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| kvom:
Made the cams: I turned some brass rod down to .780" and drilled the center hole, then mounted it in the rotary table to mill the rest of the profile and drill the mounting holes. Then it was back to the lathe to part off two "slices". Finally I milled the cams to the desired thickness. Here they are mounted on the driveshaft: The dimensions given result in a very precise, tight fit. To get the screws to line up with the taped holes in the shaft I needed to file the center hole slightly to give some wiggle room. I also think a #43 drill for the mounting holes would be preferable to the #44. One issue to resolve at assembly time is the angle the crank pin needs relative to the cam lobes. The cam nearest the end drives the input valve, so I'm guessing that the valve should start to open somewhat just before TDC. Comments? |
| CrewCab:
Excellent work Kirk :beer: The flywheel is looking good and nice use of the mill ............... plus Marv's input of course, well done sir :headbang: About the Cam's :scratch: ................... yes. it looks like the inlet valve will begin to open a little over 11o before TDC, however I seem to be missing something in the drawings ............. is there a dimension short ............. how do you locate the intersection of the 20o angle with the .78" diameter, obviously once that is correctly machined the .68" diameter is straightforward to machine .................. not a criticism by any means Kirk, perhaps just my ageing brain cell's refusing to co-operate . Again ................. top class work mate :bow: CC |
| kvom:
The straight sides are .340 from the center, so I move the x-axis +/- .340 plus the radius of the cutter, rotate the table +/- 10 degrees, and cut straight with the y axis. Then for the .340 radius portion, I set the x-axis to 0, rotab to 0 degrees, and touch the endmill side flutes to the work. Then in theory I just need to move the y-axis in .050" and rotate the table. In practice I cut in .045" first and measured the diameter before taking the final cut. The crank pin can be installed at any angle to the cams. TDC should occur then the pin is directly below the cylinder's axis, so my question is whether the valve should open before, at, or after TDC? |
| CrewCab:
--- Quote from: kvom on October 10, 2009, 02:26:39 PM ---The straight sides are .340 from the center, --- End quote --- Got it .... (an Eureka moment for my grey matter)...... :med: ............... thanks Kirk, looking forward to the rest :bow: CC |
| bogstandard:
If you go to here, how to cut the cams on the RT is explained step by step. http://lineymachine.googlepages.com/halobuildinginformation Bogs |
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