Sommaire pour March 2023 de Model Engineer & Workshop

The Law of Diminishing Returns In economics there is a principle that, grossly simplified, the more you invest in something the less you make per unit of investment – the law of diminishing returns. Let's backtrack a bit. I rather like using old-school tools and equipment in my workshop, but also in the day to day of life. I'd rather read a real book than an online one, for example. I also prefer vinyl to CDs and CDs to MP3s, simply on the grounds that it is nice to have a physical object that encapsulates the music. Now, despite having a beard, I engage in a bit of topiary to keep things tidy and that means a blade razor to deal with my wire-wool like fuzz. For several years I…

Wiring the modules referred to last time is simple, fig. 1, just connect the positive and negative leads from the cell to the BAT+ and BAT- connections on the board. You can supply power via the USB socket (which does not have any signal function) or supply up to 8V across the IN+ and IN- connections. It's important to bear in mind that these modules are not suitable for use with a 12v supply! One issues with using Li-ion batteries with many projects is that because they only produce rather less than 4V they are unsuitable for many applications that require a full 5V to work properly. The simple solution to this is a voltage booster module, such as that in photo 14. This example is based around an MT3608…

Please see fig. 1 for a definition of terms in die geometry. The most interesting features for sharpening are: the taper β (or chamfer) usually 20° to 30°, this is steeper than the one found on taps, the clearance angle α, the number of flutes, and the land width. There are three different types of button die: Die sharpening Here I'll use my attachment (see my article on sharpening taps in MEW 324) to grind the taper of the die which is the working part, photos 4 and 5. The same principle is used, the main difference being the grinding wheel, is of the “pencil” or small diameter cylindrical type, set in a router spindle to get the highest cutting speed (27000 RPM for my router), a Dremel type rotary…

A few years back I needed a tool for cutting narrow grooves for circlips and E-clips. My first approach was to try grinding a 6 mm square piece of HSS tool steel to form a very narrow parting tool to cut the groove. Using just a bench grinder to do this proved to be very difficult as it was very difficult to control the final width of the tip and try to put on some side clearance proved almost impossible without weakening the tip. After a few unsuccessful attempts it occurred to me that most of the circlips that I were using were about the same thickness as a hacksaw blade. A quick check with a pair of calipers indicated the the hacksaw blade was in fact 0.7 mm and…

In September 1958, I had scarcely laid eyes, let alone hands, on a lathe, when I entered the Training School of the Rolls Royce Oil Engine Division, at the Sentinel Works in Shrewsbury. Over the next six months that situation changed, and I operated, with varying degrees of success, all types in the Training school. This period did not make me a skilled machinist, nor have I ever made my living from being a machinist, so make no claim to being an expert. Of late there have a number of posts on the Model Engineer and Model Engineers' Workshop Forum from newcomers to the hobby, asking basic questions. I hope that at least some of the questions may be answered by some illustrations, and words, from the notes provided. My…

Some time ago, Alan Jackson did a transplant onto his Tom Senior M1 milling machine and wrote up his work in the January 2020 edition of Model Engineers’ Workshop, ref.1. In this article, the receiving machine is the Junior model Tom Senior mill, the design of which imposes some important limitations on what can be done with a machine graft of this kind onto the smaller model. Background story Alan's conversion is inspired. In essence it combines the function of vertical and horizontal milling machines into one unified whole, and it was one of several factors that led me to thinking about converting my own machine. Adam Booth in his superbly equipped US workshop (from where he produces many YouTube videos of his work under his brand name Aborn79) has…

One project I made by the lost wax method was a silver brooch depicting a bicycle. The wax pattern was made from a thin sheet of wax on which the outline of the bicycle was drawn. Photograph 32 shows one of the trials. To draw the outline a wax dispensing pen was made, photos 33 and 34 and fig. 3. The “nib” was an old hypodermic needle which was a push fit on the manufactured “pen”. The latter had a reservoir at the top from which protruded a tube through which air was blown to force the molten wax out of the nib at the desired rate. The body of the pen was made from copper which was bored to take the heating element of an electric soldering iron, the…

In the previous instalment we looked at composition and framing your images then moved onto backgrounds. I keep several items specifically to use as backgrounds or bases for photographs. Some recent additions to my ‘background’ collection have been relatively neutral, but textured, wall and floor tiles with matt finishes. The matt finish is definitely a good idea, photo 1 shows a lathe stop on my ‘surface plate’, which is a piece of granite composite kitchen worktop; while it is flat enough for my practical needs and makes a good solid surface to measuring and marking out, the high gloss results in lots of distracting reflections. Wood effect worktops with a less shiny finish often work well. People often choose a cutting mat as a background. The 1cm grid in photo…

AFTER FIFTY YEARS, and despite ingenious alternatives,. the poppet valve has established itself as the standard valve for four-stroke i.c. engines. Its construction and servicing inevitably concern in some degree all who have to do with such enginesmotorcyclists, car owners, mechanics and engineers. Though the causes of valve (and seat) trouble may be various and often interacting, all stem broadly from the following; the heat to which the valve is subjected; the hammering it receives along with the seating font the spring action on closing; wear of stem and guide; incorrect servicing or adjustment. Valves run very hot. exhausts in particular. They scale on the heads, burn on the faces. Added to this, the “skin” acquires a burnished impacted structure from hammering, different from the clean precision before use. In…

Marking out is yet another dying art, due to the widespread use of CNC machines in industry. However, we will keep it alive! Most marking out is done on a surface plate, using a height gauge with the workpiece upright against an angle plate (or resting on a previously-machined surface) and the surface of the workpiece coated in blue marking-out fluid applied by brush or spray, photo 1. A surface plate which is 12” or BOOmrn square –or larger – is ideal, as sometimes you will want to place a sizeable rotary table or angle-plate on it (holding the workpiece) and still have plenty of room to work with the height gauge. Excellent surface plates and height gauges can be had second hand on eBay; they can also be found…

Join us on the Forum! The forum at www.model-engineer.co.uk is one of the biggest and friendliest online forums for model and hobby engineering – and it's free to be part of it! The web site also includes a digital archive right back to issue one of MEW, available to digital subscribers. During the Covid-19 lockdowns the forum provided an invaluable way for hobbyists to keep in touch with each other. If you have questions to ask, ideas to share or just want to chat about workshop topics, come and join in. Write for us! Model Engineers’ Workshop is a magazine that has almost all of its content written by its readers; from beginners recounting their first experiences of the hobby to old hands passing on the wisdom of many years…

Royal Engineers Dear Neil, I enjoyed your editorial in MEW 323. My Father was also a ‘Don-R’ in the RE's. He went to Egypt via Cape Town, served right across North Africa. Was attached to the American army, landed at Salerno (Italy) with them, (he saw Vesuvius erupting in 1944), eventually to end the war in Leverkusen (Germany) where he met my Mum. The rest is history. Please find a photo attached of my dad at a mobile workshop somewhere in Germany with Fritz the dog on the tank. I also served in the Sappers some 25 years later. Pete Summerscales, by email Watches Dear Neil, watches, may I recommend “wristwatch_revival” on YouTube? The person is Marshall Sutcliffe, very practical and down to earth approach, knows his skills and tools.…