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Minh,
I feel your pain on the crankshaft. I "learned" 2 times on HOW NOT TO DO IT! Then on the third try, using advice from this forum, I succeeded. When doing cranks from a solid round, make biscuits to snugly fit between the webs. Then when you push the live tailstock center in to hold it, the biscuits take up the pressure and you shouldn't have problems.
Grasshopper
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Minh,
I hope this comes through for you. Bazmak made a Chuck Fellows compressed air at twice the size of the measurements and I did the same. I wasn't making gears at that time and I adapted a cogged belt drive system with an idler for tension. Hope the plans open up for you. I hope another attachment opens and shows the V8 running.

Grasshopper
 

Attachments

  • Cirrus V8 Plans.doc
    4.5 MB
I found the price of the long taps to be " not worth it" so I took a piece of drill rod/silver steel and drilled and reamed a hole in it in the lathe. I put the tap in the tailstock of the lathe in a chuck and gave it a good push to press it in. Think you call that a good sliding fit. Haha!! Then I turned down the diameter of the rod on the tap end to .1875 or something like that to clear the wall next to the hole. I now have a 4-40 tap about a foot long. At least until i need that piece of rod more than i need a foot long tap.

Actually Steve, that is exactly what I would have done ! Only one thing different, I would have tinned and then filled the hole with solder and pressed the tap home into it whilst molten. It won't come loose after that.
 
Thanks for the video !

It does sound a little splashy, almost as if its missing a spark occasionally, or a valve sticking.

Anyway it looks very good and much much better than anything I could achieve. 👍
 
CFLBob !
I'm sure you'll figure out how smooth it out and keep it running.
You seem to trust me to be able to solve the problem too much 😜
Thanks .

BaronJ !
It does sound a little splashy, almost as if its missing a spark occasionally, or a valve sticking.
You are correct, a spark is sometimes lost
I'm checking the spark, the time and something,,,,,
Thanks .
 
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