Like always I have way too many projects going on. This one is in danger of being operational soon so I thought I'd make a post about it. I've been poking away at this for a year now. Off and on:o) It's a modern version of a old tandem bicycle. It will have Disc brakes, a 8 speed Sturmey Archer rear hub, and be welded up out of modern Chrome molly Steel tube.
Here is a page out of the catalog.
![](http://img.photobucket.com/albums/v652/Powderkeg3418/Columbia%2048%20tribute%20tandem/model47and48columbiatan.jpg)
I started with a front hub. I want this sucker to stop if needed so we built a hub that will hold 2 disc brakes. Here is how they started.
![](http://img.photobucket.com/albums/v652/Powderkeg3418/Columbia%2048%20tribute%20tandem/Columbia001_zps56605fc6.jpg)
A little CNC time and the disc brake bolt holes and the spoke holes were drilled. I also profiled the ends a little.
![](http://img.photobucket.com/albums/v652/Powderkeg3418/Columbia%2048%20tribute%20tandem/Columbia006_zps7116b68c.jpg)
Back onto my lathe and I found this under all that aluminum.
![](http://img.photobucket.com/albums/v652/Powderkeg3418/Columbia%2048%20tribute%20tandem/Columbia009_zpsbfe0b241.jpg)
![](http://img.photobucket.com/albums/v652/Powderkeg3418/Columbia%2048%20tribute%20tandem/Columbia008_zpsff9fc6c2.jpg)
I took the hub over to my buddy and he polished it up for me. He's a pretty great guy:o)
![](http://img.photobucket.com/albums/v652/Powderkeg3418/Columbia%2048%20tribute%20tandem/Columbia020_zps49302d20.jpg)
I think it turned out pretty good.
![](http://img.photobucket.com/albums/v652/Powderkeg3418/Columbia%2048%20tribute%20tandem/Columbia019_zps0b82e01a.jpg)
The eccentric bottom brackets that we bought had a ton of clearance in them. We thought it was too much and I decided to machine some new pieces.
![](http://img.photobucket.com/albums/v652/Powderkeg3418/Columbia%2048%20tribute%20tandem/Columbia003_zps6d5aefa3.jpg)
A little cutting and a lot of filing and these appeared\o/
![](http://img.photobucket.com/albums/v652/Powderkeg3418/Columbia%2048%20tribute%20tandem/Columbia004_zps7d3a4f36.jpg)
Here it is with the eccentric installed.
![](http://img.photobucket.com/albums/v652/Powderkeg3418/Columbia%2048%20tribute%20tandem/Columbia005_zps6efe0301.jpg)
The outside will clamp on the eccentric to keep the chains tight. We made some little clamp pieces. Here they are tacked into place. Later I will braze them on. After I braze them on I'll slit the bottom bracket and they will become clamps.
![](http://img.photobucket.com/albums/v652/Powderkeg3418/Columbia%2048%20tribute%20tandem/Columbia007_zps6440185b.jpg)
The drop outs on this will be the modern style. I turned these on my lathe and then milled a slot in each one. These are for the rear wheel.
![](http://img.photobucket.com/albums/v652/Powderkeg3418/Columbia%2048%20tribute%20tandem/Dropouts001_zpsa3516317.jpg)
I made some extras for my buddy.
![](http://img.photobucket.com/albums/v652/Powderkeg3418/Columbia%2048%20tribute%20tandem/Dropouts002_zpsfae121ad.jpg)
The frame went went together pretty fast. Another buddy of mine has a frame table and did most of the frame for me.
![](http://img.photobucket.com/albums/v652/Powderkeg3418/Columbia%2048%20tribute%20tandem/Columbia010_zpse8f2893f.jpg)
We made the chain stays out of 3/4" round tube. It is squished and dimpled so the tire clears it. The dropouts were tacked on. With the rear wheel we got everything close.
![](http://img.photobucket.com/albums/v652/Powderkeg3418/Columbia%2048%20tribute%20tandem/Columbia011_zpsd46d75e7.jpg)
My buddy has a jig to check to see if the dropouts were still lined up after welding. we were off a little.
![](http://img.photobucket.com/albums/v652/Powderkeg3418/Columbia%2048%20tribute%20tandem/Columbia013_zpsa2344b48.jpg)
A little muscle.
![](http://img.photobucket.com/albums/v652/Powderkeg3418/Columbia%2048%20tribute%20tandem/Columbia014_zpsc7c02380.jpg)
And we're good to go\o/
![](http://img.photobucket.com/albums/v652/Powderkeg3418/Columbia%2048%20tribute%20tandem/Columbia015_zps86f5dfe2.jpg)
Then we made the seat stays and welded them on.
![](http://img.photobucket.com/albums/v652/Powderkeg3418/Columbia%2048%20tribute%20tandem/Columbia016_zps8f0002fe.jpg)
An action shot just because:o)
![](http://img.photobucket.com/albums/v652/Powderkeg3418/Columbia%2048%20tribute%20tandem/Columbia017_zpsb4982088.jpg)
I think this bike looks neat because it has a set of upper chain stays. We got them welded on. They were some fork tubes that were lying around.
![](http://img.photobucket.com/albums/v652/Powderkeg3418/Columbia%2048%20tribute%20tandem/Columbia022_zps836560e3.jpg)
They turned out pretty nice:o) Here is the back wheel all laced up with the 8 speed and new shoes\o/
![](http://img.photobucket.com/albums/v652/Powderkeg3418/Columbia%2048%20tribute%20tandem/Columbia023_zpsc98b99dd.jpg)
Getting pretty excited now. She will be longer than the Queen Marry I think.
![](http://img.photobucket.com/albums/v652/Powderkeg3418/Columbia%2048%20tribute%20tandem/Columbia024_zps4da84bbd.jpg)
Here is where I am now. I'm picking it up on Friday and it will be mine to finish. I still need to get seats and pedals. I have to figure out the steering. This will steer from both seats so I need to make a linkage. I'll be trying to get this done pretty quickly.
Thanks for watching.
~Wes~