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Member postings for Bill Pudney

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

Thread: Did i make the right choice buying an old banger Myford lathe.
20/02/2020 02:07:45

In WW2 my dear old Dad was an engine fitter in the RAF, for the last 3 or 4 years on Lancaster squadrons and Merlins. He told a couple of stories...

1/ The way of identifying an RR engine from a Packard one without removing cowlings etc was to stick a hand up an exhaust port, an RR engine was cleaned up and smooth a Packard one was "as cast", not to say it was rough, just not as smooth as a RR one.

2/ On the squadrons RR engines and Packard engines were considered interchangeable. When an aircraft was built, in the build documentation the engine number and manufacturer would be indicated. Due to the demands of active service it wasn't unusual for non original engines to be installed as time went along, these could be either RR or Packard.

3/ Apparently each engine had it's own toolkit. If an aircraft was lost or an engine destroyed, the toolkit would be returned to stores and subsequently reassigned to another engine. This didn't stop various bits of a toolkit going missing. As late as the mid 70s I can remember Dad saying, "....careful with that one son, that's a Merlin spanner".

4/ Each engine obviously had its own throttle in the cockpit, part of the arrangement was an emergency boost set up, which required the throttle to be pushed though a "tell tale" wire and enabled a short (I think 5 minutes) burst of absolute maximum power. One of Dads aircraft flew back from Berlin with two dead engines, one at about quarter power and the fourth with the throttle through the wire, flying at ever decreasing altitude the aircraft crossed the coast over East Anglia, only requiring the undercarriage to be lowered to land. At the end of the runway everything was switched off and the fourth engine just went clank clank and stopped, after several hours at emergency power. RR took the motor back and tried to find out why it had lasted so long.

Dad loved Merlins!! He wasn't particularly sentimental but he did go a bit misty eyed when talking about them.....except for the times that he had to do an engine change with snow on the ground and the aircraft at dispersal!!

cheers

Bill

Edited By Bill Pudney on 20/02/2020 02:09:52

Thread: Fast bit of engineering work.
14/02/2020 01:23:36

John Paton... Do I remember Bob Wells?? I'm in Australia now, so whilst I know the name, I never met Bob. However my (sadly late) elder brother, Chris, also flew free flight (F1A) largely at Middle Wallop, so I'm fairly sure that he would have at least known Bob. Bob was famous for his beautifully built models which flew so well. As it happens I too flew Wakefields, I think that Bobs models were predominately balsa and spruce, rather than composite.

George.....Physio. Spot on, the physio is absolutely vital. Where I had my knee "done" they had a machine which bent and extended the knee, with adjustable rate and amplitude. The nurses would strap you onto this machine before coming round from the anaesthetic. I also had to do hydrotherapy two or three times a week. Well worth all the pain though!!

cheers

Bill

13/02/2020 04:21:43

I had a knee replacement in 2001...the twin towers disaster happened whilst I was in hospital. At the time I used to fly free flight model aeroplanes for an obsession, which entailed A LOT of walking. Prior to the knee replacement I had difficulties completing competitions; frequent early retirements were common. After the op. no worries!! I was in hospital for 3 days, the exit criteria were, 1/ Being able to bend knee more than 90 degrees, and hyperextend to "straight", 2/ Being able to walk with the use of a stick, 3/ Being able to negotiate stairs. There followed about 6 weeks of physio, with bucket loads of painkillers. It was well worth all the physio and pain...which was considerable!!

cheers

Bill

Thread: Metric V Imperial Measurement
08/02/2020 01:38:27

For what it's worth, in the mid 70s I was fortunate enough to be working as a ships draughtsman on the T22 frigate which became HMS Broadsword. This ship was all metric, and I was told that it was the first ship classified as "metric" to be designed and built by the MOD(N)

Since then I have been happy using either imperial or metric, although my preference is for metric, so much more logical than basing a system of measurement on the length of a random thumb, or forearm or whatever!!

cheers

Bill

Thread: New Nimrods arriving
05/02/2020 10:45:12

I used to work for BAE Systems. When the Nimrod MRA4 was cancelled I heard that there was a huge sigh of relief around the company.

cheers

Bill

Thread: Driving Small Taps
16/01/2020 05:15:16

I do all my tapping powered by hand. Virtually all of the threads I tap are M6 or under. My "go to" tap holders are Starrett "T" holders, there are two, a small one which does everything under M4 and a large one which does everything over that. If the thread is over M6 (unusual for me) a conventional bar type tap holder is used. Some sort of centre is ALWAYS used to ensure that the tap stays lined up. If an array of holes is being tapped, the centres are marked out wherever possible using a height gauge, then into the (Sieg X2) mill, an optical centring scope lines everything up, spotting drill provides a starting point, pilot drill, tapping drill, countersink the hole to slightly over thread size; tap 1, using tapping fluid, clean swarf from hole; tap 2 using tapping fluid, clean swarf from hole; tap 3 using tapping fluid, clean swarf from hole. Then I move on to the next hole, starting with the centring scope...Sometimes only taps 2 and 3 are used. I must try spiral flute taps!!

