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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: Accuracy of Hand Drilled holes
08/10/2021 09:52:00

During my apprenticeship we had to make loft plates, typically 1/8" al.alloy, with an accurate photographic "picture" of what was required, printed on the sheet. They were usually developments of folded/pressed structural members, some were small 6" x 6", some were long and with a complex shape, the biggest I saw was about 72" x 12". The outline had lines from memory 0.006" or 0.010" wide, holes were indicated by crossed lines, with a circle appropriately sized for the drill bush destined for that hole, usually either 3/32" or 1/8" bore, with an outside diameter of something like 5/16" or 3/8". The bushes were very accurate, I think that they were sintered. The outline had to be filed to (ideally) half the line thickness, and the drill bush ideally would show half the line thickness all the way round. This is a long winded way of saying that, in my yoof I regularly achieved +/-0.003" or +/-0.005".

cheers

Bill

Thread: Motorcycle General Discussion
08/10/2021 06:10:19

Which all goes to show, how little we know!!

cheers

Bill

07/10/2021 23:33:01

I always thought that it was gyroscopic precession that provided this, so-called "counter steering" effect,. Back in the 70s I was interested in all this sort of thing, I did some experiments. The numbers that I remember are a bit vague, it was 50 years ago after all, but the principle remains. Riding along from walking pace up to about 15 mph, push forward on the right hand handlebar, bike turns left, with little or no lean. Over about 15mph the opposite is true, push forward on the right hand handlebar, the rotating front wheel resists the force with an opposite force which causes the motorcycle to lean and turn to the right. As the bike is ridden faster the resisting force increases considerably.

I would hazard a guess that the rotating mass of the front wheel would have some effect, so some of the huge front brake drums would probably make things worse. Another reason for using discs!!

cheers

Bill

Thread: Hardinge HLV H
30/09/2021 07:37:59

Probably 20 years ago work sold the last of two HLV H, well tooled, well maintained and well looked after. I believe it went for A$5,000. At that time the two guys who ran the turning section and who were not happy with "their" Hardinge being given away (their words), asked me to find out how much a new one cost. I had a look on the Hardinge website, and the basically equipped lathe was available "on special" for something like US$38,000. I had a chat with their local rep and he confirmed that they were not making any more, the normal list price was something over US$50,000. They are probably one of the best two manual lathes ever, up there with Schaublin.

cheers

Bill

Edited By Bill Pudney on 30/09/2021 07:38:43

Edited By Bill Pudney on 30/09/2021 07:39:50

Thread: Disposal of swarf
05/09/2021 23:29:59

There were many reasons for investigating the use of a compactor, 1/ We were filling up multiple skips per week with swarf. 2/ Said swarf being oily was dripping all over the area and causing concern because of groundwater contamination. Yes there is "groundwater" in South Australia, the driest State in the driest Continent!! 3/ Swarf had a fairly low recycling value, because it was dirty and low density.

The compactor ended up compacting the cleaned swarf to better than 90% of the density of the bar material, at least for the al.alloy swarf which was about 95% of the swarf generated. In fact the "pucks" generated by the compactor were machinable!! The scrappy liked it because instead of the 5 round trips of about 15km per week, they were able to make less than one trip per week, with many obvious benefits.

The recycler paid a premium for the compacted swarf, as it was clean and didn't require any operations (like cleaning) before dropping in the bucket to be melted.

I retired before it had paid for itself, but I believe that after 12 years it's still going strong.

cheers

Bill

05/09/2021 21:24:41
Posted by ega on 03/09/2021 14:39:09:

I understand that industry goes to some trouble to remove the cutting oil, etc from swarf.

How much difference does this contaminant make?

One of my last projects before retirement was the acquisition of a swarf compactor. The scrappy who was contracted to collect our swarf paid a significantly better price for clean compacted swarf compared to dirty "oily" uncompacted swarf, so we had a washing stage in the process. Interestingly (well, I thought so!) , the coolant which was drained from the swarf, was itself collected, filtered and cleaned, then reused. The Boss, who was a Yorkshireman was suitably impressed (as only a Yorkshireman can be impressed) that we could get a (modest) income stream from coolant collection and swarf compaction!

cheers

Bill

Thread: Motorcycle wheel spindles
29/08/2021 23:02:04

I asked the question of Norman White (Norton restorer of note) "What material are Norton Commando wheel spindles?", his response was "EN16"

cheers

Bill

 

Edited By Bill Pudney on 29/08/2021 23:02:17

Thread: A SIMPLE POINT !
27/08/2021 23:58:37

I too agree with Howard Lewis, that school must have been crowded!!

cheers

Bill

p.s. I once got into a moderately warm discussion with a technical author, about the difference between a screw and a bolt. She took the issue to the CEO who decreed that "Bolts get shot from cross bows, end of argument", I wandered back to my drawing board (yes it was that long ago), muttering something like "perpetuating a falsehood"

Thread: Hello from the west country
26/08/2021 00:16:35

Welcome Colin. Roughly whereabouts outside Bath!! The Boss and I used to live in the married quarters at (the then) RAF Colerne, then at Radstock. This is a terrific site and masses of knowledge!!

