Paint delays and Part 2 of How I build a bike

Folks, due to the extreme humidity and heat this past week, we have had some paint delays. The decals tend to bubble and the clear has issues of its own in this kind of weather. The weather is going to be more mild this week and painting will be complete on Jim's and Francis's framesets.

Last time, we left off with a completely machined tubeset, except for the seat stays. Next, we set up the jig and mock up the tubes to check all of the fits. Here is the frame in the jig with lugs installed.

What's goinig on under the lugs? Well, have a look...

Nice, tight mitres. Again, quality machining leads to a straight bicycle frame.

Here are some pictures of the joints with the lugs and the dropouts.

Here you can see what I mean by the "hollowed out" BB shell. No extra material hanging around.

I still do the seat stay miter by hand with a file. It's roughed in on a grinding wheel and finished with the file.

And here is the fit up in the lug.

Next time, I'll show the braze ons and tacking.

How I build a frame

I started this blog with the intent to show my readers how I fabricate frames and forks. The blog has morphed a bit to become a place to update customers on progress. I will keep the progress reports coming, but I want to get back to my original plan. I have taken a lot of photos of the build process of Nathan's bike, and I will lay them out in installments. This first installment shows the first steps of machining the tubes and prepping some of the castings.

First step is to give the new frame an identity. And not just some cold number, but a name to go with it.




Here are the materials all laid out. Tubing from left are seat stays, chain stays, down tube, seat tube, top tube, head tube. Note the markings on the main tubes. Those indicate the butt transitions where the tubes go from thick on the ends to thin in the middle. The rear dropouts and seat stay bridge are shown on the left. The lugs and BB are on the right.

I begin with rough cutting the chainstays to length.

The chain stays are then set up in our tube mitering fixture.

The next tube to be worked is the seat tube. This tube has a double cut. The first cut gives the shape of the inside of the BB shell.


The next cut makes room for where the down tube and seat tube overlap. This cut is at 90 degrees to the first cut and approximately 60 degrees to the down tube. The rotory table sets the ST/DT angle and the upright peg sets the tube perpendicular to the first cut.

The next tube is the top tube. The first cut is made at approximately 73 degrees.


Next, the cut length is set on the fixture. You can see here that the tube needs to be rough cut to length.

The cut length is set on the leading edge of the block. This is a 58.1 cm top tube.

This precision turned dowel is set on the fixture and the tube is butted against it. This dowel is parallel to the cutter. This keeps the miters in perfect plane with each other and helps create a straight frame.



Next is the down tube. There are 3 cuts on the down tube. One where the tube butts against the head tube, one to give it the shape of the inside of the BB shell, and a third where the seat tube and down tube overlap. What's that you say? Didn't we take care of that with the second cut on the seat tube? Yes, but I hate looking into the shell and seeing a piece of tubing just hanging there not doing anything. So I cut it off. And then when you look into the BB shell, all you see is a nice, clean interior.

The first cut is the BB end of the down tube. A simple 90 degree cut.

The down tube cut length is set and the peg sets the tube perpendicular to the first cut.



Next is the third cut. A pivoting dowel is again used that is parallel to the cutter.

And then the third cut is made.


Here is the completed main triangle and chain stays. The rest of the braze-ons are also laid out.

In the next installment, we will mock the frame up in the jig and maybe do some tacking.

Lots of good stuff going on at the shop. It's been full bore. These three are in process at paint, with six others close behind. I will have pictures of bikes for Nathan and Francis this week.

This one is headed to PDX. Jim's new cross bike has Slant Six lugs and Columbus Niobium tubing. I am building the fleet out there on the west coast. I know Jim will race it really hard.

Good luck this season, Jim, and thank you for your order!

Here is Scott's new Steelhead. Slant Six lugs, fastback seat stays, straight blade fork...very racey looking.

Thank you, Scott!

I always want to build at least one mountain bike a year. Well, here is the one for 2007.

Thanks, Donny!

Here is the updated schedule. Due to be complete in August are the three frames above and framesets for Nathan B, Francis B, Don F, Eric G, Steve P and Dianne E. In September, the order is Ryan R, John C, Matt M, Kerry C, Mike H, Kenny A, Mark A (RBR Charity Bike), and Jeff U.

Have a great week!