Innholdsfortegnelse for May 2023 i Model Engineer & Workshop

The only Constant is Change! By its nature, model and hobby engineering is an experimental hobby. It attracts creative thinkers with open minds. We are always repurposing things, stretching the capabilities of our equipment and looking for ways to make things, better, simpler or more flexible. When I became editor, it was my assumption that the hobby was fairly static; how wrong I was. For example, around then inverter controlled motors were becoming more affordable and it seemed everyone was fitting them to their machine (including me!) This issue sees a review of a stereolithography or ‘resin’ 3D printer. It seems remarkable that this is the first time this technology has appeared in MEW, yet it’s only about tens years since such machines became a practical option for a hobby…

I first learned how to use these cunning devices while spending 3 months in a machine shop during a sandwich degree course. It was in the days before digital readouts (DROs) were common. If high-accuracy holepositioning was required, the only alternatives were a jig-boring machine or the use of toolmakers’ buttons. Imperial button sets can be found in sizes of 0.3”, 0.4” and 0.5”. I believe that metric buttons were also made. Photograph 1 shows my set of 0.5”D buttons. Buttons are finely ground and polished, with the diameter being accurate to 0.0001” or better. Having said that, it is pretty easy to make a usable set oneself from silver steel. The dished end goes against the workpiece. The central hole is substantially larger than the outside diameter of the…

Wood Screws Dear Neil, Unfortunately, I cannot help Sid Rawlings with his quest for details of screw manufacturing machinery, but his mail in Scribe a Line, in MEW issue No 323, prompted me check in the tin of old wood screws that I inherited from my dad and I came up with the selection of screws shown in the picture. I think these are at least 90 years old but what would they be used for? Such stubby screws would provide little grip as the thread penetration into the stock would be minimal. Perhaps the use of modern adhesives has replaced them. Gone are the days when every DIYer had a cardboard ‘gross' box of 1 ½ inch, No 8 steel countersunk screws for general purpose wood work and, for…

TIP OF THE Month WINNER! A new approach to getting tool sharpening angles right This month’s winner is lain Downs who has come up with a novel approach to achieving accurate grinding and honing angles. I’ve attached some photos for my approach to precision grinding…. Without a D Bit cutter or similar. In essence I make a pattern in Onshape, print it and use it to hold a toolbit at various strange angles. The two most interesting ones are the end thinner (used to take a 0.5mm junior hacksaw blade down to 0.3mm at the end) and the one for honing a threading tool which has both a 30 degree and a 15 degree angle on it. We have £30 in gift vouchers courtesy of engineering suppliers Chester Machine Tools…

Reading the fantastic article by Geoff Andrews in MEW issue 321 on modifications made to his mini lathe, one of the photos reminded me of an accessory I made for my Boxford lathe a while ago. This is one of those items that doesn’t get used all the time but when it does you wonder how you managed without it. Though it is made fora Boxford I’m sure it can be modified fora lot of other machines. The fixture was made quite hurriedly at the time for a job of batch parts using bits of stock found in the scrap bin, so it was made around these rather than the machine itself. Fair to say it has worked out quite well and serves its purpose admirably. You will also see…

The King I refer to was the king of my workshop, approximately ninety-four years old. Through its life it has had many changes. It started life as a Progress No. 1 Bench Drill in the old blacksmiths shop at East Midlands Gas Board, and when the Blacksmith retired it was going for scrap for the humongous fee often pounds, which was a lot of money in the seventies. You could have a real good night on the town for a tenner. That started our life together for over fifty years and it did many things that it was not designed to do, photo 1. The first thing I changed was the three-phase motor to a single phase ½ hp washing machine motor, it was what I had handy at the…

Notes on Drill Sharpening Some adjustments are possible by turning the drill (using sideways movement of the cam). Ideally the result is good if the cutting edge of the drill is horizontal when just touching the wheel at the end of the sharpening process. This is function of the amount of material to remove, if the hand sharpening (always necessary before the machine one, see my article in MEW issue 245) has been well done, just a few tenth of mm are to be removed and don’t hesitate to grind off the heel as the heel is of no use, takes time to grind and wears the sharpening wheel for nothing (the heel is the bete noir for drill sharpening). If ever the cutting edge is lower than horizontal, the…

What is Sterolithography? Stereolithography uses patterns of ultra-violet light to set thin layers of a photosensitive polymer (photopolymer, commonly called UV resin or just resin) to gradually build up a three-dimensional object. It is comparable to 3D printing using fused filament deposition, a process that most readers will be aware of, even if they haven’t used it themselves, which builds up layers of an object by extruding a fine bead of heat-softened plastic Stereolithography or SLA printing was first patented in 1986, so it predates fused-filament deposition (FFD) printing by a couple of decades. The complex arrangements, especially the UV lasers used to set the resin and the need for large tanks of photopolymer made the early systems expensive and unsuitable for benchtop use. Around ten years ago, relatively affordable…

The forum has been somewhat abuzz recently on the topic of wallcharts, look-up tables and so on. The subject of finding space to mount them has also been raised, and of late, my eyesight has made using A2 posters more readily readable than the A3 I was previously happy with. The pictures show several I make frequent call upon, and I spent time pondering where they could be hung, once appropriately enlarged and laminated. The answer eventually hit me: not only to treat them as looseleaf pages, (flipping through to the one currently needed) but use the 3-ring mechanism also to suspend them on the outside of my measuring tools cupboard. The mechanism was separated from its unoffending parent binder by drilling out the two attachment rivets, the resulting holes…

BEGINNERS WORKSHOP These articles by Geometer (Ian Bradley) were written about half a century ago. While they contain much good advice, they also contain references to things that may be out of date or describe practices or materials that we would not use today either because much better ways are available offer safety reasons. These articles are offered fortheir historic interest and because they may inspire more modern approaches as well as reminding us how our hobby was practiced in the past. ABILITY to cut metals and resistance to wear are characteristics of certain steels which it is often essential to exploit, either for cutting tools or special components. Making a choice, one is guided by the following in regard to the three main groups of steels: (1) mild steels…

Magazines Hobby engineering is well supported by specialist magazines, some of which have very long pedigrees indeed. Model Engineer magazine dates back to 1898! A subscription to one or more model engineering magazines is an excellent way to keep informed about your hobby and an excellent complement to online forums. Model Engineers’ Workshop You hold a copy in your hands! (Unless you are reading this on a scree…) First published in 1990, Model Engineers’ Workshop was set up as a sister magazine to ME with a focus more on tools and workshop techniques, rather than engineering models. Catering for all aspects of hobby engineering from modelling to car and bike restoration the magazine covers traditional workshop machines such as lathes, grinders and milling machines but in recent years has widened…