How tight is a gear stuck on a shaft?

Your question cannot be answered.

To calculate the forces needed one must know: The ID and OD of the tube. The OD of the gear. The strength of the Aluminum. The bearing area of the gear. All dimensions to .0001"

Gears are routinely keyed onto shafts, not pressed. Often held with Loctite, or set screws. If a press fit is used, the interference is typically .001' per inch of diameter of the shaft.

DJ

To calculate the forces needed one must know: The ID and OD of the tube. The OD of the gear. The strength of the Aluminum. The bearing area of the gear. All dimensions to .0001"

Gears are routinely keyed onto shafts, not pressed. Often held with Loctite, or set screws. If a press fit is used, the interference is typically .001' per inch of diameter of the shaft.

DJ

I don't have anything to add directly to the question. You could try to rig some support behind the gear and either press or drive the tubing on. A better method is to select or ream the tubing for a snug fit, make a few small cross holes, and use epoxy.

Don Young

Support the gear directly. Damage to the motor probably won't be visible until it's too late.

Maybe you could find a gear puller that fits. The cone on the puller screw will flare the tube unless you protect it with a socket or such. Bevel the end of the gear a little to make the tube center itself. The tube will almost certainly shift out of line so watch carefully and only press it on a little at a time, because once it shifts it will be very hard to correct.

Otherwise you could notch two steel plates to fit together around the shaft between the gear and the motor and rest the plates on a solid support, such as a short piece of car exhaust pipe. An arbor or hydraulic press is better than hammering.

This is a good application for a set of cheap black-oxide impact sockets. Chromed sockets don't take well to hammering.

If the OD of the tubing is a standard size, you could slot the tube and squeeze it into the teeth with a two-piece shaft collar.

Jim Wilkins

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How do you all ream a tube?

My low-tech way of doing that is to spin the tube fast as possible in a drill chuck and maybe move sandpaper or a drill bit (either stationary or spinning in the opposite direction of the tube) into the tube opening. But this tubing is 5/8" diameter, so it cannot be spun in a 1/2" drill chuck.

I don't usually ream tubes, I bore them to size in my lathe. You're very limited without machine tools. Once you have them you can make just about anything you can think of.

John Doe wrote in news:2K3Ik.3205$ZP4.2648 @nlpi067.nbdc.sbc.com:

It is routine in production to heat the tube and cool the gear for press fits. The gear would typically be immersed in liquid nitrogen, while the tube is induction heated just prior to assembly. This allows a much larger interference fit, while lowering assembly forces considerably.

If you dont need to take much off then you could get a bit of round bar, hacksaw a slot down the end to insert a strip of emery cloth wrap it around until it builds up to a reasonable fit for the hole and spin that in a hand drill. make sure you wrap the emery cloth the right way.

Taper the leading edge of the roll a little so it has a dull point like a drill bit. Countersink the end of the tube. Jam the roll into it to find the maximum possible diameter that will go in, and tear it off there. When it wears down you can slip some of the torn-off piece into the roll.

Can't speak to your application, but that's exactly how some automakers now put harmonic balancers on crankshafts (which also makes putting it *back* on when you've had to work on it interesting: bag of ice on the crankshaft, boiling harmonic balancer in a pan, run out to garage with hot harmonic balancer....). Yes, I've got two examples: the '95 Neon I used to own, and the '00 Intrepid R/T I still own. Yes, I do prefer keyed shafts by a wide, wide margin.