Saturday, March 10, 2012

Machine shop 001 - remedial edition

I want to build a metal shaper... from scratch.

It will be small, made from the stuff I can get locally, and kinda wimpy as a result. No castings, no 50 pound bull gear with a slot, yoke, etc...

I'm going to drive a pair of 7/8" screws with a gear reduced drive... this will provide the necessary force to drive a cutting tool in a planing motion through a piece of steel or aluminum.  (I did an excel sheet to get the numbers right... I was surprised at how little actual cross section there is in a planing operation... which makes it feasible to do it this way).

I got some tools in motion today. I have managed to mount a 6"x6" 1/4" aluminum plate to one side of a 6" Lazy Susan. I drilled and tapped holes at 10/24 to allow hex cap screws to hold it in place.  Now I just need to trim the screws so they don't protrude out the other side of the plate. 8)

Next up will be figuring out some arraignment whereby a 4" vise can bolted to the plate via it's mounting slots, so that I can align the center of the work piece with the center of rotation.

Once that is done, then I should be able to use this to cut a few gears out of aluminum plate. I want to make a a pair of 2" radius gears (one for each screw), and a 1/2" radius gear to be driven by the electric screw driver.

5 inch pounds of torque from the screw driver, should result in about 314 pounds of thrust at the business end of the screws.  8)

My backup plan is to make worm gears if there turns out to be insufficient torque available.

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