Assembling the crank, crankshaft, encounter difficulties

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sysfocus

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I am not a professional mechanical processing worker. Parts are not made by me
I have processed most of the parts and tried to assemble and have problems.
The parts of the red arrow are active. Is this normal?
How to install the green arrow? How to assemble angle accurately?

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Can you use the split line in the counterweight as a consistent datum? The AA and BB are perpendicular to horizontal reference, so like a 90-deg square reference. Then CC and DD could be aligned using 30-60-90 triangle jigs. They may have to be notched out to compensate.

Maybe another idea is to work out the dimensions of a jig so the crank pins 'drop' onto a horizontal datum since the center shaft will always be in a fixed position.

I think this is an Ohrndorf V12?
 

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Can you use the split line in the counterweight as a consistent datum? The AA and BB are perpendicular to horizontal reference, so like a 90-deg square reference. Then CC and DD could be aligned using 30-60-90 triangle jigs. They may have to be notched out to compensate.

Maybe another idea is to work out the dimensions of a jig so the crank pins 'drop' onto a horizontal datum since the center shaft will always be in a fixed position.

I think this is an Ohrndorf V12?


Yes, he is an Ohrndorf V12,The drawings contain instructions, but English is not my native language, I can't understand the instructions inside. thank you very much for your reply, I will try it.
 
Did you do the machining of parts yourself & now doing assembly?
I am building the Ohrndorf 5-cyl radial. Yes some of the instructions are maybe not so obvious. he will reply by email (occasionally). English is not his first language.
I have the V12 plans, Its on my 'dream list'. I hope to see more of your engine.
 
Assembling that crankshaft has more issues than the angles. Getting the center shaft aligned is likely going to require an assembly jig. In any case, I'd try assembling the two ABCD separately and then joining them together.
 
The simple way to align the main shaft is to use a single rod of the correct overall length. Assemble and fix all the parts on it and then cut away the shaft where the throws (eccentrics) are located. This ensures a straight main shaft. You can make some simple cradles (a stand with a U shape on the top into which the rod throw will just fit) and of the right height to position the rod throws (eccentrics) at the right height relative to the main shaft. Because they are the correct height, they will only fit on the throws at the proper distance from the main shaft. You can figure out the correct cradle heights by thinking of all of the crankshaft shafts, main and rod as a bolt hole circle as seen from one end of the crankshaft. So if you go to a bolt hole circle calculator such as the one at littlemachineshop.com, you can have it calculate the cradle heights for you.
I hope this gives you the idea. If not, I can probably draw the idea out for you and post it.
 

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