I am about half way through tapping 16 x M3 x 0.5 in al. alloy, so far all the threads are good, to depth, they are blind, all point in about the same direction and (tempting fate here!) no broken taps. Yes, it does take a bit longer, but then I'm not on piecework!

cheers

Bill

Edited By Bill Pudney on 16/01/2020 05:16:58

Thread: Broken Taps
28/12/2019 02:43:44

When I had to work for a living we had to make a small sample part from 316 SS. The shape of the part suggested that plate should be used, fortunately some was found. The material work hardened so fast that it was virtually impossible to machine. Some enquiries were made of the supplier and I was told that plate was made to be weldable rather than machineable. Bar was made to be machineable, and not weldable, and to make it machineable a small measure of (I think) sulphur was added. So some bar was obtained and found to machine beautifully.

This was up here in Australia, so it may only apply here, although apparently Australia hasn't made stainless steel for decades, or so I have been told.

Happy New Year and cheers!!

Bill

Thread: Nalon Viper
14/12/2019 01:58:10

I've just had a look at my motors and the cylinder holding down screws are 1.25" long, not 1.75" as stated on my set of drawings. This may make the cap head screws easier to obtain!!.

Also, a couple of weekends ago I started the running in process on #1, it had been delayed by other stuff. It goes very well!! Starts easily, fairly smooth, turns a 9" x 4" Taipan at about 11,400 rpm which is pretty good. There are a few issues with the needle valve assembly, so there have been further delays whilst I try and put that right!!

I'm envious that you have a Velo to polish!! One of my favourite bikes!!

All the best

Bill

Thread: Long bed lathes affected by the tide
30/11/2019 00:40:18

Two things....

1/ Where I did my apprenticeship, at Saunders Roe (later became BHC) East Cowes IOW. The machine shop was about 25...30 feet away from the sea wall. The company designed and built a large mill to machine the wing spars for the Princess flying boat, the mill had a bed 60 odd feet long, but only about two feet wide. This machine was installed in the corner of the building nearest the sea wall. When I was in the Millwrights dept I had to do some work on some equipment adjacent to this mill. My curiosity was aroused by the tide tables on the wall near the machine. I asked my boss, George the full time machine shop maintenance man about the tide tables and he explained....due to the proximity of the sea the machine bed moved up and down dependant on the tide state, there was only one guy who knew how to make accurate parts. He depended on the tide tables, and as the cutter traversed the bed, the cutter height had to be adjusted to suit the tide state. He did this with chalk marks on the bed with arrows to indicate "up" or "down" and a number to indicate dimension change. The expert had retired before my time, but was called back when there was a need. The last job was Vickers Valiant wing spars, apparently there was a giant corporate sigh of relief when the Valiant was scrapped!!

2/ I also worked at Vosper Thornycroft at their Southampton yard. The yard was established in the 1870s, the centenary of the yard was celebrated whilst I was there. In the machine shop the was a huge lathe designed purely to machine propeller shafts for destroyers. The whole yard knew when this machine was being used as there was a very low frequency rumble which could be heard and felt all over the yard

The Saunders Roe/BHC and Vosper Thornycroft sites where I worked are now pretty much closed. They both seem to be car parks......

cheers

Bill

Thread: Exotic welding
29/11/2019 09:30:40

On a slightly different scale, one of the top welders where I used to work, cut a coke can open and made a flat sheet, then cut that in half, so he ended up with two pieces of al. alloy sheet about 150mm x 60mm x 0.2mm thick. He then welded to two sheets back together to form one piece about 150mm x 120mm x 0.2mm thick.

