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I have a wheel (1/2 inch diameter) and a metal rod (1/2 inch diameter) [axle]. Currently, the wheel on the axle results in the wheel free-spinning. How could I attach the wheel to the axle?

(The wheel is mainly plastic)

  • So you want the axle to drive the wheel rather than it being free-spinning? You want the axle and wheel locked together? How much torque does it need to handle? – JPhi1618 Oct 23 '19 at 20:47
  • @JPhi1618 Yes. I plan on powering it with a PMDC motor. – Jake Freeman Oct 23 '19 at 20:49
  • There are several ways of doing this, but the main idea is to clamp something to the axle and then attach the wheel to that thing. And pics of the wheel? – JPhi1618 Oct 23 '19 at 20:58
  • @JPhi1618 I am unsure of how to attach the clamped item to the wheel. – Jake Freeman Oct 23 '19 at 21:12
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In general to transfer torque through an axle to a larger round thing there are three main ways:

Light loads. (fractional horsepower) A flat space is ground on the axle. A set screw in the hub of the round thing (usually a pulley) keeps the round thing from spinning. I've run into this a lot on trailer furnace blowers.

Medium loads: (1 to small number of HP) A keyway is cut into the end of the drive shaft and in the hub of the round thing. Typically about 3/16 wide by half that deep. The two are lined up, and a chunk of key stock slid in. A set screw keeps the key stock from leaving. Table saws, stationary power equipment are good examples.

High loads: (Tens of HP) You have a hub with bolt holes. The round thing is bolted to the hub. (Car wheels are a good example)

As is mentioned in the comments: This is not a good choice for a driven wheel. It's designed to have 60 pounds on a line through the centre of the axel. If you drive it, there are twisting forces on the ribs. I don't think you'd have to drive it hard for the wheel to collapse on the first bump.

You may find it educational to look at self propelled lawnmowers and see how they are set up.

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You may notice that the wheel is described as being suitable for carts, hand trucks, etc. and is not designed as a drive wheel. If your loads are not excessive, you may get away with powering the wheel.

One method is to cut a slot in the flange of the wheel at the axle. Your drive axle would then have to be powered by the motor and the portion of the axle that engages the wheel would have a hole drilled and a pin used to engage the wheel.

Another method would be to create a mounting for a pulley or gear. A pulley will be easier for alignment purposes. Drill a series of holes in the wheel (think numbers on a clock) and add spacers and bolts to match the pulley. Drive the pulley with another one mounted to the motor. This method would not require the axle to be rotating.

Along this same line of thought, one can use a bicycle sprocket mounted in a similar manner to the pulley and replace the belt with a bicycle chain.

Gears are not as easily installed as alignment is critical, while chains and belts are more forgiving when using the TLAR method (That Looks About Right) for attaching the mechanisms.

Belts and chains also provide for gearing adjustment. Perhaps you need more power and less speed. Use a small gear/pulley on the motor and a larger one on the wheel. For the reverse, more speed, make the wheel pulley smaller and/or the motor pulley larger. A small change in either will make a substantial difference.

  • It should be noted however that a wheel like the one shown, with an all plastic hub, is not really designed to be a "drive wheel", in that when you use it that way, ALL of the mechanical stress is on that plastic hub. If the load is very light that's not probably and issue, but if it is heavy and your motor will exert a lot of torque, that hub may not last long. – JRaef Oct 24 '19 at 0:00
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    sometimes the best way to learn something is to break something! I do it frequently! – fred_dot_u Oct 24 '19 at 0:34
  • Couldn't agree more. Whenever someone asks me how I learned all of the stuff I know, I respond "One mistake at a time, hopefully none of them more than twice." – JRaef Oct 24 '19 at 0:42

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