Tabla de contenidos para December 2022 en Model Engineer & Workshop

In this issue you will find my report from the Midlands Model Engineering Exhibition. I'm now based In South Wales, and it was a reasonable prospect to travel to and from the exhibition on the day, fortunately in a very fuel-efficient car. As well as seeing the exhibition, I had another important task to complete on the day, meeting up with Ian Johnson, the previous winner of the Stevenson Trophy. I hadn't met Ian before as the complications of ‘covid travel’ got in the way, but fortunately the winner before Ian, Michael Cox, coincidentally lives fairly close to Ian and had been able to make the handover. Chatting to Ian I found out that the focus of his hobby is not so much on models as on full size items.…

The main advantages that I saw were the fixed nature of the work holding and the ability to adjust the intended drill position via the vice slide screws. The vice in position on the pillar drill table is shown in photol At the time of purchase I was making electronic printed circuit boards (PCBs) when the standard circuit components had pins at a 0,1 inch pitch, so I made new screws that made moving the work by the required 0.1 inch an easy operation. Both ¾ Whit and ¾ UNC have 10 TPI (threads per inch) so utilising either would make the move one revolution of the screw. Next came the requirement for an even more accurately placed hole as I found that the sliding jaw was lifting on tightening…

TAPERS and light driving or force fits are common ways of securing components firm ly to shafts and other parts-yet admitting of dismantling when required. Normally, no problems are encountered in assembling, as there is usually a nut, setscrew, or series of such, by which parts can be pulled together. It is their dismantling which occasions difficulty-or even damage, if the right methods and tools are not employed. Tools with which dismantling is effected are called pullers, drags, or drawers: and take a variety of forms. Some components can be dismantled with universal tools covering a range of sixes, while others demand special tools for each purpose. The common type ot puller. A, consists of a beam carrying a pressure screw and slotted for a pair of jaws which can…

I'd like to start with a book recommendation for those who are starting out in our hobby. The Amateur's Lathe by L H Sparey is still one of the best books covering lathe work, despite it being written in 1948. You'll find it hard to find the recommended lard oil or whale oil today, and there is no mention of tools with replaceable carbide tips, but the book does cover the basics of turning very well. I remember from many years ago that when Martin Evans started a new locomotive construction series, several readers would do their best to keep up with Martin, so that when the last article in the series was published, they were very close to finishing their models. They clearly did not work or have a…

MMEX is organised by Meridienne Exhibitions, and for them this was something of a bittersweet event due to the relatively recent passing of Chris Deith, the originator of the exhibition. His contribution to the hobby was marked by a new trophy, The Chris Deith Memorial Trophy, awarded to the best overall entry in the competition classes. The trophy was award to Mike Tull for his ¼ scale Working Model of Bristol Mercury MK8 9 Cylinder Supercharged Radial Engine. Mike actually made two of these engines, and photo 1 shows the ‘exploded’ version which came third in the class in which his trophy winning example came first. Stepping back for a moment, on arriving at the Warwickshire Event Centre, it was clear the show had attracted a good audience by the…

Parallel bevels are attractive to model engineers because they can be made without the large and expensive machines used for their fully formed equivalents. The two types of bevels are shown in photo 1, with the larger bevels being fully-formed commercial products. However, parallel bevels are generally inferior in terms of smooth running and backlash. The latter persists even when they are tightly meshed. The revised geometry developed in “Bobs Better Bevels” improves this, but for technical reasons the development was initially on 1:1 bevels and then largely on 2:1 bevels. Bevels having a higher ratio were noticeably more difficult to manufacture and as 2:1 became 3:1 then 4:1, I realised that some revisions in the manufacturing sequence were required. Photograph 2 shows blanks and finish machined 4:1 parallel bevels.…

TIP OF THE MONTH WINNER! A Bandsaw Jaw Modification This month's winner is Gary Wooding from Coventry, with a tip that is a nice complement to the bandsaw article elsewhere in this issue. Many users of the ubiquitous 4x6 bandsaw have discovered that the movable vice jaw tends to rotate when trying to hold short length workpieces. This tip completely solves this problem and requires no changes to any part of the bandsaw at all. It's just a metal plate the same size as the fixed vice jaw, about 6mm thick. I used some aluminium sheet. A hole is drilled and tapped near one end to accept a suitable length of threaded rod that is used as a jack. I used M10. That's it. The plate is positioned against the…

Over the years, our daughter has given me many older copies of Model Engineer. Needing space, they were earmarked to be sent to a new home. Before passing them on to someone else, I read through them, looking for articles that might be of interest. Among the articles was one by the late Peter Spenlove-Spenlove, on turning steep tapers between centres. He had converted normal centres to take a ball bearing, which would allow a greater angular offset for turning steep tapers, on short workpieces, between centres. These are used instead of typical taper-tipped centres, running in holes drilled with centre drills and with plenty of lubrication and are much more tolerant of the required ‘misalignment’ of headstock and tailstock. Since it seemed a Good Idea at the time, I…

Rust Dear Neil, the article on rust and rust removal (MEW 320) is something everyone should know, I have salvaged tools and machine parts from watchmaker size to really big using either malt vinegar or, latterly, proprietary lime-scale remover (less smelly) to remove rust. Your article warns that de-rusted parts should be dried well and oiled to prevent re-rusting but one of the causes of this is that the de-rust solution is acid and, especially with organic acids which may leave a solid residue even when dried, it advisable to neutralise the acid used by giving a bath in washing soda or bicarbonate of soda solution (one teaspoon per litre) after rinsing, then dry in an oven. Incidentally, I have frequently used brickwork cleaner (20% hydrochloric acid) to remove zinc…

Whilst the production of swarf, whether chips or long spring-like threads, can be treated as satisfying in itself it is far more rewarding if the swarf produced is the product of the making a “something”. The item described is an “attachment” for use on lathes that have a large threaded central stud or bolt to clamp down the tool post or tool holder. Its use is to simplify the holding and drilling holes in rod or tube. No units of measurement are specified, and no accuracy of the “half a gnats” variety is required. In fact not even any dimensions shall be supplied. So you shall also have to supply a certain amount of design, photo 1. What is being made is similar, in use and application, to that of…