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View Full Version : PM 2800B Belt Tensioning



johnny means
12-30-2021, 11:36 AM
I know a lot of guys on here have this machine. I also know that many of them have had to deal with maintaining it. So my question is, why aren't my belts tensioning. The pulleys will move up and down. They're just not doing it during adjustments. I am adjusting while it runs.

Mark Bolton
12-30-2021, 12:53 PM
I dont have that machine but have you tried some dry lube on the shaft? Those reeves style drives always seem to gum up on me overtime and if its left unattended the sheave halves can really take a beating. I have a small delta on a bench that was given to me with cheap cast halves that got sticky and pretty much self destructed. I have a 4" diameter piece of 6061 siting in the lathe to turn new sheave halves when I get time. P.S. sure you know, but that center segment and the top half under the spring need to slide freely on that shaft. If there is any sticky/galling there the top half can hang with the spring in the compressed position and you have no VS.

johnny means
12-30-2021, 8:04 PM
I dont have that machine but have you tried some dry lube on the shaft? Those reeves style drives always seem to gum up on me overtime and if its left unattended the sheave halves can really take a beating. I have a small delta on a bench that was given to me with cheap cast halves that got sticky and pretty much self destructed. I have a 4" diameter piece of 6061 siting in the lathe to turn new sheave halves when I get time. P.S. sure you know, but that center segment and the top half under the spring need to slide freely on that shaft. If there is any sticky/galling there the top half can hang with the spring in the compressed position and you have no VS.

Bingo. Thank you. It seemed to move fairly freely when I squeezed the pulleys with my hands. After closer inspection the lubrication was dried up like coagulated blood. Disassembled, cleaned, and oiled and the belts stay tighter than a frog's bottom. I'm betting that that issue has been the root of a string of mechanical issues with this thing.

Also, for anyone that comes across this in the future. This drive has a stationery middle pulley locked in with stacked set screws on each side