Saturday, July 26, 2008

Things moving along well, but still working on the rails

Well with the first rail sort of done (discovered AFTER i ground it that the damn kid used it as a pry bar for his car, and it has a noticeable curve in it. Will have to grind to match the second one), I am starting on the second. As can be seen, the 9" grinder from hell does a great job on getting it close (also does a great job on my poor arms), and by checking every now and then with a protractor, I can keep it almost dead on. After I finished grinding it with the 9" monster, I checked it and found it was so close I could probably use it as is and it would work OK. I however decided not to push my luck and instead grind it down to a nice exact finish.

After sitting there and grinding away with the jury rigged set up, another thing flashed through my mind. It takes a long time to do each rail, and the constant turning of the cross slide handle wears out the hands really fast. So, at that point I decided that I would make the unit power fed since the concept and creation seems to work well. I did some digging and found a company that sells DC geared motors with over 8ft pounds torque running at 50 RPM. While 50 RPM sounds low, I figured that in most places while grinding I was probably turning the handle at about 3 RPM if I was lucky, so the fact they sell a speed controller for the motor was a huge bonus.


Now this would make life a lot easier for the finished product, but what about now. Well, I grabbed my cordless drill and clamped it on one of the cross slides end shafts. Boy this makes it a whole lot easier.

I will, once I have most of the fabrication done, get the gear motor, speed control and power supply for it. All in all the price tag will be about $200.00 (since shipping to Canada from the states really sucks), but will be more than worth it. The speed control has wires to start stop the motor, as well as to reverse the direction. This way, using adjustable limit switches and some timing circuitry, I should be able to have it automatically run back and forth over the piece being ground for a hands free operation. I will not put a power feed on the front/back feed, as that's a bit too expensive and would require to much control safety checking. I wont put one on the height adjustment either, as that would be pointless.

Once I get the two rails finished and mounted, I can start work on the lead screw for the height adjustment. I could buy ready made lead screws, but will try doing a 1/2" one myself (Should be fun, the first thread I ever cut on a lathe and it will be a 1/2" ACME thread 2 feet long lol). Once I get the rails mounted I will update this blog.

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