Well I was impressed!!

cheers

Bill

Thread: Lathe chuck guards - how many folk use them?
31/10/2019 05:52:15

My most used lathe is a Sieg C3. The chuck guard was removed the first time I used the faceplate, but the switch and associated wiring stayed in place until I had the lathe apart, when the switch and wiring were removed and replaced by a wire link on the PCB. I sometimes use a bit of sheet polycarbonate, if the chips are hot and/or dirty.

cheers

Bill

Thread: Nalon Viper
29/10/2019 02:02:54

I was able to get 6BA socket head screws from GWR Fasteners, at least for the bearing housing and backplates. They no longer list the longer (1.25"??) cylinder retaining screws, afraid I cannot remember where I got mine. I've just had a look at the engines and mine are definitely 6BA SHCS.

cheers

Bill

Thread: Tools of unknown types.
29/10/2019 01:53:12

The toolholders and toolpost are Siegs design, they do different sizes for different size lathes. They work moderately well but are not as good as some of the better quality QCTPs.

cheers

Bill

Thread: Nalon Viper
19/10/2019 01:57:49

Both of mine used a machined from the solid crankpin. They were finished as well as I could do. Finished up with a "poor mans ground finish"....emery sticks and oil!! To use a pressed in needle roller would be somewhat better from a performance point of view, but there are technical issues, the crankweb needs to be a lot thicker, I've heard a minimum of 1.2 times the pin diameter, to ensure that the pin is well supported. However, some of my commercial modern highish performance 2.5cc motors use a 4.0mm diameter crankpin, which would "only" require a 4.8 or 5.0mm thick web. Theoretically. Then you have to answer the question "....Is this a Nalon Viper??" !!

Chrome plating various bits would be very nice, but introduces yet another layer of complexity as any plating would need grinding or at least honing/lapping.

You are spot on about the mess that cast iron makes, I recently finished a carriage and compound slide for a small (70mm centre height) lathe. This required a lot of machining, although I cleaned up after every session, (sometimes after every cut!), and took care with chip shields etc, the cast iron dust got everywhere.

best of luck!

cheers

Bill

18/10/2019 07:28:17

I made a couple of Nalon Vipers a year or so ago, there is a photo of my Mk1 in an album. I used 6061 T651 for the front bearing housing, fins and rear backplate, 2014 T3 for the crankcase, 4140 steel for the crankshaft, meehanite for the pistons, 12S14 (similar to leaded EN1a) for the liner, 2024 T3 for the conrod, delrin for the rotary disc. Please forgive the furrin material specs, but I'm in Australia and most of our metal comes in American specs.

Incidentally 2024 T4 or better is usually recommended for conrods, and it is certainly very good, but it's also expensive, I once was quoted US$40 for a 24" length of 1/2" diameter bar which I found (just) acceptable, but it was US$120 postage from America!! The reason that 2024 is often stated as the preferred material was because of its better properties at elevated temperatures. So I investigated and proved to my satisfaction that 7075 T651 was ALMOST as good, except for a tiny drop at fairly high temperatures, around 200 degrees C if I remember. The big advantage was that my local supplier could supply 1/2" bar at about AUS$20 a meter!!

best of luck!!

cheers

Bill

Thread: Cheap ER collet advice please
14/10/2019 02:45:17
Posted by Bandersnatch on 14/10/2019 00:45:39:
Posted by Mike Crossfield on 13/10/2019 23:03:41:

I’ve bought ER25 collets a couple of times from CTC and been very happy with the quality and price.

+1

I've bought both ER11 and ER32 collets and chucks from CTC, as well as other stuff...boring head, cutters etc. All good gear. Once again I have no doubt that there is better quality stuff available, but all of CTC kit has been fit for purpose. My only problem with CTC is that delivery can take a while, not as quick as Arc Euro for instance.

cheers

Bill

Thread: Metrication of models
05/10/2019 02:52:17

I was a contract drafty at a machinery company in the early 70s. They used fractional dimensions on casting drawings, decimal dimensions on fabricated and machining drawings. It made some sort of sense at the time!!

I started work for the MoD (N) in the mid 70s and had the privilege of working on what I was told was the first "metric" ship built for the Real Navy, (the Type 22 class of frigates).

cheers

Bill

Thread: Clock #1
03/10/2019 05:33:32

Congratulations!! It's my ambition to build a clock, so I am VERY envious of your achievement!!

cheers

Bill

Thread: Aero Fuel
29/09/2019 04:31:57

My dear old Dad was an engine fitter on (mainly) Lancasters during the War. He said that there were basically two types of petrol, "Pool" petrol which was about 75 or 80 octane and for general transport use...cars, trucks, motor cycles etc; and Aviation fuel which was something like 105 or 110 octane and STRICTLY for use only in aircraft. One type had a dye in it so that illegal/improper use was immediately obvious.

cheers

Bill

Thread: M8x1 left hand tap.
18/09/2019 03:12:55

Drill Service at Horley would be another suggestion. I got a couple of M10 x 1.0 LH taps and a die from them, some time ago.

cheers

Bill

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