminated to a single consumer unit. Meanwhile the MK system was starting to appear and I think the British Standard was written around this. In the end he was forced to accept the change and MK pattern became the order of the day in his house. Some while back a 16A plug design was talked about but never adopted.

Thread: Meter Probe
13/08/2019 09:42:35

Over the 33 years I worked for PO/BT I had pretty much daily contact with their multi-meters, both as an exchange maintainer and as a linesman. Over that time the test gear was updated and the test leads too. One of the more annoying "improvements" was to the test leads which joined the probes, pictured above in the original posting, to the meter. Later ones of these had spring loaded insulating shrouds which covered the bare metal lead ends if they weren't plugged in. These had the very annoying effect of forcing the probes off of the end of the meter leads at the crucial moment. The need to get the probe onto a soldered tag deep inside a switch was difficult enough without the thing coming away in your hand just as you were going to look at the meter.

The latest standard test leads are next to useless in those type of circumstances, so the message must be look after any of this kit you still have, there ain't going to be anymore.


12/08/2019 19:21:14

I'm pretty sure those were the ones which came with most B.T. test gear when I last worked for them, now 23 years ago. In all that time I've never been able to track down a source of supply for replacements and I too have had to buy sub standard flimsy stuff. I'll be interested to see what else comes up.


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