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Unexpected use of FR2 of the week: Phenolic gears (aussie.zone)

submitted 9 hours ago* (last edited 9 hours ago) by [email protected] to c/[email protected]

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FR2 is the brownish material that many cheap circuit boards are made of. It's a mixture of phenolic resin and paper. Apparently it's quite useful to make gears out of:

Phenolic Gears exhibits superior shear force, help reduce machinery noise, absorbs destructive vibration unlike metal gears, phenolic is non-conductive, protects the mating metal gear train, and are known to outlast metal gears under severe continuous service. (source: https://www.knowbirs.com/phenolic-gears )

(Main pic stolen from here)

(Many more pics here)

Has anyone seen these used anywhere? I've read a hint regarding pool equipment, but I have never seen them there. I assume the fibres allow them to last longer than plastic/resin only gears.

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[–] [email protected] 1 points 2 hours ago* (last edited 1 hour ago)

Old big EMCO lathes had phenolic gears in their gearbox. I know because I got to rebuild one and that was one surprise I came actross and that day I learned about phenolic gears.
Probably also useful as a safety shear point. Better to grind a phenolic gear to dust that to break something expensive.

Also I will never forget the smell of the gear oil.

[–] [email protected] 4 points 5 hours ago

Older engines had them in their timing gears - they were in 6 cylinder Holdens, for example.

They give an amount of cushioning/vibration dampening that you can't get with steel gear sets.

[–] [email protected] 2 points 5 hours ago (1 children)

Woah those are some cool properties, I wonder how hard these gears would be to manufacture at home? I'm looking at implementing my own custom gear reductions in servos but I don't think my 3d prints will mesh well enough or withstand long usage

[–] [email protected] 2 points 4 hours ago* (last edited 4 hours ago)

There are some youtube videos of people machining them (sadly my browser does not support smell). Looks like you treat it like any other solid material: hobb or mill the teeth. This is much more expensive than 3d printing.

You might be surprised by your 3d printed gears. If you keep the detail size large they work really well, but backlash is definitely an issue.