Crankshaft Counterbalance Weight

[BRENT in 10-uh-C]

Originally Posted by SAJ

Would this one be rigid enough? It is a 42 inch throw facing and boring lathe weighing 10.5 tons without the face plate shown. There is no tail stock on this type but another face plate or a precision steady can be mounted on the rear.
My son and I are just fettling and setting it up in our collection.
I am just joking because I have no intention of machining a crankshaft in it.
I have trued up several Model A rear flanges in another of our lathes, after straightening the cranks in a press.
A crank grinder is something missing in our collection of machine tools.

Let's see a picture of your Tool Post Grinder for that thing!!

[Pete]

Originally Posted by daren007

What kind of lathe would you need to “Turn” crankshaft journals. How accurate finish can be obtained. Does anyone have more info and pictures?

For the Chev 4 cylinder midget engine we used an 18 inch Sebastian lathe. It was WW2 surplus that came off of a battleship. (Indiana)
We roughed the SAE6150 billet in the lathe. Left about .050 to finish in the crank grinder. After finish grinding to size we had the journals nitrided. While it could be done, it would take many hours to finish the journals to size in a lathe due to the slow rpm needed bacause of the billet weight and off balance situation.
The engine was very successful for 2 race programs and then the block broke through one of the main webs due to lack of support from the cylinder bank we cut off. The engine had a half of a V8 Hilborn injector, a Racer Brown ST2 grind on the cam and a Corvette head. The engine was in a 1947 Kurtis midget chassis.

[SAJ]

Brett, we did not get a tool post grinder with this behemoth. But there was one listed in the pre-war catalogue.
The machine has been "rescued" from the scrap heap so may never be used properly, but we may refacea flywheel etc just for fun. The 4 jaw chuck is too heavy for our 1/2 ton jib crane shown lifting the motor.
SAJ in NZ

[BRENT in 10-uh-C]

Originally Posted by SAJ

Brett, we did not get a tool post grinder with this behemoth. But there was one listed in the pre-war catalogue.
The machine has been "rescued" from the scrap heap so may never be used properly, but we may refacea flywheel etc just for fun. The 4 jaw chuck is too heavy for our 1/2 ton jib crane shown lifting the motor.
SAJ in NZ

It definitely is a monster, no doubt. I would love to have a big Monarch or ?? lathe like that however I just don't have the real estate to spare just to say I have one.

[Bob Bidonde]

Counterweights, when properly positioned and sized, will reduce reciprocating and rotating vibrations to less annoying frequencies and severity (amplitude). Lightening the flywheel / pressure plate promotes vibration about the rear engine mounts, and may manifest itself in clutch chatter. The flywheel and pressure plate are a gyro with a 82 pound rotor, and they oppose changes in motion of the engine as a whole, and the crankshaft.

[Pete]

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I heard a rumor on a street corner once to the extent that, the degree of balance in any rotating object is inversely proportional to the rigidity of it's mountings.

[Synchro909]

In reference to the comments about big lathes, my father worked in engineering all his life and on some big stuff. I saw a picture once (I don't know what became of that picture) of one of the lathes his company used. It was so big that the saddle had ladders for a man to access the cross slide and another to the top slide. The top slide had a hand rail around it to prevent the operator falling the considerable distance to the floor. I guess they had to use a crane to change the cutting tool and power to move the slides.
What they used something like that for, I don't know but I'd love to see it now. I guess it ended up making about 1,000 Toyotas!

[Pete]

Originally Posted by Synchro909

In reference to the comments about big lathes, my father worked in engineering all his life and on some big stuff. I saw a picture once (I don't know what became of that picture) of one of the lathes his company used. It was so big that the saddle had ladders for a man to access the cross slide and another to the top slide. The top slide had a hand rail around it to prevent the operator falling the considerable distance to the floor. I guess they had to use a crane to change the cutting tool and power to move the slides.
What they used something like that for, I don't know but I'd love to see it now. I guess it ended up making about 1,000 Toyotas!

Something like this? This one is kind of rusty. For one thing, they used them to make propeller shafts for large ships many moons ago.
A steel Co. in this area had one similar back in the 50's.

[Pete]

Here is a lathe I ran at a tourist railroad for awhile. They had an even bigger one they used to turn drive wheels off of steam engines.

[SAJ]

Wow folks! I will never say "mines bigger than yours" again.
I will stick to challenging 90 year olds to arm wrestling in future.
SAJ in NZ

[GPierce]

Cass Scenic Railroad, Cass West Virginia, 2019.

[Pete]

Originally Posted by GPierce

Cass Scenic Railroad, Cass West Virginia, 2019.

Neat stuff...That is about the same size as the one here but this one does not have a driven tailstock.

[Synchro909]

Originally Posted by Pete

Something like this? This one is kind of rusty. For one thing, they used them to make propeller shafts for large ships many moons ago.
A steel Co. in this area had one similar back in the 50's.

Turning propeller shafts makes sense. Come to think of it, I do recall dad talking of doing that and cutting gears for such like heavy applications. He served his apprenticeship during the war cutting gears for the military. Probably have to buy them from China these days and who looks like the most likely adversary???? What could go wrong, I wonder.