I am making the Howell V-twin and have a question concerning machining the interior of the block. Does anyone have any suggestions for cutting the interior radius in the area just under where the cylinders penetrate the block?
How deep is the groove in there. You could do it on the lathe with an internal grooving tool. Can be insert type or you could grind one of your own. I have also made internal grooves using the mill, rotary table, and a keyway cutter.
If you look at Jerry's pictures in the Gallery section you can see that the internal area of the block under the 45 degree areas where the cylinders penetrate were machined in a radius that is deeper than the radius bored perpendicular to the block for the crankshaft. The tool would have to cut an internal diameter greater than the entry hole. I have an internal threading tool but I do not think it would be large enough to cut to those dimensions. Sounds like a purpose-built tool.
From what I see the cylindedr bores are straight thru. I dont see any machine work under the bores. The cylinder hole on the left looks like there is something fancy going on there but if you look thru the block at the cylinder hole on the right it looks like it is straight thru to the recessed area in the block.
Guess I would need to review the drawings. Does the drawing show some work in that area?
I don't see anything in the drawings but the impression I got from Jerry's photo's was that he had machined a radius inside the block that was larger than the radius for the crank openings. It may be just an optical illusion.