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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: Workshop and Drilling holes with an ER collet chuck
02/05/2021 03:08:41

I'm sure others more pedantic than I am will say that using an ER chuck rather than a drill chuck is likely to bring on the end of the World. However I do exactly the same. As I spot drill, drill, tapping drill and tap in the mill, chopping to a drill chuck after any previous milling ops. would be a right Royal PITA. I use ER32, with a full metric set and some imperial collets and quite a few "doubles". If the plan is to drill and tap several holes the various tools get slid into the appropriate collet and placed carefully on the bench. It then becomes a simple task to simply remove the "old" cutter, with collet and replace with the next cutter and it's collet.

Go ahead!! Damn the torpedoes!!



ps  For what it's worth I spot drill, drill, tap drill, countersink and tap all in the mill.  The X and Y slides are locked tight.  I cannot remember the last time I broke a tap!!


Edited By Bill Pudney on 02/05/2021 03:13:14

Thread: B&D workmate
26/04/2021 01:11:12

Dad gave me a B&D version in the early 70s, I've still got it. It doesn't get used a lot, but when it is used it's invaluable. Wonderful piece of kit!!



Thread: JD Metals
25/04/2021 03:12:12

After reading this thread, I have just had a quick look at their website. My main interests involve alum alloy, so I went straight to the "Aluminium" page and looked for details of alloy type and temper. Nothing. So if I was living in the UK, which I'm not, as far as I'm concerned they would be off of my "suppliers" list.



Thread: Distorted ship's hull steel panels
15/04/2021 00:57:06

Thank you all for joining the chat. But I still cannot see why, when they build a big Naval ship, the plates (panels?) all appear indented at launch.

>>>> Trust me Norm, it's the welding of the frames and bulkheads and longitudinals to the shell.

Bill kindly explains the welding might pull in the centres, but that seems odd - couldn't they design the ribs to match the planned curvature in all places?

>>>>The primary consideration is what the sea "sees", that is the actual part of the shell that gets wet. Predicting what the shell is going to do post welding, is certainly possible, however, the shell plating is distorting between the frames/bulkheads and longitudinals.

A big ship like a liner with heavy plates has them all rolled to match the curvature; I don't think the same plate distortion is seen. So, are we thinking that the Naval ships are made with much thinner plates, to make a lighter and faster ship, and try as they might they cannot make them neatly curved all over, and have to resort to seven tonnes of epoxy filler?

>>>Some plates are flat others are rolled to shape, it depends on where they are destined for. Once again, the seven tonnes of epoxy is there for hydrodynamic reasons only. The epoxy is applied only below the waterline. Whether or not the below waterline aesthetics are improved or not is irrelevant and as such not a consideration

So why can't thin steel panels be rolled to a correct curve, and welded to the curved bulkheads and ribs, so that it all looks neat? There is something we are not understanding, and that was the whole point of my first question

.>>>The shell plating is rolled to the correct shape, the plating is distorted by the welding. No doubt it would be feasible to go over the entire above waterline area of the shell and carefully heat and dress the distorted panels flat, so the ships side presented a pleasing appearance to the tax paying population. This however might render the ship rather expensive.

My guess is that localised heating and cooling of the skin from the sun leads to expansion that either has to pop in or out, and standard practice says to make them all pop in. I wonder if this is why the same panel distortion is seen in welded locomotive tenders?

>>> The distortion is not caused by the sun.

But, if the panels are flexing in and out with sun heating, how does the seven tonnes of epoxy stay in shape?

>>> The epoxy is only below the waterline. The sun does not cause the shell plating to "pop" in and out.

italically yours


14/04/2021 22:56:19

The MoD when publishing data about HM ships, they can be a little coy about some information. For instance regarding top speed all they say is " excess of 30 knots" In Broadswords case it was well in excess of 30 knots.



