belt sander belt tightness

How do I know how tight a belt sander belt should be? Should it err on the side of tight or loose? I know that too loose and it will come off, but mine seems to wander less if it is sort of tight.When its tight (like tight enough to "twang"), it cuts sharper too.. Just wondering what you guys do. I'm using a circa '75 Rockwell btw.
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Subw00er wrote:

Reach in between the belt (below the platen and give it a little downward push. It should deflect by about 1/2" at the most. Also, you'll want it to be tighter towards the inside (towards the casting) by a wee bit but this is a function of the tracking mechanism.

The Rockwell Internationals I've had the pleasure of knowing weren't good trackers. Try running a strip of tape around the idler drum to give it a crown.
UA100
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Crown helps align the belt, does it?
LMAO

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George wrote:

No. It helps with tracking.
UA100
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Ua100, do you mean it should deflect less than 1/2" in between the rollers?
It does seem to wander a bit when I first turn it on but then it stays where I set it. This is why I was thinking maybe I was setting the belt tension wrong.I think perhaps mine is set tighter than 1/2" deflection.
ps- thanks for the recommendation on the pulley (Browning), its great and definitely worth the extra $7.

the
mine
do.
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Subw00er wrote:

I meant that when you reach in between the underside of the platen and the belt, you should be able to push down the back side of the belt a 1/2" or so with moderate pressure.

Always bump start when you load a new belt. After it looks as though all is well back off (loosen) the faucet knob to unlock the tracking adjustment. You should be able to turn the tracking adjustment (the large flat thumb screw) and give it a slight turn. You should be able to track the belt in and out without danger of cutting into the machine if you don't get too carried away.
Play with it for a while. After seven years of daily using the machine for 3-4 hours at a stretch you'll be able to set the belt tension and track it without even turning it on. Don't Ask Me How I Know This.

Not a prob.
UA100
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By the way Subw00er, did I read that you'd had your machine taken apart all the way up and down? If yes, what did you run into when you got into the machine drive shaft? Reason I'm asking is, my '48 6" X 48" is squealing a bit and I really should attend to it. Trouble with that is, in for a penny, in for a pound so it'll mean a full bore restoration.
sigh...
Anyways (notaword tm Racine Tony), anything else that you found difficult/strange?
UA100
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I didnt take apart the shaft - just reoiled what I could. The only funny thing I came across was the double nut holding on the top roller - if I tightened it too much (which was barely holding it on) it would compress the bearing and add friction. I had to find the right spot for the first nut, then clamp it in place by securing the second nut.

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