Ideas towards Cub-centric wheel improvement...
Posted: Wed Oct 07, 2015 2:13 pm
Hey Derbians,
So I'd like to do some more "thinking out loud" here, and I'm relying on you guys (and gals?) to come poke holes in the flaws of my reasoning, as you see fit.
So here's the problem I want to solve: There's no good way for cubs to true up their wheels that can be done without expensive equipment. There exists the Derbyworx wheel shaver, but I've actually become less pleased with this tool, the more I've worked with it and evaluated the output.
Here are my issues with the Pro Wheel Shaver:
- The pin is rather loose in the bore of the wheel, leading to slop and potential uneven pressure on bore.
- It requires a LOT of time and patience to get a good result
- The blade is finicky and snags easily.
- Turning the wheel by hand sucks.
What I'm looking for is a solution that is:
- Straightforward: A cub should be able to use this without too much trouble
- Affordable: This is debatable, but I'm thinking 100 bucks or less -- far less than even a cheap metal lathe
- Effective: Should be able to true the outside of a wheel to within .001" runout, parallel to the bore.
Ideas sort of rattled around in my brain for a while, but then I saw these plans for a homemade metal lathe. Based on the parts used, I think that I might have an idea of how I'd tackle the problem. Of particular interest to me were the support blocks and the bearings.
So, here's the basic plan: We need a way to mount a wheel on a turning mandrel that allows for some way to either sand or trim it with a tool. The wheel needs to turn with low runout and, ideally, the method should NOT put friction on the inside of the bore as a result of the truing process.
So the meat and potatoes of this design would be a turned cylinder with a main diameter that would fit into a standard sized bearing, and a protruding "pin" that would snugly fit a BSA wheel with an interference (friction) fit for working. The other end of the cylinder would have a pulley guide affixed for connection to some kind of power source for turning (possibly a drill, or dremel, or dedicated motor). The cylinder would be supported by two bearings, which would sit within two support blocks, similar to those shown in the aforementioned lathe plans.
Here is a very bad sketch of what I'm thinking of:
Because the fit would be a press-fit, it would require that the bores be reamed to a uniform size before working. I believe the investigation done by Stan Pope would be helpful in this regard. I've listed 0.098 because that's what Stan was using, but possibly a smaller size would be appropriate? Regardless, a reaming tool would be required to make accurate use of the wheel-turner-thingie.
At this point, I've omitted any sort of tool holder or fitting. There are a few options that could be used. For example, a machining block wrapped in varying grades of sandpaper might be sufficient. Or an actual cutting tool might be preferable. The former is more in line with the 'light sanding' guidelines that a lot of Districts use, but the latter is possibly more efficient?
Anyhow, as before, just thinking out loud here. The ultimate goal would be to put more accessible tools into the hands of Scouts that could effectively yield quality parts without the need to resort to expensive equipment, or external services. All thoughts welcome.
So I'd like to do some more "thinking out loud" here, and I'm relying on you guys (and gals?) to come poke holes in the flaws of my reasoning, as you see fit.
So here's the problem I want to solve: There's no good way for cubs to true up their wheels that can be done without expensive equipment. There exists the Derbyworx wheel shaver, but I've actually become less pleased with this tool, the more I've worked with it and evaluated the output.
Here are my issues with the Pro Wheel Shaver:
- The pin is rather loose in the bore of the wheel, leading to slop and potential uneven pressure on bore.
- It requires a LOT of time and patience to get a good result
- The blade is finicky and snags easily.
- Turning the wheel by hand sucks.
What I'm looking for is a solution that is:
- Straightforward: A cub should be able to use this without too much trouble
- Affordable: This is debatable, but I'm thinking 100 bucks or less -- far less than even a cheap metal lathe
- Effective: Should be able to true the outside of a wheel to within .001" runout, parallel to the bore.
Ideas sort of rattled around in my brain for a while, but then I saw these plans for a homemade metal lathe. Based on the parts used, I think that I might have an idea of how I'd tackle the problem. Of particular interest to me were the support blocks and the bearings.
So, here's the basic plan: We need a way to mount a wheel on a turning mandrel that allows for some way to either sand or trim it with a tool. The wheel needs to turn with low runout and, ideally, the method should NOT put friction on the inside of the bore as a result of the truing process.
So the meat and potatoes of this design would be a turned cylinder with a main diameter that would fit into a standard sized bearing, and a protruding "pin" that would snugly fit a BSA wheel with an interference (friction) fit for working. The other end of the cylinder would have a pulley guide affixed for connection to some kind of power source for turning (possibly a drill, or dremel, or dedicated motor). The cylinder would be supported by two bearings, which would sit within two support blocks, similar to those shown in the aforementioned lathe plans.
Here is a very bad sketch of what I'm thinking of:
Because the fit would be a press-fit, it would require that the bores be reamed to a uniform size before working. I believe the investigation done by Stan Pope would be helpful in this regard. I've listed 0.098 because that's what Stan was using, but possibly a smaller size would be appropriate? Regardless, a reaming tool would be required to make accurate use of the wheel-turner-thingie.
At this point, I've omitted any sort of tool holder or fitting. There are a few options that could be used. For example, a machining block wrapped in varying grades of sandpaper might be sufficient. Or an actual cutting tool might be preferable. The former is more in line with the 'light sanding' guidelines that a lot of Districts use, but the latter is possibly more efficient?
Anyhow, as before, just thinking out loud here. The ultimate goal would be to put more accessible tools into the hands of Scouts that could effectively yield quality parts without the need to resort to expensive equipment, or external services. All thoughts welcome.