14/04/2021 09:45:20

Some hours later I have just realised that I had "hydrodynamic", "homogenises" and "aesthetics" all in the same sentence. Obviously I was sleepwalking and snacking on a thesaurus.



14/04/2021 00:43:36

The epoxy compound is only used below the waterline. It is purely functional, it reduces hydrodynamic drag and it reduces and homogenises hull generated noise, aesthetics are not a factor.

Attempting to predict the ultimate shape of the hull and rolling the shell plating so that welding induced distortion is eliminated would probably be theoretically possible but almost certainly outside any cost budget.

It wasn't only the non slip floor coatings that burned and gave off toxic fumes, it was mattresses, bedding, even the sailors clothing was polyester so it burned and melted onto the skin. Horrible.

Performance of a modern warship can be fairly spectacular. Again I was told by someone who would know that HMS Broadsword would accelerate from 0 to 30mph faster than a sports car. I always assumed this was an MG Midget type sports car, not a 7 litre AC Cobra type of sports car!! Certainly being on a launch alongside when she did a standing start sprint, was very impressive.



13/04/2021 02:49:57

Modern destroyers should not be confused with destroyers of a bye gone age. For instance a modern T45 destroyer displaces over 7,000 tonnes and are about 500' stem to stern. An early "V" class destroyer laid down in 1916 was about 1190 tons and 300 feet long. To provide an effective escort for the modern fast battleships in WW2 the "L" and "M" class were built. They displaced around 2,000 tons and were 360 feet stem to stern.

Even HMS Queen Elizabeth had visible between frame and longitudinal panel warping at the time of her launch



11/04/2021 01:51:45

Pauls addition is interesting and provides an alternative perspective.

One of the reasons that weight is important is the increase in electronics and cabling in modern ships. An attempt to reduce "top weight" by the use of light alloy superstructure proved to be a dead end. The T21 class frigates had light alloy everything above the weatherdeck, and it was realised fairly early on when the first of class (Amazon) had a fire when fitting out, the al. alloy structure just burn't away. Sadly this came home to roost in the Falklands. The superstructure of later ships, is of fairly light gauge steel. Interestingly (well I thought so!!) the paint scheme is very important to prevent rust. It's not just a case of slapping on another coat of battleship grey!

I was only involved with two classes of ship, T21 and T22. They both used constant frame and longitudinal spacing (36" x 24" for T21 and 600mm x 1000mm for T22). The variations required to comply with longitudinal strength were achieved by varying the shell thickness as required.



10/04/2021 23:38:36

Its caused by the welding on the 'inside" of the shell. There are frames and/or bulkheads at approximately 1 metre intervals along the length of the hull, and longitudinals at approximately every 600mm going from the sharp end to the blunt end. These cause "panels" all over the external surface of the ship. When the welding happens the "panels"are pulled in by the action of the welding, causing the distortion mentioned. The distortion varies but can be up to about 10mm. The welding of the frames and longitudinals to the ships shell (the outer plating visble from the outside of the ship, is continuous. Shell plating thickness varies considerably from a maximum at the deck edge and the "turn of the bilge" amidships to a minimum towards the bow and stern. I was told by someone who would know that about seven tonnes of epoxy filler is used to smooth out the hull on your average frigate, this improves performance and reduces the hull generated noise.

Ady1 is right about the weight, considerable care is taken to ensure that weight is minimised. Not to sure about the "...big speedboats with guns", though!!

Hope this helps



Thread: Recommended suppliers and services
08/04/2021 11:06:08

For an Australian perspective, Ausee Tools are good, as are LPG Toolmakers, Eccentric Engineering & E.J. Winter. RS Australia are surprising, free shipping!! CTC Tooling in Hong Kong have been excellent, their delivery times have improved recently as well.

In Adelaide most of my metal comes from either Surman Metals for cast iron and gunmetal or Bohler Uddeholm for specific grades of steel

My "go to" UK shops are Arc Euro, I don't know what they've done to their freight people but 4 days from UK to Australia is pretty spectacular!! Drill Service do top class stuff. Tracy Tools are excellent. I was disappointed to find that Cutwel Tools do not supply to Australia.

