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Inventioneering on Basement Roads
May. 25th, 2021 01:56 pmSo I'm now working on the third iteration of a bicycle maintenance tool intended to immobilize the pedal crank arms while torqueing them in place on the bottom bracket spindle.
Because I don't have a helper, these days, I've had to make do with sandwiching the crank arm and chain stays between two pieces of scrap wood and securing this awkward assembly with c-clamps. And the only answer to my Google query, in search of something better, involved using what looked like the guy's belt wrapped around the aforementioned crank arm and chain stays.
Which was not a good solution for me because I wear suspenders.
Anyway, my first attempt, at devising something better, used a two-foot scrap of oak 1x3 cut into two one-foot lengths and with a hole drilled in the center of each to accommodate one crank arm and the adjacent chain stay, again clamped parallel with each other. I lined the inside surface of each of the oak jaws with 1/4" thick, self-adhering felt to avoid damaging the finish on the chain stay.
That worked, was easier to grab off the bench and install, but was still a little awkward and still allowed some of the movement made the belt idea unsatisfactory. Even if I wore one.
My next idea involved passing a 1x3x12" piece of plywood thru the spokes so that it lay on top of the two chain stays where it would be held in place by being u-bolted to the chain stay on each side. The crank arm would be immobilized simply by resting against the plywood piece secured to the chain stays.
However, after putting one of these together, I became concerned about the amount of pressure being transferred through the U-bolt and into the hollow aluminum chainstay.
Which led me back to the "sandwich" method, whereby two pieces of plywood would be passed thru the spokes, one above and one below the chain stays, with one of the cranks being sandwiched as well.
But that was gonna be a lot of plywood (or hardwood) in a limited space and so I jumped to a third iteration which used the same basic idea, trapping one of the crank arms along with the chain stays between a two-piece holder, but this time using steel C-channel which would be much stronger while taking up less space.
So that's what I'm gonna do. Not even gonna bother with the chop saw blade because it creates an unholy stink and a lot of heat whenever I use it in my small shop space, just gonna throw it in the cheapo plastic miter box and cut it by hand with my ancient hacksaw and a fresh blade.
After that, I'll step-drill the necessary holes on my Harbor Freight drill press, line the outside faces of the C-channel with the felt--because they'll be facing in against the chain stays--and secure them with socket head cap screws.
Anyway, that's the plan and I need to get at it because I've already lost some warm, dry days that could've been spent bicycling outside instead of indoors on "basement roads..."
LPK
Dreamwidth
5.25.2021
Because I don't have a helper, these days, I've had to make do with sandwiching the crank arm and chain stays between two pieces of scrap wood and securing this awkward assembly with c-clamps. And the only answer to my Google query, in search of something better, involved using what looked like the guy's belt wrapped around the aforementioned crank arm and chain stays.
Which was not a good solution for me because I wear suspenders.
Anyway, my first attempt, at devising something better, used a two-foot scrap of oak 1x3 cut into two one-foot lengths and with a hole drilled in the center of each to accommodate one crank arm and the adjacent chain stay, again clamped parallel with each other. I lined the inside surface of each of the oak jaws with 1/4" thick, self-adhering felt to avoid damaging the finish on the chain stay.
That worked, was easier to grab off the bench and install, but was still a little awkward and still allowed some of the movement made the belt idea unsatisfactory. Even if I wore one.
My next idea involved passing a 1x3x12" piece of plywood thru the spokes so that it lay on top of the two chain stays where it would be held in place by being u-bolted to the chain stay on each side. The crank arm would be immobilized simply by resting against the plywood piece secured to the chain stays.
However, after putting one of these together, I became concerned about the amount of pressure being transferred through the U-bolt and into the hollow aluminum chainstay.
Which led me back to the "sandwich" method, whereby two pieces of plywood would be passed thru the spokes, one above and one below the chain stays, with one of the cranks being sandwiched as well.
But that was gonna be a lot of plywood (or hardwood) in a limited space and so I jumped to a third iteration which used the same basic idea, trapping one of the crank arms along with the chain stays between a two-piece holder, but this time using steel C-channel which would be much stronger while taking up less space.
So that's what I'm gonna do. Not even gonna bother with the chop saw blade because it creates an unholy stink and a lot of heat whenever I use it in my small shop space, just gonna throw it in the cheapo plastic miter box and cut it by hand with my ancient hacksaw and a fresh blade.
After that, I'll step-drill the necessary holes on my Harbor Freight drill press, line the outside faces of the C-channel with the felt--because they'll be facing in against the chain stays--and secure them with socket head cap screws.
Anyway, that's the plan and I need to get at it because I've already lost some warm, dry days that could've been spent bicycling outside instead of indoors on "basement roads..."
LPK
Dreamwidth
5.25.2021
