Regulator for Bulgarian or "Bulgarian" chain sharpening

Like any resident of the village, I spend quite a lot of time on preparing firewood. And in order to saw them, every owner living in the village has a gasoline saw, and I also have an electric saw in reserve. Periodically, they need to sharpen the chain. At first I did it manually, using a special file, but this is not an easy task, my hands get tired quickly, and it doesn’t work out very smoothly. Several times he drove chains to the city, ground on a special machine. But this business is paid, and the grinder does not always work. It is clear that you cannot sharpen a chain from a chainsaw on an ordinary grinder. I tried to grind it with a grinder, but there are such high revolutions that the teeth simply burn out, and do not grind.

And I remembered that somewhere in the barn I had an old LATR - Laboratory Auto Transformer Adjustable. And in fact, he went, looked in the scrap metal and I dug up this thing. It turned out that she was working! Although rusty, although released in 1967, it says "Made in the USSR" on it, which means that the thing is eternal.




We connect the input terminals to the 220V network, we hang a socket on the output. We install about 90 Volts at the output of the autotransformer, clamp the grinder into a vice, and turn it on. The disc of the grinder rotates slowly, 1500 ... 2000 rpm \ min. Just what you need! We take the chain, and gently press the teeth of the chain to the disc of the grinder. First, one side of the teeth, then the other. We get a wonderful semicircular sharpening, nothing burns, everything is perfectly sharpened. The width of the disc of the grinder is exactly equal to the width of the groove at the teeth of the chain. In an hour I sharpened five chains, a dozen drills and ... scissors that came to hand.



For those who have just thought about the dimer, I’ll answer - I tried it, it doesn’t fit. The grinder works, but it buzzes, and the disk turns in jerks and it is very difficult to catch the necessary speed. This is evident because the output of the dimer is not a sinusoid, but pulse packets, which is quite suitable for incandescent lamps, but bad for motors. In addition, I have a grinder of 650 watts, and I need a dimer for it at least 1000 watts. Such a pleasure is expensive, and LATR in the barn has long been free ....