Finally the USA .....Little Machine Shop is good, MariTool are top quality suppliers of top quality cutters



Thread: Gluing Aluminium
31/03/2021 07:38:36

To prevent corrosion and enable better adhesive efficiency, consider anodising all the aluminium parts before gluing. It makes a world of difference.



30/03/2021 22:59:44

Agree with most of the above. In addition if you are using an epoxy based adhesive ,it would be good to clamp the joint whilst the adhesive is curing, and leave in a warm dry place for the recommended cure time. In general long cure adhesives have better properties than slow cure.



Thread: RH vs LH threads
30/03/2021 09:42:43

Sorry I mean't to say the single cylinder one, not the V8!! The V8 was certainly an amazing design, but for me the single is so beautiful!!

cheers again


30/03/2021 00:14:13

I read The Book in the mid 70s, it seemed appropriate at the time. I am a technical person and have been all my life, I also understand the need for beautiful things, and beautiful design. F'instance, for me a 1957 Grand Prix Moto Guzzi 500cc is just about the epitome of pragmatic, elegant design. Of course there are examples wherever you look, but for me that 'Guzzi is perfect!!



Thread: Rubbish Milling Finish in Aluminium
29/03/2021 04:02:39

Cannot recommend the use of sharp cutters and some sort of fluid enough. My preference is for paraffin/kero on al alloy. WD40 is ok but leaves a waxy finish in the overspray areas. Fantastic for displacing water though!! Kero is probably cheaper as well.



Thread: Low head Cap Screws
29/03/2021 01:50:23

Big end bolts and nuts. Mike Pooles comments about replacing them is right on the money. They are generally the most highly specified part in a motor. Material, heat treatment, surface finish, tolerance regime, post manufacture handling and storage etc etc

Socket head screws, "name" manufacturers like Unbrako, Holo Chrome etc are manufactured to very high specs and their fasteners are of uniformly high and reliable standards. Personally I wouldn't trust non branded fasteners as far as I could spit.



27/03/2021 00:34:54

Google "Unbrako" and you can download the Unbrako Catalogue/Engineering Guide with more information than you will ever need to know about socket head fasteners.



Thread: CNC - Easy as pressing a button - Not
21/03/2021 23:41:41

Not a CNC failure, butttt.....Many, many years ago, there was a large grinder, it had a vertical axis cylindrical wheel about 24" diameter, the bed of the machine was about 20 feet long. The machine had a rapid traverse that was pretty quick. I was in an adjacent workshop, and wasn't involved, other than as a witness, fortunately. The experienced operator was setting the machine up and as a result had the guards off or down, the workpiece (apparently) wasn't clamped down, it was a piece of steel about 20" diameter and 2 or three inches thick. Anyway, the operator was just checking the coolant flow, with the bed at an extreme of travel, i.e. right uo one end, when the bed traversed at high speed, flinging the workpiece the full length of the workshop, about 50 or 60 feet, it started at about 5' off the ground, and finished about 2'. It flew down the walkway, between workbenches and missed the nine or ten people working at those benches, and impaled itself in the brick wall. Several people lost their lunch. Rapidly made me realise how dangerous working for a living could be!!



Thread: JB Weld
17/03/2021 20:50:06

Hi Tug, Thanks for the kind comments!! The motor with the composite piston is a PAW 15 TBR CT....that's 2.5cc, Twin Ball Race, Combat Tuned. It's one of two motors that I bought in about 2005 when I intended to use them in Vintage Combat. It turned out that I was too old and slow for Vintage Combat, but finding that out took several attempts and the motor in question was buried in the sand that is our flying field. As a result of which the piston was damaged, requiring replacement.

I still haven't built a model for the Sugden, but it's likely to be a Mercury New Junior Monitor.



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