Worlds nicest Variac

The first bit of the build was to create a case for the variac. I thought it looked really good and it would be a shame to stick it in a metal box. Decided to keep it on display by casing it in perspex. Had lots of small taps and stainless allen key bolts hanging around so decided to bolt it together rather than glue. Trent Plastics was found (eBay again), a supply of many types of plastic sheet and tube. They can supply cut to size so saved me hours of measuring and cutting. The main tube is 250mm diameter 6mm wall, the top holds all the weight so I went for 8mm thick clear perspex. The base is 5mm thick in black cos I thought the base would get scratched pretty quick so clear was probably not a good idea. The next pic shows Variac fitted to top plate and top plate bolted to main tube. Bolts are M3 so not a lot of room for error when drilling holes in the main tube.








After drilling and tapping to fit the base I decided to fabricate some handles which would be fitted to the 4 bolts that mount the Variac to the top plate which meant there would be no stress to the perspex when lifting. Also drilled some vent holes in the base and the top plate, small feet on the base provides clearance for air to enter circulate passed the coils and then out through vent holes in the top plate. Drilled 12mm holes for retro style 20amp switch and 3 10.7mm holes for the glands. The glands have a 12mm 1.5 tpi thread so another ebay purchase was required for the tap and 10.7mm drill bit.







Well happy with the result, handles are solid 16mm aluminium rod, I milled the ends so the M8 x 70 bolts sit nice.







Vent holes are 12mm, you have to go quite slow when drilling otherwise the perspex just melts. Worked well clearing the swarf regularly off the bit. May need more vents, just have to see how it goes.







Switch sits in another 12mm hole. Room for extra vent holes either side of the switch if needed.







Here you can see the 3 glands. One will be 240v mains in, one will be 240v out via switch (may use for quench fan) the other is variable voltage out via the variac. Wiring is the next job.


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