Engines > From Plans
Another MEM Corliss (in .40 scale)
gbritnell:
Since the MEM Corliss drawings were posted quite some time back I had mentioned that it would be on my to-do list. Well I got started on it this morning but not in the usual fashion. I took the smallest screw size on the drawings, 0-80, and scaled it to M1.0 x .25. The scale factor came out to a little less than .40 but I rounded it off and went with that number.
The majority of the screws on the full sized model are 1/8 (5-40) these work out to M1.2 x .25. The cylinder is made from 12L14 steel. I trued it to size then drilled and bored the bore, .45 inch.
gbritnell:
The porting from the valve chamber on the full sized model is drilled with a 1/16th drill. With my scale factor this came out to .025. I laid out the drawing to see exactly how the porting looked. Not having a center drill long enough or small enough I went with my only option. I drilled out a piece of 3/16 brass rod for the .025 diameter drill. I turned a 15 degree taper on the nose to match the port angle. The drill was cleaned up and Loctited into the brass. I left only enough sticking out to break through into the cylinder. Before using it I pushed on it with my fingernail and it seemed quite rigid.
My mill only goes up to 2600 rpm so that's the best I can do for this small drill. I set the cylinder on 15 degrees and picked up the center of the valve hole. I cranked up the spindle and very lightly touched the drill to the bottom of the valve hole. Once I felt that it had centered itself I felt my way through the metal into the cylinder. There are 5 holes spaced .037 apart. When I got done the holes looked quite uniform and in line. Whew!!!! I would hate to have put 8 hours into this cylinder only to have the small drill wander or break.
b.lindsey:
Another tiny project to look forward to. The penny shows how small that cylinder is....wow. I'm hooked already George!!
Bill
crueby:
Oh my!! What a wonderful project! As usual, will be watching this one with a prop under my chin to limit the drooling.
:popcorn: :popcorn: :popcorn: :popcorn:
Any chance I can get you to do a teensy Marion shovel to fit in the bucket on mine? :Lol:
:cheers:
Craig DeShong:
The start of another amazing project. Can't wait to see the future installments. :popcorn:
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