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How to Rivet an STI Cable Stop

November 13th, 2011 [print] No comments

In the process of modifying my Scrambler frame with cable stops, I ran into a problem:  how to rivet the stops in place.  Seems easy enough on the surface, but what I soon found was it’s impossible to get a rivet gun flat against the rivet heads.  In case anyone else has run into the same problem, I thought I’d share my method.

First, let’s do the brake cable stops.  Whether you’re going with standard ones, or the type that hold hydraulic brake lines, it’s pretty simple.  Drill a couple 1/8" holes where you want the stops.  Be very accurate with your measurements before you drill.  If the holes aren’t lined up with the holes on the stop, you’ve more or less just ruined your frame.  In fact, if you’re even off by a fraction of a millimeter, the rivets may go in, but end up a little crooked, and look like crap.  Use a center punch so the drill bit doesn’t walk, and drill a smaller pilot hole first.  I’d also suggest using aluminum rivets, since they’re lighter, don’t rust, and require less force to rivet than steel.

You’ll need rivets 3mm x 3mm in size, and they’re easy to find at any hardware store for about $5 for 100 of them.

Okay, here’s the problem you’re going to have:  once the holes are drilled, and the stops are zip tied in place, you’re going to realize there’s no way to place the head of the rivet gun flat against the head of the rivet because it’s in a recessed area.

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Here’s the solution:  go to a hardware store, like Ace Hardware, etc, and buy a couple aluminum spacers 1/2" long and 1/4" diameter.  One of them will need to be cut down to about 9mm long for a standard cable stop.  Use a fine tooth hacksaw blade and a vise to cut it, but save both pieces.  Also, be sure to compensate for blade thickness, because you really need it to be 9mm long so that it clears the stop, but allows enough of the rivet pin to stick through so the gun can grab it.

Now, put the rivet in place through the stop and frame, and slide the 9mm spacer down the rivet pin.  It will rest against the rivet head, and give the rivet gun’s head something to push against.  A couple squeezes of the gun handle, and the pin should break as the rivet permanently clamps the to objects together.

(Tip:  wrap electrical tape around the entire area, because once the pin breaks, the gun may fly forward and ding the frame or scratch your paint.)

The brake cable stops were the easy part, but the STI stop will take a little more effort.  For the record, I didn’t come up with this idea.  I racked my brain for days trying to figure out how I’d get the STI stop riveted on, since putting enough spacers in place for the gun to clear the stop, meant there wasn’t enough pin exposed for the gun to grab onto.  I mentioned it to a guy I know, and he came up with an idea that saved my day:  pull the pin out of a longer rivet, and use it in the shorter one.  I had no idea the pin could be removed, but it can…

I headed back to Lowes, and bough a box of 3mm x 1/2" rivets, since that was the longest they had in 3mm diameter.  If you can find something longer, go for it, but 1/2" gets the job done.

Next, it’s time to do some pin swapping.  Unlike steel rivets, where the pin easily slips out by hand, it’s in there a lot tighter in an aluminum rivet.  I ended up using an adjustable wrench–wrapped around the rivet, just under the head–to press the rivet off the pin, against a hard tile.

This first photo shows how the pins are the same length above the heads, but it’s much longer under the head on the 1/2" rivet.

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With the rivets pulled off the pins, you get an idea how much longer one is than the other.

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Next, do the swap, again using an adjustable wrench to force the pin onto the rivet.

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Now, it’s time to add some spacers.  Remember that piece I told you to hold onto from the cut spacer?  Well, slip it, and the uncut 1/2" spacer onto the rivet pin, and you have enough to clear the taller STI stop, with enough exposed pin for the rivet gun to grab onto.

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You can discard the leftover 1/2" rivet and shorter pin.  When you’re all done, you should have something like this:

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One other thing I’ll add is, if you’re doing this to a steel frame, put a tiny bit of grease around the edges of the holes you drilled in the frame, and between the frame and the stop.  It’ll work as a water-tight barrier to help prevent rust.  That’s a little bit of grease being squeezed out near the upper rivet in my photo, so I know I have a good seal.

