Splined Shaft On an Excavator

Any machine shops in the area?

Maybe one of these. http://www.mascus.com/yanmar/IE/SearchLocator.html

Have you ever heard of a Dutch Pin? It's a poor man's keyway, drilled into the space between a shaft and the hole it fits. Then pins are driven in to replace the missing splines. Depending upon the shape of the shaft, you may have to drill the holes from the blind side.

I'll go one better

drill & tap maybe 25-30mm [diameter] bolts or setscrews into the splines

you may have to take the slew motor apart & reassemble it after installing the bolts

if it's cast iron or steel use coarse threads & loktite them in

Machine in a very beefy keyway, and get yourself some extra keys.

I'm sure a local machine shop could make a replacement for You at a reasonable price.

oilcan13

Splined shaft is supposed be more torque handling arrangement than keys and pins. So if splines do not stand neither the keys or pins.

Your primary problem/root cause is, "why in the first place so much torque is existing at the shaft end?"

That's a good idea! Might take a little modification, but in the end, maybe better than the original. GA

how many splines?

what is the major & minor diameters [splines]?

length of splines, overall length

try to do a search Like this maybe

me either :D

there is some vendor of barstock out there with what you need on the shelf, it's just a matter of finding them

I'm no expert, I'm just trying to get you to give the most complete description possible of the part...

what does the rest of the shaft look like?

Hello Miik,

I am having a little difficulty with "The splined shaft in the slewing motor has lost its internal splines." Is this the output shaft of the slew motor which engages the slew gear?

I would be concerned about why the internal splines were 'lost' and the contamination of the hydraulic system.These answers may preclude the repairing of the slew motor.

Have you checked @ www.Heavyequipmentforums.com ?

Otherwise someone @ www.practicalmachinist.com might help you locate someone near to you that could make a replacement part.

Hope this helps.

Jay.

For a start - I know next to nothing about these small machines - but in larger ones a damaged slew assembly speaks of an accident, like dropping the bucket at high speed, or an operator who uses it for bashing things sideways.

If the splines are "worn off" then this speaks of slack in the mast pivots adding shocks.

I think the choices are fork out the euro against what the machine has earned to date (and re-bush out all the mast slack, maybe replace the slew ring and pinion), OR sell the machine for spares, OR trade it as 'in need of repair' for a new one.

I.e. I would not be making it "stronger" or "non-standard", as in general these systems are a balanced set of strength and life interrelationships well worked out. Hence they will not sell the shaft without the rest of the motor assembly.