Bonney Fin -Twister

[Papaw]

Is this for straightening radiator or A/C fins?

[oldgoaly]

All the fin straighteners I have a plastic, from the mid 1970's.
That looks like much older? 1950's?

[lptools]

Hello, Papaw. I can't help with your question, but that is a great example of a seldom seen tool.Thanks for sharing!!! Regards, Lou

[p_toad]

Cute.   Found the following ad in the Google books search for Popular Mechanics Nov. 1924....

[gibsontool]

Nice item. I've heard about these but never seen one. Very cool.

[bonneyman]

Gotta be an old tool, I can't see modern coils thin aluminum fins responding well to that thing.

All of my A/C fin combs are plastic, so they are softer than the fins and take all the wear. Have a whole set of 'em, with various FPI (fins per inch) that snap into a composite handle so you can tailor the tool to each individual coil.

Like this:

https://mainsupplies.com/coil-fin-combs/

[mvwcnews]

Up until auto radiators got "hid" behind grilles of one kind or another  the fins would have taken a beating.

[oldgoaly]

I'm thinking the honeycomb style radiator was common in to the 1920's, when did the straight finned ones take over? also in the 20's?If I can remember to ask the radiator guru on facebook I'll find out.