Drive pullies

[smittys800]

Hey Gang,
Anybody replace the drive gears on the Spindle and the Spindle motor. Mine are worn pretty good, to the point of ear plugs and Muffs!!
Thanks,
Smitty

[carbidecraters]

Are you sure its not your motor mounts? A quick way to tell is to loosen the tension on your motor...its the large two nuts on the side with the cable in the middle. I dont see how these pullies ever go bad! We had the same issue is was a crackling noise that was extremely loud...I was waiting for bearings to come shooting out of the spindle and it turned out to be the motor mounts saggin in the back making the belts crackle on the spindle pulley. You can also try a little wd 40 and spray the belts to see if the noise goes away...if it does then its motor mounts. All this refers to the POZI system that uses 2 belts not the 6 belt system.

[DareBee]

KMAC has solid, aftermarket mounts, which I was very happy to use when I replaced the stock rubber units.

[smittys800]

I have the VMC 15 7500 RPM. Looking at the parts break down, the 7500 RPM setup has a different mount for the Spindle motor.
As for the gears, mine have a definite EDGE, installing a new belt only made it worse.

[carbidecraters]

Then look at your motor mounts...the spindle motor mounts on either side. If you pull the cover off the front and stand on the table you can see down into the casting where the motor mounts are located. Motor mounts that Fadal used were rubber sandwiched and that rubber got flat over the years (Wasnt thought out that well). This will give you that crackling noise.

[Edster]

I've got a 94 vmc 15 that I replaced the v groove pullys with the cogged version. Sorry I don't know the technical names The old pullys are still good if you need them let me know. I replaced them because the belt would occasionally slip I had to heat the pully to remove it with a puller. and when reinstalling them I heated them on a hot plate so they slipped on. There is a technical buliten on heating the pullys. Apparently people were getting them too hot on the machine and the heat transfered into the spindle causing a spindle failure. My machine also never had any rubber motor mounts. They were aluminum for the old pullys, and the new pullys needed new spacers which were also aluminum.

good luck

[smittys800]

Thanks for the advice,
Going to pull the Cover off.... Again and have a look see at the Mounts.
Smitty

[smittys800]

Ok,
NO motor mounts on my VMC 15, 7500 RPM. The Spindle is mounted to some Boss's in the head stock.
So, with the belt riding in the middle of the pullies, noise is much less, but the belt will ride to the top, or the bottom, depending on where it is on the pullies.
Any idea as to how to get the belt to track in the middle, what about tension of the belt itself. I have about 1/4- 3/8" of PUSH on the belt.
Here are some pics,
Smitty

[smittys800]

So I messed around with the belt tension, and got to a point where there is some slack, but the noise is MUCH less than when I had some good tension on it. Seems that the pullies really need to be replaced, that will be one Summer job I am not looking forward to!
Smitty

[Edster]

What year is the machine? When I updated ours to the new belt system like you have, one of the spacers for the plate the motor mounts on was adjustable. It has threads and a large nut. The motor mount plate is flexed by this spacer and that is what adjusts the belt tracking. I never had any luck adjusting mine. Btw our belt is noizy too, so is our sl-10 and our tl-1 all of wich have the cogged belt. It might just be the nature of the beast.

[smittys800]

Machine is a '95 VMC 15, Road Hard and left to dye HAHA
Came to the right place for serious TLC. After the Z axis fiasco, seems to be running just fine, other than being rather loud!
Spoke with Kmac, you are correct, a little heat and a good puller will get them off. The Spindle gear is the important one to maintain T/C alignment, I guess there are alignment marks to aid in that.
This will be a Summer project,
Smitty