Christian's Custom Mountain Bike
Built with chromoly double butted tube and fully tig welded together in the home shop.
The project was from the ground up starting with a custom frame jig out of leftover aluminum extrusion and some machined fixturing for the tubes and bottom bracket.
Its a 29″ wheel and 150mm font fork. I kept parts cheap from Ebay as I wasn’t sure if it was going to work out being my first mtb frame.
The geometry of the bike was based on a popular model that i found all the details for online. measurements were done using a digital angle and tape measure, so fairly rough, but in the end it rides and feels nice and easy to control.
I started by welding the front triangle together and then moved on to the rear frame
Learned a fair amount during the entire process. For my next frame I will certainly be 3d printing some tube clamps to better hold in the vise and to get the compound angles correct, Also I put to much heat into the welds as its fairly tin wall so should have practiced more on test pieces. The biggest learning I had was to put vent holes for fully closed up tube sections, all that heat expanded the air inside and when going to close up the final weld I did have a blow out on two of the tube making for a ugly fix.
Between the old mill, lathe and some hand files I was able to make everything needed to get the frame together and straight.
In the end it rides great, handles well and looks really cool unpainted, plenty of questions from strangers about what type of bike it is. Besides the learning mentioned above I think I’ll add a head tube bracket for more support, and stiffen the rear brake mount. Maybe for the next one I’ll try and do a full suspension…
