STILL beating up on this 750. Found the drivers side crank pin has been cut badly by the interior washer spinning because the nut was loose for who know HOW long. So, the Question is, I'd rather not have it welded up if I can find another crank cheek, any out here for sale? Thanks Ron Parola

At this point I would ask what has been found for consistancy in finnished dimentions of PRESSED parts,,,I recall discussions on this and as I recall,,,parts of that era are NOT always interchangable,,, I remember when I got a new timing gear from Cefreed, at Bugatti parts,,,it was .250 too wide on the hub,,I questioned it and was told that the engine was no doubt worn,,so there was extra dimention to allow it to be machined to a clearence of .004 ,, Oh yes it was the famous FIBER helical gear , w/ shaft below the flywheel at the rear,,,In case any of you get to work on one of these,,there are 2 starter teeth that are ground short, so it will come out ,,,I now have a vvverry small bald spot,, tear my hair out ,, haha,, I have seen funny crank parts and have wonderd if there was a mismatch of fits by unqualified mechanics,, Many years ago I was to assemble a motorcycle crank,,,,and ended up with 12 flywheels before I got a pair with the same stroke,,the owner was planing to assemble what he had,,never realizing the f/wheels stroke was .030 different,,this was a 1936 machine,,then the fun began,,,Can we share input on this,???,,,Ben

NOTE,,the axle ,,the shaft,,,is about .050 larger in the middle,,fitting the GEAR,, and is smaller where the crank and loose eccentrics fit,,,,SO DO NOT attempt to just push the shaft through,, Cheers Ben

I have found that the 1910 - 1914 10 hp crank throws take about 16 tons of press to remove and replace them from their shafts. The 20 hp throws take about 25 tons, and the 30 hp crank throws take about 35 tons to remove and replace. Proper fitting press plates, a good straight press, and proper preparation all make for a nice press job. Before reassembly, lightly chamfer all the sharp corners to prevent gauling of the shafts and if the fit is real tight, use a good antisieze lubricant. Often a little heat from a torch properly applied hedges the bet on a trouble free press job for both removing and replacing the crank throws. Everytime that a crank throw is pressed on and off, the press fit will become looser. If a shaft fits too loose for either a crank gear or a crank throw, make a new shaft that will give a good tight fit. Shafts are easy to make. One engine builder says that he always machines out the shaft on the 30 hp engines rather than pressing them out because of the chance of gauling. If installing modern main bearings on the crank throws, I anneal the old roller bearing sleeves before machining them down. I buy the biggest inside bore bearing that I can get into the bearing saddles. The reason why is that if a too small of bore in a bearing is used, the press fit of the crank throw is compromised by the lesser metal in the bearing sleeve and the crank throw will work loose more easily. 10 hp engines are real bad with this. Howard "Dewey" Johnson of Lemont, Illinois has a cure for this problem. He makes new 10 hp crank throws that do not use a sleeve on the crank throw to press the bearing over. His new crank throws come with the extra sleeve metal already as part of the crank throw. His 1910 - 1914 10 hp engine rebuild kits are wonderful. He addresses all of the 10 hp engine weak points. About 4 years ago he asked if there was enough demand for to make the 20 hp crank throws? I do not know if he ever made any of them. There is a lot more to doing all of this than what I have written here. If you are a novice at doing these operations, get some professional help to keep from messing up the hard to find Stanley parts. There is no substitute for experience.



Edited 4 time(s). Last edit at 03/08/2007 02:26PM by SSsssteamer.

Hi Pat,,,Could you convert the ton pressure on the cranks to thousanths of interfearence fit,,,One will not know the press on assy til the machining is done,I think,,and the tons will change if the things outside the crank sleeve are a differend dimention,,,,,On the bikes we used .003 per inch diam, well braced hole w/ 65 ton steel,,anything over .0035 to .004 just resized the hole,, All these early engines have a somewhat soft steel and DO tend to pickup on the press,,, so care is in order,,,cheers Ben

Dear Ben, I was also a press man for Skagit Corporation from 1965 to about 1969 in their transmission department. There are five different classes of fits in ordinary machinery. There is the running fit, the push fit, the driving fit, the forced fit, and the shrinkage fit. With the Stanley crank shaft, we are concerned with the forced fit. Forced fit is a term used where a larger diameter shaft is forced into a smaller diameter bore with the parts being at the same temperature. Materials of different hardness will have different press rates, than other metals with the same hardness. Like you said, the diameter of the hub is also a variable that directly affects the required pressure to force press the parts together. A longer length of bore will also add to the pressing pressure required as the parts continue to be engaged. For a 1" to 2" diameter shaft like the Stanley crank shaft, the minimum interference would be 0.003" and the maximum interference would be 0.004" for a proper fit. About 0.002" per bore diameter inch makes a good forced fit in most cases. Your figures are about spot on. The Stanley 30 hp crank throws goes on at about 20 tons for the first half of the press. In the last half of the press, the pressure climbs up to about 35 tons. Crankshaft bore diameters vary, so if you are mixing used Stanley crank throws, a custom shaft may have to be made to match the mismatched bore diameters. I would never accept a 20 hp crankshaft that would force press on under 10 tons, just not tight enough. Your force fit pressure guess will still be in the ball park, but you will not know exactly how much pressure it will take to force fit your parts until you are done pressing them together.



Edited 1 time(s). Last edit at 03/04/2007 06:47AM by SSsssteamer.

We have actually stalled a 50 ton press on a 20hp crank, you could see the crank flexing EEK!!! We heated up the throw and let it sit, in a few hours time it came loose with a mighty pop. But I digress, since nobody has a spare crank half how about a whole crank?? Thanks Ron Parola

Dear Ron, I usually do the same as you did with your crank throw, if the press stalls, heat the throw and it will usually pop loose. In removing your crank throw, if you would have heated up just your shaft instead of your throw, and then let it cool, the crank throw would have came off easier than it did. I do the same thing with stubborn steam chest covers and cylinder heads. Heat them up to where they have expanded from the heat and them let them cool. After they have cooled, the heads and cylinder covers will then have more clearance and they will usually screw right off. In pulling the master pin in my D4 crawler tracks, I always get the master pin cherry red and then let it cool. Then I heat the track link around the pin and the pins usually drive out quite easily. Ah, the magic of the hot wrench.