Sandblasted canti posts
[Cross-post from mechanics, since I know there are a lot of technically-savvy people here, and it's a tandem frame]
So, I took my frame to be powdercoated, and the powdercoaters sandblasted the cantilever brake posts while stripping the frame. The brakes seem to fit and pivot OK, but the posts are definitely "stickier" to the touch than they were before. I'm wondering if I should do something to polish them back to a smoother finish, and if so, what? Any suggestions?
some post are bolted. i hope the ones on your frame are these type so you can just replace them.
otherwise just polish it with fine steelwool. you can also go the extra mile by using a Dremel polishing compound and attachment.
I would imagine that if you took some fine (~400) sandpaper and worked each post around (e.g. same direction as the motion of the brakes), you should be able to get smoother motion without removing much material.
That will do fine if you're worried about it. Otherwise, just grease the post & install the arms.
Originally Posted by oldacura
Where you may experience some difficulty is where the canti post meets the rest of the braze-on.
A lip of powdercoat may hang over enough that all looks good initially, but when the fixing bolt is tightened, the brake arms are sticky or won't pivot at all.
Two possibilities; the lip of PC, or the arms have been removed/installed enough times to actually shorten the post a bit.
In which case, I have a neat little tool...a canti boss facing tool!~
See picture #26 here... http://www.flickr.com/photos/owhn/se...7608666766179/
Checking if I can link the image in.
I did not know they made such a tool. Of course you would own one Dr. D
Originally Posted by dsmyers
Originally Posted by dr.deltron
Actually, I am getting some binding when I tighten the bolts down fully, so I'll check for a PC lip and probably take the bike by a shop--I don't want to risk the brakes falling off due to insufficient tightening of the mounting bolts . Thanks for the suggestion.
Originally Posted by Dr.Deltron