Sommaire pour September 2022 de Model Engineer & Workshop

Phew What a Scorcher! Last month saw the hottest ever recorded in the UK, with multiple locations having temperatures reaching over 40°C. I hope that readers were able to keep themselves reasonably cool and comfortable and did not suffer distress from such heat. Naturally all record-breaking temperatures must be recorded with proper meteorological equipment to be valid, it is easy for temperatures to go far higher, especially in full sunlight. Here in Wales we didn’t get the full impact of the hottest day with temperatures rising to around a ‘mere’ 37°C, but when I checked the max-min thermometer on the outside of my workshop it indicated 47.5°C. This is in a position exposed to the sun until about an hour before the sun reaches its highest, so the temperature in…

Readers! We want to hear from you! Drop us a line sharing your advice, questions or opinions. Why not send us a picture of your latest workshop creation, or that strange tool you found in a boot sale? Email your contributions to meweditor@mortons.co.uk. Samuel Cody’s Tree Dear Neil, thanks very much to Keith Beaumont of Bracknell, whose letter about William Cody (actually Sam) and the tree at Farnborough you published in issue 312 in February. I was an air traffic controller at Farnborough in the late 70’s/ early 80’s and although the project was ‘secret’ (as Keith explains) we were aware something had been done to preserve the tree. Those most ‘in the know’ informed us sagely that it had been simply encased in glass fibre; so it’s really interesting…

Some time ago I bought a 40mm diameter shell mill and mounted it on a home-made arbor with a ⅝” diameter parallel shank that fitted into a collet on my Thiel mill, photo 1. Thiel collets are similar in shape to R8 collets. Regrettably, the Thiel has now gone to a new home, but I kept the shell mill and some other tooling that I could use. My new milling machine has only a 2MT taper in the spindle. Although slender by some standards, it means I can share taper tooling with my lathe that also has a 2MT spindle. Mounting the shell mill into an ER32 collet meant the overhang was unacceptable and trying to use it, it waved around like a flag in the breeze. It was relegated…

I borrowed a boring bar to re-bore the engine of one of our David Brown tractors. This was my first mistake – breaking my own rule of never borrowing or lending tools or equipment. Although rather elderly and not of the best design, with some fettling I managed to get the borrowed machine cutting with repeatable accuracy and reasonable surface finish. I was so confident that all was well that I set the machine to work on a cut and went off to make a cup of tea. When I got back with my tea, I found that the machine had stalled in the cut and the smoke of doom was pouring out of the drive motor’s ventilation openings. “That’s good,” I thought. “I have always wondered how difficult it…

Driving Truck David Allen adds the superstructure to complete his 5-inch gauge driving truck. IMLEC Dave Tompkins reports on the last day of the International Model Locomotive Efficiency Competition at Guildford. Oscillator Having completed his three-cylinder oscillating engine, Hotspur starts work on a suitable boiler. Dreaming Spires John Arrowsmith spends a weekend in Oxford, at the club’s rally in Cutteslowe Park. Roger’s Rambling Roger Curtis continues to fight a rearguard action against metrication, arguing that the Imperial system is far more in tune with Mother Nature. ON SALE 26 AUGUST 2022…

We were recently invited by the Airbrush Company to review HR Hobbies Airbrush-ready metallic paints, following their launch in the UK with new branding. The range of paints includes a wide range of metallic lacquers, primers and varnishes for producing realistic and durable metal finishes on aircraft, car and truck models and armour. The HR Hobbies lacquers are pre-thinned for airbrush use, and drying time is under 10 minutes. The range includes airframe aluminium, silver, gold, copper and many more finishes as well as specialist primers and airbrush cleaner, photo 1. The obvious test for metallic lacquers is to see how well they emulate the appearance of metal in a real-world situation. While I didn’t have any models or similar suitable for a test, I do know a crafter, Dianne…

Next year is the 125th anniversary of Model Engineer magazine. We’ve been looking at how MEW can celebrate its fellow publication’s milestone; to whet your appetite here’s a classic ‘tip’ from 1923. When tapping shallow holes, it is difficult to start the tap at right angles to a machined surface, more so when a taper tap cannot be employed due to the holes shallowness. The [adjacent] drawing shows a simple form of a tap guidance in section; it is turned from brass or mild steel round bar-, and its length overall being somewhat shorter than the tap, in accordance with the depth of the hole to be tapped.…

