[ksallred]

I've had my Series III machine for about a month, and today I noticed a "ticking" noise in the Spindle as if something is just knicking the spindle while it's rotating. I removed the PDB, removed the belt and ran the motor only at about 1000 RPMs with no issues. Then reconnected the belt, removed the drawbar and ran just the spindle and there is a noticeable "tick" between 800 and 1000 RPMs. So the noise is definitely coming from the spindle as all other hardware was removed. Any idea what might be making this ticking noise? I would think bearings would just create a high pitched squeal.

I have also had an issue with larger BN mills causing a lot of shaking in the machine. This is what led me to start looking at the spindle to see if there was a problem there. I have a 2F 5/8" HSS BN that I run at 2000RPM and 24 IPM .05"DOC. Makes nice cuts but sounds like the whole machine is shaking apart. I will probably slow this down even though I would think the machine should be able to handle it. There are several other things like drilled hole diameter that are making me take a closer look at the spindle. I even tried another drawbar thinking it might be bent for some reason, but no change.

[ksallred]

After more troubleshooting, it appears there is some wobble in the motor belt pulley. Running the motor by itself didn't show this (to the naked eye). But with the belt connected and tightened, the "tick" which comes from some wobble in the motor pulley/motor shaft returns. If I loosen the belt, the tick goes away. Problem solved.....except for knowing how much to tighten the belt? If I leave it too loose won't the belt slip in higher torque scenarios causing variations in spindle speed? Too tight wobble, too loose belt slip. Guess I'll just have to play with it to figure out the best tension.

[nitewatchman]

You may want to check the fit between the pulley bore and motor shaft.

nitewatchman

[ksallred]

There is a washer on the end of the motor shaft that was not centered when tightened giving the appearance of wobble, but everything else is fine. The ACTUAL problem was the PDB Spindle Flange. It had worked loose slightly giving the effect of an unbalanced tool. Flange tightened, belt tightened, no more ticking. Runs smooth again. Whew! I always think spindle bearing first. Never the simple things.