A few days ago my Revoslot car suffered a complete failure of its anglewinder spur gear...
IMG_3144.jpeg
The gear appears to have completely separated from its hub.
In looking for a replacement part I discovered Revoslot offers spur gears in two materials. 132slotcar does not carry them, but I found the replacement parts at LEB Hobbies. One, in Nylon, appears to be the original replacement part and sells for US$5.99. The other, in aluminum, goes for US$9.99.
The description for the aluminum part lists it as "Ergal" -- something I had never heard of. A quick internet search taught me that Ergal is another name for the alloy 7075 aluminum. It also mentioned that, "This aluminum alloy is typically used when exceptional mechanical robustness and lightness are required."
So I ordered the Ergal part, two of them in fact. I'm hoping to get better service life out of the aluminum gear, but that is not a given. Grades of Nylon used for gears typically are self-lubricating. Aluminum is not. While I doubt the aluminum gears will fail like the Nylon gear did, they may wear quickly since there is no good way to keep them lubricated. TBD.
Just in passing, I'll mention that a well-respected fellow racer told me that the tooth form of the original equipment Revoslot spur gear is not ideal, and is a major reason Revoslot cars tend to be noisy. Apparently the peak of the tooth form is too high and tends to bottom in the pinion gear. He has found that removing the excessive height of the spur gear teeth improves the gear mesh and reduces noise. He has also used the old trick of heating the gear while running it to further improve the gear mesh.
Since I have yet to receive the aluminum gears I don't know how well they'll mesh with the pinion gear. I may try smearing valve-lapping compound on the gears to see if I can quickly wear-in the replacement gear for a good, quiet mesh. I think valve-lapping compound works better than toothpaste, as it is specifically designed to abrade metal.
Ed Bianchi
IMG_3144.jpeg
The gear appears to have completely separated from its hub.
In looking for a replacement part I discovered Revoslot offers spur gears in two materials. 132slotcar does not carry them, but I found the replacement parts at LEB Hobbies. One, in Nylon, appears to be the original replacement part and sells for US$5.99. The other, in aluminum, goes for US$9.99.
The description for the aluminum part lists it as "Ergal" -- something I had never heard of. A quick internet search taught me that Ergal is another name for the alloy 7075 aluminum. It also mentioned that, "This aluminum alloy is typically used when exceptional mechanical robustness and lightness are required."
So I ordered the Ergal part, two of them in fact. I'm hoping to get better service life out of the aluminum gear, but that is not a given. Grades of Nylon used for gears typically are self-lubricating. Aluminum is not. While I doubt the aluminum gears will fail like the Nylon gear did, they may wear quickly since there is no good way to keep them lubricated. TBD.
Just in passing, I'll mention that a well-respected fellow racer told me that the tooth form of the original equipment Revoslot spur gear is not ideal, and is a major reason Revoslot cars tend to be noisy. Apparently the peak of the tooth form is too high and tends to bottom in the pinion gear. He has found that removing the excessive height of the spur gear teeth improves the gear mesh and reduces noise. He has also used the old trick of heating the gear while running it to further improve the gear mesh.
Since I have yet to receive the aluminum gears I don't know how well they'll mesh with the pinion gear. I may try smearing valve-lapping compound on the gears to see if I can quickly wear-in the replacement gear for a good, quiet mesh. I think valve-lapping compound works better than toothpaste, as it is specifically designed to abrade metal.
Ed Bianchi
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