Question on shimming electric motor

[LewisCobb]

Not sure if this is the right forum to post this question in, but I figured a bunch of machinists would probably know the answer so here goes

I've got a woodworking planer and it has a 3HP electric motor that feeds a 3 belt pulley system to the cutterhead. I am trying to get the pulley faces to be in the same plane and in line with each other. The one on the motor is slightly angled away from being in the same plane as the cutterhead pulley, but the adjustment for the motor really only allows the pulley to shift left/right, not tweak the angle of the face of it. It looks to me that the only way to do this would be to insert shims under one end of the motor's mounting plate.

My question - by shimming the motor mounting plate like this, the mounting plate will no longer be sitting "flush" on the bracket that it's attached to. Are there any issues with weakening the mounting mechanism as a result of this, or is this the normal thing that's done to currect such issues as this?

I have a call into the manufacturer but as usual I am doing these things at a time when they are not available to discuss the issue with me.

Thanks for any help people can provide.

Cheers,
Lewis

[Geof]

Originally Posted by LewisCobb ......My question - by shimming the motor mounting plate like this, the mounting plate will no longer be sitting "flush" on the bracket that it's attached to. Are there any issues with weakening the mounting mechanism as a result of this, or is this the normal thing that's done to currect such issues as this?.....Lewis

Being cautious about doing this is a good idea, but if both the motor plate and the bracket are steel it is probably okay. If one or both are aluminum castings, or if one is cast iron you have to be careful because there is a chance you can fracture these by doing the bolts up very tight when the two surface are supported at an angle with the shims; neither cast aluminum nor cast iron are very ductile, they tend to break not bend, steel bends.

If the belt tensioning mechanism use long setscrews to push the motor back so the tension in the belt is acting on these and not relying on the bolts creating enough friction to stop the motor moving you are probably okay no matter what the metals are; just don't get carried away tightening the bolts.

[LewisCobb]

Hi Geof - thanks for the feedback. I have taken a picture of the motor mounting so you can see the actual set-up. The bracket for the motor is steel I am sure, but the plate that it's mounted against looks like a cast item - it's pretty hefty looking. The tensioning mechanism is a screw that pulls on it not the motor plate.



Here's the picture -


Here's a shot of the side of the machine showing the pulley/belt system. There's 3 x 3/8" belts - I would think there's a fair bit of yanking force on that tension bolt in the previous picture.

[Geof]

I guess two pictures are worth two thousand words.

The bracket the motor bolts onto is pulled down by a tensioning bolt on one side.....the opposite side it must be pivoting on a shaft.

Have a look to see if this shaft has some method of adjust to do what you need, align the motor shaft so it is parallel to the planer shaft.

If it doesn't have adjustability I suggest trying to figure something out there, rather than shimming the motor.

[LewisCobb]

ok - but seeing behind that motor is virtually impossible until I can hike it up in the air on a shop crane - the thing weighs about 500 pounds. I took a look at the parts manual for the machine and it looks like the pivot shaft on the other side of the motor is similar as the one on the front in the pictures, but the bracket is molded like a door hinge and the pin is the shaft. Everything seems to be clamped into place with set screws and there's no real adjustment anywhere.

I'll try and get a look at it with a mirror or something tomorrow and let you know.

Thanks for your ideas and help !

Lewis