Tell me a little more about how you adjusted the tension. As you know with the 101.27440, the motor hangs off the back and its weight sets the tension to the inner belt. But the first-level belt (motor to pulleys) tension is set by that adjustable screw. I discovered changing that tension affects vibration and noise. But it's all eye-balling it. How did you find 'the happy spot'?
thx
-Mike
Continuous eyeballing and adjustment until I get tired of fooling with it.
I have had some experience setting tension on industrial motors. I don't know the deflection vs tension formula but I have a grasp of the general area of what is acceptable. When I first acquired the lathe and installed a new motor, I adjusted the belt tension to "TLAR", (That Looks About Right) and then tinkered with it until I got tired of fooling with it. Like many machinist jobs, there is a matter of touch that cannot be quantified, it just has to be learned through experience. I suppose my expression could just as well be "That Feels About Right" ot TFAR. Sort of knowing just as the torque wrench clicks.
Belt tension should
never be set using the motor weight, there is a formula that I can't remember. But after 50 odd years, I sort of have a feel for machinery. Sorry, I can't get closer than that. Most belted machinery has that setscrew available. Sometimes on used machinery, it will only be a tapped hole where the previous owner didn't know. Looking for instructions for automotive belts will get you in the ball park. It won't be exact, but quite close.
I have a couple other Atlas machines, a Shaper and a Milling Machine. They also have that screw on the motor bracket. The shaper didn't have a bolt from the previous owner. But I looked, and
there was the hole. . . It was acquired from a school so had many users tinkering with it. No telling how long it had been gone.
The lathe was later acquired from a welding shop who had found it from the original purchaser. Being mechanically inclined, they knew what the screw was for. I watched while he torch welded (OA) a carburator casting. I was quite impressed, they knew what they were doing. The milling machine was also acquired from a man that was mechanically inclined and knew not to remove the screw.
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