Nomad 883 Belt adjustment needed

After several hours on my Nomad 883 Pro, I experienced a problem this evening that needs addressing. After 3 successful completions of a drilled block of wood that I plan to use for storing my bits, I was about 1 hr into making my 4th block when I heard a loud ratcheting noise. I waited and watch until I heard it again and I saw that it matched the spindle slowing way down and then stopped and back to 6000 rpm again. The exact cut it was making was a grid of 40 - 1/8" holes x 1/2" deep. Depth of cut was less than .05" on each of a dozen or more passes and depth of hole was around 1/4" at the time. This occurred on several random holes on numerous rows right up until that particular pattern was finished. The next operation was a group of 12 - 1/4" holes cut with a radius of .126" for clearance. All of this was done with the 1/8" flat bottom 2 flute end mill #102. Cutting the 1/4" holes did not see a repeat of the problem seen on the first half of the job. When the job completed I examined the belt drive. It is extremely loose and can be depressed at least 1/4" between motor and spindle pulley. Any idea what might be going on?

Plunging too fast into hard material can cause the spindle to stall. What was your plunge rate? Also, 0.05" doc is deeper per cut than the doc’s in the feeds and speeds chart. Pine, for example, is 0.03". Perhaps you’re just going too deep too fast?

I don’t know on the belt though.

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The belt for driving the spindle shouldn’t be loose, it should be able to be depressed ~2–4mm so should be tightened up.

The 4 bolts holding the brushless motor allow the belt to be tensioned.
The belt does not have to be tight.
When pushing in the center of the pillows, about 2-4mm deflection is normal for the belt.


as long as you’re not seeing the belt slip you should be good to go. If the belt is too tight you lose a lot of torque to friction.

To test the motor, connect to the machine, bring up the MDI and:

…type M3S1000 and hit send. This will turn the spindle on at 1000RPM. Let it run for a bit and look for odd behavior (like stalling). Now type M3S10000 and hit send. This is max RPM. If the motor is at fault, the spindle will stall within a few seconds/minutes.

The deflection on the belt is in the order of around 10-12mm so I’ll adjust it accordingly. Also Mark your comment on my depth of cut is well taken. I guess I was thinking the rigid quality of the Nomad 883 Pro could easily handle a plunge cut of .05" in pine but I was hearing high pitched resistance on each peck it made so I will trust the feeds and speeds chart more.