Links:

Standard aluminum brake cable stop (also in black)
STI derailer cable stop
Standard rivet gun

EighthInch Scrambler Update pt2

November 13th, 2011 [print] No comments

In my previous post, I stripped the paint off my frame, sprayed on some primer, and was beginning to sand it.  Well, I eventually got around to painting it, but I wasn’t happy.  Even a perfect spray paint job still looks like spray paint, so I took it to a professional and had it powder coated 80-90 Jet black.  One upside to powder coating is, the powder melts very nicely into the welds.  This frame always had crappy looking welds, so now they’re a little easier to look at, although I doubt Gary Klein has anything to be jealous of.

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The sad part is, I spent more time fucking around trying to paint it on my own, than I did driving back and forth to the powder coater in a city about 40 minutes away.  The guy who did the work was Jeff at Xtreme Body & Paint in Jefferson City.  He was really easy to work with, and does awesome work.  Turn around time was a mere 2 days.

Once I got the frame back, I had to visit my local bike shop to get the BB threads chased, and the head tube re-faced, but that’s to be expected after any paint job.

Since I’m running a front derailer now (and because I don’t want to run full-length cable housing) I decided to install an STI cable stop on the downtube, and an under-BB cable guide.  I got both parts at Nova Cycles for just a few bucks.  For the STI stop, I used a 1/8" drill bit and some 3mm x 3mm aluminum pop rivets.  The cable guide needed to be screwed on, so I drilled with a 5/32" bit, and used a Park TAP-8 5mm x .8 tap.  Installing the guide was as easy as it gets, but the STI stop took some work.  I’ll mention how I got that on in another post.

You’ll notice I also have rear brake cable guides, so I never have to zip-tie full housing to the top tube ever again.  I installed those prior to painting, and once the powder coat melted all around them, they look like part of the frame.  I intentionally left the STI stop off until after the paint job, because I didn’t want paint–or powder–to get inside the threads.

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Unfortunately, along with some pretty easy mods, I’ve also had some very annoying issues.  Because I’m turning a track bike into a 2-speed cyclocross bike, I’m having clearance issues, most specifically with the tires.  I verified long ago that some 32c Kenda Kwicker tires fit the frame and fork, but what I wasn’t expecting was for them not to clear the Cane Creek SCR-3L brakes I just bought.  Due to the design of the calipers, the mounting bolt is higher on the body than it was on my Alhonga brakes, meaning the brakes hung too low below the fork crown and rear brake arch.  Because of this, 32c tires rubbed big time, so I had to order some 30c Kenda Kwick tires instead.  BUT, I wanted 32c, dammit, and I wasn’t about to give up.  Currently, I’m waiting on a set of Tektro R538 brakes, which should give me the clearance of the Alhongas, with the reach of the Cane Creeks.  Once I get that worked out, I’ll be able to use either tire, depending on where I’m riding.

As for other clearance concerns, they all seem to be working themselves out quite nicely.  My biggest concern with running a non-track crankset with dual chainrings is, the inner ring may come in contact with the frame.  As it turns out, I have about 4mm clearance between the chainstay and a 39T ring on my SRAM Force cranks.  It’s tight, but that’s more than enough room to get by.

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My other issue was whether a water bottle bolt would get in the way of the front derailer clamp, but I have just enough room to make it work.  I can’t use that bottle mount anymore, but I don’t think I ever have before anyway.

I did luck out with my rear tensioner set-up, so I’m happy about that.  I’m using a Paul Comp. Melvin tensioner, with a DMR chain tug, which includes a rear derailer hanger.  The Melvin has 3 spacers to help align the pulleys, and once I was finished configuring them, alignment was perfect.

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This is basically where I sit for the time being.  I’m waiting on an STI barrel adjuster and the Tektro brakes.  Once those pieces arrive, I should finally be able to go for a ride.