cheers

Bill

Thread: Clinging to the Past
20/08/2021 01:26:57

During my working life I saw the diminution and/or elimination of many traditional skills. In my World when I was a young man, draftsmen were a highly skilled and vital part of an engineering enterprise. To become a draftsman, one of the prerequisites was to be a time served apprentice in a relevant field, this didn't mean that because you had done an apprenticeshio as a pastry chef you could reasonably be qualified to become, for instance, a draftsman in a machine tool business. When I left school at the age of about 17, the company where I did my apprenticeship employed about 40 to 50 degree qualified Engineers, across all disciplines, mechanical, aerodynamics, stress, electronics etc etc. At that time there were about 250 to 300 draftsmen. The total number of employees were between 3,000 and 3,500. When I retired about 13 years ago, the company where I worked employed several hundred degree qualified Engineers, and less than a dozen draftsmen. Most of the young engineers were employed as CAD operators pretending (my description) to be draftsmen

I spent a large part of the last twenty or so years of my working life running informal Design For Manufacture courses, because most of the Engineers had absolutely no idea how to make anything. Most had no idea what the difference was between a lathe and a mill for instance, let alone what each could do. They were superb at data and model manipulation, and so on but basically had not got the "link" between what was on the screen and what was or was not being produced.

Then there are the traditional trades, for instance Fitters........these days because widgets can be made so accurately the need for "fitting" has almost disappeared. Now the task is simply "assemble", the only requirement being the ability to read simple instructions........

cheers

Bill

Thread: Converting fractions to decimals
18/08/2021 08:20:50

[ says the man who never does the job ]

devil

MichaelG.

Hmmm. Just as well that I'm not sensitive, have a look at my albums.............

cheers

Bill

17/08/2021 23:39:43

As a smart arse I have avoided all the angst by drawing everything that I make in metric, as I feel that inches, feet, fractions etc are best left in the realm of Ancient Oddities.

cheers

Bill

p.s.Basically though I agree with Tug.................

Thread: Milling machine identification - "Deutsche Waffen Und Munitionsfabriken"
31/07/2021 02:47:21

In the mid 60s as an apprentice I spent some time underneath a capstan lathe, (making and fitting a coolant catch tray or something similar), which had a similar sort of plate....not the same but similar. It turned out that it was one of several, six or seven I think which were "War Reparations". They were just about worn out, but still earning their keep at least twenty years after the end of the conflict. Wish that I could remember the manufacturer!!

cheers

Bill

Thread: More Q's about surface finish.
26/07/2021 01:30:46

I suppose this is vaguely related, apologies if it isn't. Where I used to work they took great pride in their optical manufacturing capabilities. The prize piece of equipment was a diamond turning machine. It was used to generate mirrors, concave, flat and convex from aluminium. The surface finish was optically superb (apparently "cock on" is a term used by optics dudes.........much used in regards to the DTM). Usually machined al. alloy is very prone to micro damage from fingerprints and similar, but the DTM generated surface was not.....so I was told.

cheers

Bill

Thread: Aluminium
19/07/2021 23:12:32

My preference would be for fibreglass, but I appreciate that not everyone would agree. If it was mandated that al alloy must be used, my choice would be 5251. Motorcycle seats need to be able to resist bending and twisting as their fixing arrangements are seldom ideal. In addition they must resist corrosion. As the national debt is unlikely to run to anodising the completed seat pan, I would suggest investing in a good marine paint scheme prior to upholstering. By all means use 1050 if the motorcycle is unlikely to be ridden, but I can't imagine a Triton locked up in a shed!!

cheers

Bill

Thread: Vehicle reversing sensors
18/07/2021 10:49:19
Posted by Martin Cargill on 18/07/2021 07:59:13:

Reversing light, you flash ba****d. I have the mark one eyeball fitted to my series Land-Rover. If that fails I revert to the mark one ear and park by sound, You just pull forward a bit after the crunch noise.

 

Martin

Yep that's me, reversing lights, latest British technology...don't cha know............

cheers

Flash

Edited By Bill Pudney on 18/07/2021 10:49:43

18/07/2021 02:30:10

There was a time when I was just glad to get the reversing light on my MGBGT working!!

cheers

Bill

Thread: Motorcycle General Discussion
16/07/2021 10:38:14

Neil, I had a road Greeves, with a 250cc single cylinder Villiers motor, and those famous forks!! Superb steering and handling!! My bike would have been about the same as your Dad's, but with lights!!

cheers

Bill

Thread: Taps and Dies
16/07/2021 05:30:53

+1 for everything John Reese said!! In addition I stow a good tapping drill with the tap and die.

cheers

Bill

Thread: Scale gearbox (or how I leaned to love aluminium)
15/07/2021 23:10:29

Really nice work!!

The machinability of Aluminium is almost completely dependent on the grade and the temper. For instance pure aluminium in its' annealed state machines horribly, whereas some of the higher grades machine beautifully in the harder tempers. Where I used to work we did a comparison of machinability, the results could be summarised more or less as.........

Anything bought in a hardware shop is unlikely to machine well

Any Al Alloy grade 6061, 2011, 2024, 7075 machines well at temper T6 and better

Any Al Alloy grade 6061, 2011, 2024, 7075 machines poorly at T0

The preferred material was 6061 T651, it was cheap and available

For higher strength applications 7075 T651 was appropriate

It should be noted that the temper of the material is extremely important.

"T0" indicates that the material is annealed

"T6" indicates that the material has been tempered, the trailing "--51" indicates that the material has been stress relieved, stress relieving is a good thing.

In all cases a coolant should be used, WD40 is o.k., but kerosene (paraffin) is better. Really sharp cutters are recommended.

I understand that these material and temper specs may not mean much in the UK. They are internationally recognised though, so maybe a google search for Al Alloy equivalents may help

hope this helps

cheers

Bill

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