Typically, I allow my files to lay on the bench when in use and, worse, keep them all stored together in a drawer when not. Having invested in some quality new 150mm files, I decided it was time I had a better way of storing them so there was less chance of them knocking together, which reduces their life, and make access quicker and easier, photo 1. Having a few pieces of white plastic waste pipe left over from a recent kitchen refurbishment my first thought was to cut lengths and bundle them together but, at around 40mm diameter, they are too large to be practical for smaller single files. In effect, three files will sit in a tube with relative ease, so I made some 3D printed dividers. Three…

To make the hexagon hole without a press it would be possible to press the cutter into the hole with a bench vice as long as it is possible to keep the cutter square to the holder. I would not recommend using a hammer as the hexagon key is brittle and may shatter. Bearing block for tool holder To hold the riveting tool holder on the base, it required a bearing block so a piece of 48mm diameter steel was cut on the bandsaw to approximately 30mm long. This was then mounted in the lathe chuck and the face was cleaned up, the corner was deburred and then the part was turned around and remounted in the chuck. It was then reduced to 28mm long, centre drilled and opened up…

I recently took a trip to London, however due to circumstances I found myself with much of the day free as I waited for my off-peak return train. Much as I enjoyed visiting the music shops in Denmark Street (known as the UK’s ‘Tin Pan Alley’) and a visit to the Victoria and Albert Museum, I think readers will be most interested in some of the exhibits I saw at the Science Museum in Kensington. I would argue that this is more a museum of technology and engineering than one of basic science, but as such it is outstanding and well worth a visit. One of the first exhibits you see on entering the museum is the huge ‘house-built’ Pentrich Engine, photo 1. This is an important exhibit because in…

It all started when the workshop roof started to leak - again! when I moved to my present house, I built a workshop in one half of the double garage, insulating the roof with glass fibre insulation. The garage roof was covered with ‘Big Six’ galvanised steel box-profile roofing sheets. This type of roof is held down using screws fitted with soft sealing washers under the heads which last for around 30 years or so. As the garage roof was around this age, it had started leaking in a few places. I rectified this using a petrolatum cloth tape - such as Denso tape or Sylglas tape. This was a reasonable cure at the time but, after 10 years exposure to the weather, the roof started leaking again as the…

BEFORE THE AGE of mass or well-organised production, hand fitting with scrapers was an accepted part of manufacture. Today it is still employed for guideways of machine tools and finishing surface, plates, on which the attractive mottled effect is produced with scrapers. In addition, there are numerous occasions when it is necessary to remove buns or ease high spots for components to fit correctly, so it is probably as true as ever that no workshop or fitter’s kit is complete without a selection of hand scrapers. There are three common types of scrapers as illustrated in A. That called a bearing scraper has a curved blade with two cutting edges running to a rounded end or a point. It is relieved on the bottom, as shown in the section. The…

A Caliper Substitute TIP OF THE MONTH WINNER! This month’s winner is Stuart Macpherson of Wakefield, with a tip for making awkward measurements without a caliper. I had to make a template for a wall light and was indoors, so no vernier or set square but for quite a while I have had 2 six inch steel rules on my desk. They are fastened with a magnet just to keep them tidy. The photos show the magnet and their use to locate the slot on the lamp and transcribe it to the cardboard template. We have £30 in gift vouchers courtesy of engineering suppliers Chester Machine Tools for each month’s ‘Top Tip’. Email your workshop tips to meweditor@mortons.co.uk marking them ‘Readers Tips’, and you could be a winner. Try to…

The Allegro device is of course only able to provide one input to the Micro:Bit, but as these devices are sensitive to the direction of the magnetic field, it would be possible to stick two of them back-to-back to provide two outputs, each responding to a different magnetic pole, just like the Rohm device, if you wish to stick to the fig. 2 layout. Alternatively, you can use three of them in the fig. 1 arrangement, and it turns out that you can wire two of these devices in parallel and they will provide the necessary signal to the Micro:bit if either one of them is activated by a magnet, so the programme described above works with this arrangement without the need to use an additional input pin on the…

There is a downside to my suggested modifications of the two-movement approach. This might account for why I have not found any previous reference to it. In the initial approximation, the indexing angle was 360/N which is traditionally achieved by means of a dividing head on a milling machine. Movement 1 (the roll angle) is 360/4N. With appropriate division plates both these requirements can be met providing the number of holes used for the indexing angle will divide by 4. For example, a 24 tooth spur gear to be made on a dividing head with a 40:1 ratio would require 40/24 or 5/3 revolutions of the handle. So any indexing circle divisible by 3 would do the job. For a bevel gear this would need to be any circle divisible…