Innholdsfortegnelse for April 2024 i Model Engineer & Workshop

Inverter Protection Back in 2013 I fitted a variable frequency drive (VFD) to my Mini Lathe (a Clarke CL300M), and ever since I've felt that the VFD itself deserves rather better protection from flying swarf and the like. The answer is obviously some sort of enclosure, and my thought was that the ideal would have plenty of room around it, combined with a louvred top for ventilation, and an open bottom for easy access for the cabling and to allow anything that does get in to drop out. It should also have a clear front so that I can see the display, which is set up to read out lathe speed and also shows any error codes, should the motor overheat or there be another issue. I had some samples…

“The past is a foreign country; they do things differently there.” This phrase came to mind when standing in the Great Western Railway drawing office last week looking up at the vaulted roof. Yes, it's still there, now an English Heritage reference library. I visited to breathe in the ambience of the office where Stars, Castles and Kings were designed. The beams supporting the roof purlins are made from broad gauge bridge rail, bent at the works in 1904 to the desired radius. Could UK engineering shops today replicate this feat? Since my last article on the fly press (MEW 211) I have made several press tools and dies which have worked really well and I hope that they give you a few ideas for your own projects. I'll let…

It all started with a left over off-cut of ¼ inch silver steel rod. If put in the “come-in-handy” draw it would languish there for twelve months or more until the day came when it would be found to be just too short to be used for the project then in need of it. I therefore felt it needed using up. Older readers will I am sure remember an item called a “bell centre finder”, a hand tool for spotting the centre on the end of bar stock. Fairly accurate, simple to use and speedy in operation. Since a picture “tells a thousand words” I refer you to photo 1, 2 and 3 for illustration. To use, the hollow bell is placed on the end of the piece of bar…

Having found a need for a vertical slide to fit the compound slide on my watchmaker's lathe and seen their rarity and price, I decided to have a go at making my own, photo 1. I found a Chinese version on sale that looked like a reasonable starting point. So, I proceeded to draw some plans with the idea that the design must include a spindle that could be driven by a rotary tool flexible drive. This seemed like a bright idea as it would obviate the need for pulleys and belts. I noticed that the Chinese pulley version had a reversible spindle which allowed for the driven end to be chosen dependent on its orientation. I came to the decision to make my spindle double ended and consequently fixed.…

Fitting digital scales and a readout display is clearly a priority for many milling machine owners, and this was my intention for my mill/drill. At the time, quite a few years ago, capacitive scale units were vastly cheaper than any superior alternative, so this was the route followed. Of course, it proved more challenging than expected. Despite the undoubted utility and good value of these familiar oriental capacitive digital scales, problems can range from positional jitter, poor feel and short battery life, through to malfunction when connected to the readout (display) unit. My eventual experience has been very good after some vexing problems. With some lateral thinking and considerable work, I now have very reliable operation. Though describing how this was achieved is primarily about the electronics, it is hoped…

3D printing Experiences Hi Neil, for hobby machinists and for those of us who are older the often included 3D printed examples of unrelated objects are of little interest or indeed have doubtful relevance to whatever is going on in the workshop. With the falling prices of a basic FDM machine, I purchased a Creality Ender 3 S1 about a year ago and have already pushed a Kg of PLA filament through it. As a long time 3D modelling user I find I can create a model quickly and have it in the printer in 10 mins or so, leaving it to chug away while I go on with something else or leave it to print overnight. For those not already adept at 3D modelling a further barrier for capitalizing…

The magazine, which covers every aspect of life from the 1930s through to the present day, becomes the 25th regular title in the Lincolnshire-based publisher's portfolio of publications. “We are delighted to welcome Best of British Magazine into the Mortons Media Group family,” said Mortons’ publishing director Dan Savage. “Best of British has a rich legacy, and we are committed to building on that foundation, delivering engaging content to their readers and creating new opportunities for advertisers.” The UK's premier nostalgia and heritage magazine, Best of British celebrates classic entertainment, transport, food and drink, and the great British countryside. Regular features include Treasures in the Attic – a look at recently uncovered antiques and collectables, Postcard from… which casts a spotlight on a British town or city to visit or…

