MarkD

Hi,

How much run out is normal on the driveshaft of gasser engines. I need to check the runout on a FPE ( First Place Engine) that was in crash at our field.

Here is the test setup.

Thanks,





MarkD

w8ye

My Feedback: (16)

.0015"

excaliber

Years ago when the gassers first came out they were and some still are industrial off shoots.
The standards then was .003-.005,
Today a new crank between centers should be (my opinion) .0002-.0005 TIR. thats 10ths of a thousandth. I have seen a TIR of "0"

Antique

My Feedback: (4)

If you use the centers to test runout the shaft could conceivably be bent from the web out and still be made to show no runout in the center...It takes different measurements to test a crank...bore a hole in a 1/2 inch steel block just large enough to be able to put the shaft in and rotate it with a dial indicator on the end of the taper..straight there ? put the other end in and repeat..Straight there ? Put the indicator on the end sticking out of the free end of the crank next to the web..a twist will show up there, it needs to be straightened..finally put the crank in the case and check the end of the front at the taper..If there is still runout you can squeeze the webs together or use a tapered piece of steel to force the webs apart...It IS possible to get no runout at the end of the taper if all the other conditions are met...I try for less than .0005 with the crank in the case, measured at the very outward end of the taper..THEN you can bolt the case onto the mill table with the crank sticking up and put the flywheel on the crank, tightened up with a nut..Run the indicator over the largest part of the flywheel that is contacted by the hub...If no up and down runout there the crank and flywheel are REALLY straight...If the crank is straight and up and down runout is detected you can put a carbide end mill in the collet and carefully rotate the flywheel to mill the surface under the hub exactly 90 degrees to the shaft...No runout here means no runout at the tips of the prop...
I hardly thing any prop is perfect enough from the hub to the tips to have NO runout at the tip of the blade 10 or more inches from the hub....[8D]