Chuck Balancer

Just for fun

Tim Young
H-M Lifetime Diamond Member
Joined
Oct 7, 2020
Messages
2,090
Made a unit to check the balance of my 4-jaw chuck. I bought a bicycle exerciser unit at a secondhand store for $5 bucks a while back. I disassembled it and turned a couple of bearing holders and a shaft to go between them. It seems to work, the best I can tell it's a little over a half ounce out of balance. I have included a couple YouTubes of the chuck on the balancer. I sure need to work on the YouTube thing. I just transferred videos from my phone, they sure are large.

The initial test.

With some makeshift weights.

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So you centered the rod with the chuck on the lathe? I’ve tried doing the same thing with one of my four jaw chucks but I wasn’t confident on if it was dead centered. Which would compound the imbalance No? I have a grinding wheel balancer.
 
Yes, I centered the rod while the chuck was mounted. I agree if the rod is off center that the ballance would be off. I guess to verify I could put the chuck back on the lathe, remove and replace the rod, center it again and see if the ballance shows up at the same location and the same amount weight needed.
 
So, I took everything apart and put the chuck back on the lathe. I wanted to put an indicator on the outside of the chuck to check concentrisity. It's almost round, except for about a 3" section where it's got a one thousands bump.

I centered up my little bar again and put it back on the ballancer. My light mark showed up again about 1 inch away from my first test. This time I put a dial indicator on the outside it's off about three thousands.

I'm going to go ahead on install a half ounce weight at the light location and give it a test run.
 
Success!

I finely got back in the shop to finish up on my balancing project.

I used my gun powder scale and came up with 205 grains, .46857 oz. I cut up a little chunk of aluminum and attached them with double side tape.

Before the ballancing at 575 rpm or a little lower it would start to shake the light, at around 700 rpm you could feel it in the whole machine. It would get a little worse up to about 750 rpm and then start to smooth out a little but I could still feel it.

After the balancing I ran it up 1000 rpm with no sign of a shake.
 
Mine starts to shake from 500 to 575 then it goes away. I e changed chucks and is worse with the 4jaw that came with the lathe. Which is okay but the backside inner casting is pretty rough. It does need to get balanced.
I think my problem is the drive pulley for the lathe. It has the brake mechanism in the back and I think it’s out of balance. Transmitting it through the lathe at the specific rpm’s. I deal with it for now and don’t use any rpm at 500-600.
 
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