Turning a crankshaft

Fritz Maurer

Well-known Member
How does a machinist know the diameter of the next undersize? I'm taking a crank to a shop who probably does not have a listing for a W-12. I was planning on getting the bearings from Rice's, but I am hesitant to have them provide the dimensions to the machinist; if the crank turns out wrong, I'm stuck with it. I would rather the guy doing the job find out for himself. I have never heard of a crank being refused for lack of information, that's why I wondered if there was some other way of checking the diameter. Thanks, Fritz
 
I used to grind shafts. We had a book that had the forging numbers of cranks and the specs. Journal sizes and stroke . Also listed the undersizes of bearings available. A shop with a grinder will have the info too.
 
I have always either had the machinest supply me with bearings after doing the grinding or write down EXACTLY what I am to get. It seems like you are putting the cart before the horse.
 
The BEST machine shops will usually refuse to do machine work WITH OUT the new replacement parts in hand. Tolerances could be slightly off.The BEST guys are checking everything BEFORE turning them down.If not,you can end up with sloppy machine work,or even worse,a "junk" un useable crank shaft. If they ARE a GOOD shop,they should be able to produce any engine bearing made.If not,I would question their back ground in doing crank shafts myself.

BTW,My engine guy WILL NOT EVEN think about boring a block with out the new pistons,or any other major work with out the replacement parts sitting right there with him.
 
Let the machine shop take care of the bearings or just let them turn it so its ready for the new bearings if it has to turned over 30 thous get another crank. They will know what the specs are.
 
A W-12 has the same diameters as the A,B,C, cranks. The rod bearings are the exact same and the mains will work with a little grinding.
 

We sell tractor parts! We have the parts you need to repair your tractor - the right parts. Our low prices and years of research make us your best choice when you need parts. Shop Online Today.

Back
Top