Inner Chain Guide on the cheap! Homemade!

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Inner Chain Guide on the cheap! Homemade!

Postby Tomcat65 » Mon Sep 15, 2014 8:34 pm

I should have named this "How to lose a finger while working on your bike!"

Anyways, I do not suggest that you try this at home, I do not say that you should work without proper safety equipment, I do not say that you should ever do ANYTHING I do lol..

But this is how I made mine :geek:

The material is a PVC trim board that I bought from the Home Depot, Lowe's or Menard's.. I have no certain recollection where it came from, it's leftover. Which makes it free! All the better! It machines easy, easier than wood, because there is no grain to deal with and it's fairly durable. I would Not trust it as a bash guard alone because it isn't super strong, but used along with a bash guard, I believe it will hold up. This is a spare that I made though, just in case.

First things first, I found the center and punched it with an awl.
The smaller chainring has a 64mm BCD = Bolt Circle Diameter, so I set my compass to 32mm for the radius and pressed on.
Rough cut on the miter saw, Then on to the drill press.
Inner chain guide 1.jpg
Inner chain guide 1.jpg (151.38 KiB) Viewed 53 times

Once again, I do NOT recommend that you do Anything I do! But I have found a way to cut dang close circular cuts on my table saw :) Raise the blade a little at a time, turn turn turn, not all at once, might take 3 or 4 shallow cuts and I'm using a guide...
Router table, got to bevel the edges, both sides, so the chain will center AND, so the back side doesn't rub the frame.
A 2 1/8" forstner bit centered to clear the bottom bracket, and then a 3/4" to countersink the crankset's smaller chainring mounts. I set my drill press to a depth and checked it... I am not listing a depth because results may vary and YOU aren't supposed to be doing this anyway.
Inner chain guide 2.jpg
Inner chain guide 2.jpg (237.3 KiB) Viewed 53 times

Just about finished, I have a sheet of sticky sandpaper mounted on a smooth piece of plywood. I rubbed the chain guide round and round over it until I was satisfied that my marks were all gone. The second one took me about 30 minutes. Even with this spectacular photography! It's cheap, it's ugly, it's just about too dangerous to post... if it were Old, It would be a Lot like me!

Finished product:
Inner chain guide 3.jpg
Inner chain guide 3.jpg (362.77 KiB) Viewed 53 times

Dead serious, Just about anyone can make one of these, but Safety must be a consideration. I did remove some blade guards so I could get better pictures and I do put myself at risk sometimes, but I'm not one to take these machines lightly. If you decide to make one of these, post some pics!
Best of luck!
Godspeed your bikes boys!
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