Ionized Air as an Alternative to Cutting Fluids Disposal of used cutting fluids causes significant environmental contamination. Global annual consumption of cutting fluids is estimated to exceed 2 billion liters - although the actual amount of cutting fluids waste is assumed to be up to 10 times higher, as most fluids are diluted before their use. Cutting fluid treatment and their release to the environment leads to significant oxygen depletion and nutrient destruction in surface waters. Aurion technology uses ionized air which generates an electrochemical process resulting in electron loss and atomic level transformation of the Aurion gas medium at the cutting surface. The electrochemical process acts as a dry lubricant in the cutting process, penetrating the cutting zone and optimising the interaction between the tool edge and the workpiece.…

Using these increased PCD gears also introduced another problem. A standard 0.5 MOD worm will not mesh with these gears. To get around this the worm also needs to have a larger pitch due to the greater distance between the gear teeth, plus the effect of the helix angle. A standard 0.5 MOD worm has a pitch of 1.5708mm, but the worm to mesh with the 10-tooth helical gear needs to have a pitch of 1.729mm. Trying to set-up a gear train to cut this pitch on my Maximat Super 11 proved at the time to be a fruitless exercise and in the end I settled for a standard 1.75mm pitch, but cutting the worm slightly deeper. This introduces a pitch error of approximately + 0.02mm. This does produce an…

Last month I introduced readers to the headquarters of the SMEE, Marshall House, to conclude this month I'm going to share photos of some of the machinery in the society's workshops. Before I do this, I'd like to thank SMEE Vice Chairman Elliot Hirst, who got in touch with a few thoughts. First the loco by ‘Uncle’ Jim Crebbin in the Lecture Room is actually Aldington, later known as Conversion, not Cosmo Bonsor – the latter normally lives safe in a box and appeared at MMEX last year. Also, the Maudsley Type Table engine was built by Robert S Charsley, photo 1. In 2022. this engine was restored to proper working condition by SMEE Chairman, Allen Berman, photo 2. He took a ‘conservation’ approach cleaning and restoring parts where possible…

FOR LIGHT FLAT belt drives, as may be used in small workshops, commercial types of fastener are usually too large and heavy, fitting badly on the curvature of small pulleys and tending to weaken the belts at positions where they are joined. Generally, better results are obtained-partieularly with leather belts-by employing a chamfered and stitched joint or a type of small hinge which can be made to suit any width of belt. If time permits, much of the initial stretch can be taken out of a leather belt by attaching to a beam and hanging a weight on the end for several days. If height is wanting or the belt is long it can pass over the Beam, packed to avoid sharp edges, and support a pair of weights. The…

TIP OF THE MONTH WINNER! Extending WiFi Range This month's winner is Ian Richmond, who recommends a way for getting a wifi signal around old or large houses. (Thanks also to Richard Taunton for the first photo). The writer of the article on resin printers suffered from wifi range limitations to his workshop (August 23 issue). My house rambles with the router at one end. Wifi is not working in some rooms. I use AV600 Powerline adaptors or similar. These are mains plugs with an ethernet port and come in pairs. One is plugged into a mains socket near to the router and linked to it with an ethernet cable. In the workshop the other plug is again plugged into a mains socket and linked to your PC with an…

“One of the attractive features of model engineering as a hobby is the comparative lack of competitiveness as a result of which no one is obliged to please anyone but himself. Long may it continue.” (Geo. H. Thomas, Ref. 7) The above words greatly pleased me when I came upon them recently in ‘The model engineers workshop manual’ since I feel that this philosophy is particularly apt for the present project. It has already been explained why micro-milling was important for my aim of building a miniature steam turbine. As will be discussed later, four-axis cnc micromilling would undoubtedly have been the best way to cut turbine blades and, after building this equipment, I saw that it was possible to buy on Ebay, for just a few hundred pounds, a…

It is an easy enough task to machine a disc of some required diameter from sheet material, if you know it will need or can have some holes in it. It is just a matter of roughly cutting out a piece of the sheet to a larger approximate circle, drilling the holes (maybe just a centre hole), mounting the roughed-out disc in the lathe with some sort of mandrel or holding device using the drilled hole or holes, and turning the disc to the required diameter. But if the disc has to be hole free, it is a more difficult matter. What I wanted was some sort of arrangement whereby I could machine discs of up to about 200mm diameter from metal or plastic sheet material of up to maybe…