On Bending

I think I have a lead on getting my fork blades raked.  It's probably not going to happen until this weekend, so this week will probably be a little slow - I can finish the steerer joint, but after that I have to wait on the blades before I can continue work on the fork.  In the meantime, let's look at the different options I've considered for bending blades.

Talbot makes no mention of how to rake fork blades, because he was able to purchase pre-raked blades for the frame he builds in his book.  I have not found any source of bent fork blades, which means that it's up to the builder to do this work.  Without a large work shop and heavy machinery, I'm at a bit of a disadvantage.

The first plan I had in mind was based off of this builder's fork bender.  I went to the local woodworking shop and got a heavy piece of maple.  Cutting it with a jigsaw, I realized that the wood was slightly warped, meaning that the saw did not make a flat cut.  I could have solved this problem if I had a wood plane.  A second problem arose - how do I cut a groove in the wood to accept the tubing?  I was unwilling to purchase a router (or router table), and hand methods would have taken a considerable amount of time - not to mention being inaccurate.  So, scrap this idea for now.  I may continue to work on it for future bikes.

Some more research put me on to the idea of a conduit bender.  These tools are used to shape electrical conduit, and it looks like recumbent builders have put them to use increasing the rake of previously fabricated forks.  Off I went to Chasen Industrial Supply, who have a terrible website but a really fantastic set of folks on staff.  Unfortunately, after talking the idea over with the folks at the store, they convinced me that I was very likely to crush or kink the tubing trying to use a conduit bender; conduit is much thinner and more malleable than the tubing for a bicycle fork, and the benders just don't seem to be up to the task.  (Although, if you have any hard experience successfully bending a straight fork with a conduit bender, let me know!)  They did have the Dykem I was searching for, though, so the trip was not all in vain.

When I got home, I called around to some of the bike shops and fabricators in the area.  Independent Fabrication told me that they only use straight blades (the rake is achieved with an angle at the crown).  I also called the Broadway Bicycle School in Cambridge - they have an open shop that one can rent by the hour.  They don't have the tools, but they did suggest calling Geekhouse Bikes in Allston.  I left a voice mail with them, but also surfed through their Links page to Royal H Cycles in Somerville.  Bryan told me he'd be willing to rake the blades for me with his homemade bender for a nominal fee.  This is the route I'll be taking for now.

What other options are there?  Nova Cycle Supply sells a bender for $375, which is outside my price range for this project (especially considering the likelihood of being able to resell the tool is pretty minimal).  Finally (and the option that I'm most attracted to but least equipped for), I could make a bender out of metal.

Homemade benders that I've seen online tend to have a large radius curved metal block with a groove in it for the tubing - similar to what I was trying to make out of wood.  They also have a long handle that is pinned to the block so it can rotate around the curve; the handle has a roller on it that guides the tubing around the curve.  Making something like this would require a machine shop - at the very least a mill, which I don't have the money or space for.  However, there is a new community workshop opening in the Boston area which should have the capabilities I would need.

I feel a little chagrined about not bending the blades myself, but I'm coming to terms with the idea that it's ok to outsource when you don't have the capabilities yourself (I'll let someone else paint the bike, for example).  Maybe after visiting Royal H, I'll have a better idea of how to build my own for future projects.

I also wanted to share an acronym I learned from the framebuilders e-mail list - SOPWAMTOS.  It stands for "Society Of People Who Actually Make Their Own Shit", and I'm obviously not following the spirit of it by not building my own tooling.  One day!