How can I stop my lift axle from bending?

I'm trying to put a lift on my bandsaw mill and I'm having a few problems.

The lift is used to raise and lower my saw head, and is powered by a gear motor. My 1" axle if bowing toward the motor when under load of approx 300 pounds on each side. I know I don't have enough support on the axle and was going to add bearings on the outside ends of the shaft and one on the side of the main chain sprocket.

Here is a photo, sorry about the dark it was a bit late.

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Do you guys think placing flange bearings on the ends of the axle and one next to the large sprocket would fix my bending problem?

Thanks

Reply to
Modat22
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What you have to do is: Move the two existing bearings to the outside (as near as possible to the outside sprockets) and add one bearing as near as possible to the big sprocket. It is best to not use plain vanilla ball bearings, but ones that can stand angular misalignment (don't know how you call them). But they are more expensive and can't stand that much side load.

Nick

Reply to
Nick Müller

Yes, the shaft is insufficiently supported. No, simply adding bearings on the ends of the shaft won't do any good. The problem is that there is too much distance between the bearings. Ideally, you want the ouside sprockets and the large sprocket mounted between the bearings and all the components as close together as they can be without actually interfering with each other. Of course, your installation may not permit that, so what to do?

some suggestions:

  1. Mount each sprocket between a pair of bearings and join the (now) three shafts with flexible couplings or u-joints.
  2. Mount everything on a much larger shaft (say 3")
  3. Move the large sprocket as close to the bearing as possible and remount the motor to accomodate it.

In general you want the tension load (in the chains) to be as close to a bearing as possible, and between a pair of bearing if possible (never outside a bearing pair if you can help it.). If you simply add another bearing or two right next to the big sprocket, this might work, but you will probably need self aligning bearings there and be prepared to shim them to align with the shaft. The misalignment loads will tend to shorten the bearing life if not properly installed. Hope this helps

Reply to
Kelly Jones

The easiest method at this point will probably be adding putting the all the sprockets between bearings, the large sprocket is a surplus weld on type and unfortunately its already welded on the shaft.

Thanks for the input, I'd hate to have to change out the axle to a larger version but if all else fails that's next on the list.

Sam

Reply to
Modat22

Since the shaft is powered by a gearmotor at a slow speed and low duty cycle (assumptions), there would be little need for concern of destroying/smoking the bearings any time soon, even if they're not perfectly aligned, IMO.

If it was my own equipment for my own use (not in a workplace), I'd probably add 3 or 4 bearings.. 1 or 2 (1 near, or on each side) for the big sprocket, and 1 on each end.

The upper member appears to be welded sections, and you might consider reinforcing it as you'll be expecting it to share the load, away from the vertical columns.

each side the axle and was going to add bearings on the outside ends of the

Reply to
Wild Bill

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