I had planned to write this post after the 24th, but because many people were curious and contacted me to get more information regarding welding jig's and how they were made, how much did it cost and if it actually worked. I'll try to answer as many questions below, if I leave something useful out then just give me a hoot and i'll add it in there :)
MDF/Plywood welding jig
If you are planning to build between 1-3 frames for your own use, I'd suggest using the following jig. While it is only meant to last the welding of a few frames, the cost and simplicity of manufacturing offsets the short lifespan. After about 3 frames, the jig is too soft to use. The main issue was that due to the softness of wood, the frames would come out crooked.
Manufacturing/machining the jig:
Cutting files and model can be found here: bicycle frame welding jig
As for machining the jig itself, I reccommend contacting a local wood working shop, furniture building company or a metal company with a CNC router or a waterjet cutting aparatus(note that plywood can be cut by a waterjet, MDF cannot, as it will absorb too much water and become distorted after a few days as it dries out).
Drawings: please send me an email or message here or reddit, to get the drawings - can't attach them to the blog directly :(
Cost and bill of materials:
- 1 sheet of 18/20mm plywood or MDF. 0.7 to 0.8 inch thick to our american friends :)
- M10 and M6 screws, 40 mm lenght. Unfortunately i have no idea about inch thread sizes, its about 0.35 inches of bolt thickness for M10 and 0.22 inches of bolt thickness for M6. lenght would be 1.5inches. if you want better results, you can buy a few washers too.
- 2 quick releases, 1 front wheel and 1 rear wheel. The front wheel one is used to secure the bottom bracket, rear wheel one is used to secure he headtube(allows a maximum height of abot 145mm)
- a jar of good wood glue
- some wood screws(make sure you drill atleast a 2.5mm or 0.1 inch lead hole to reduce material splitting)
- about 1-1.5 hours of your time and a good mood
Since I had all of this lying around the house, it cost me roughly 30bucks/20 euros to get the parts CNC cut by a local wood shop. If you have to buy everything from skratch, I'd estimate the cost to be around 75 bucks/55 euros. Works fine for first prototypes and gives you a good sense of how difficult building these things really is - (its not :) ).
Build order:
- start by finding the material to cut the jig blanks out of. Plywood or MDF will do fine.
- after you have gotten your material, take it to a place that will cut the blanks out for you. after accomplishing this, give yourself a pat on the back and have a break, this is the hardest part.
- go buy your bolts, washers(if needed), wood screws and some good wood glue
- start preparing your parts for assembly - sand rough edges, clear holes and give them a gentle sand to remove any collected particles.
- drill lead holes into the headtube and seat tube (detail B-01, B-03 and B-04) and into 1 B-02 spacer block. after drilling is done, line the blocks up, add some wood glue in between and drive the screws in. wipe excess glue to make it look nice and make sure to check that you have a 90 degree angle(+/- 1 degree is fine).
- with M10 bolts, the thread is quite coarse, so i decided to forgo any anchors and just threaded the bolts into the MDF. If you dont overtighten the bolts, it should hold adequately to complete a few frames.
- you may have noticed that the rear axle block is missing completely - that was substituted by a M10 thread rod with some nuts and bolts spaced at strategic positons. When i needed to change chainstay length i just unsecured one bolt and slid the thread rod/nut assembly up or down the slide - easy peasy.
- When using quick releases to secure either bottom bracket or headtube, use an anchor ( picture) - thread is too small to drive it directly into the material. In europe, the quick release thread is M5 - not sure if its the same for the US and CA.
- After getting everything secured and bolted togeather, make sure you check all angles before welding - this will avoid getting crooked frames.
I'm sure I left something out, so if you start the build and hit trouble, just send me a hoot and I'll give you a helping hand.
As an added bonus to the people who made it to the end - a singlespeed frame design I've been working on - feedback much appreciated :)
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