Gettin' Jiggy With It

Time to start cuttin'!  I need two jigs for the bicycle fork - a blade bender and a layout jig.  You can purchase professional ones for several hundred dollars, but for a home workshop that's overkill.  Keep in mind that the total cost of your bicycle includes more than the raw materials; every tool, all the consumables, even the electricity to run the lights add to the cost.

I found a perfect piece for a layout jig at Home Depot:

On the left is a pre-cut shelf made of MDF, about 15"x36".  On the right is a 1"-ish thick piece of maple, about 8"x12" that I got at a local woodworking shop.  The maple will become the blade bending jig, since it's strong enough not to deform while exerting a concentrated compressive load against the grain - as I will when I'm trying to wrench a metal pipe around it.  Using a string compass, I scribed an 8" radius at one end for the bend on the fork blades.  Hopefully there will be enough scrap left over that I can make a tube block to hold the blades.

The MDF shelf needs three operations done on it: attach a clamping block for the steerer, cut a window out for the crown, and attach a block at the bottom for the dropouts.  The dropout block will have a threaded rod through it so that the dropouts can be "clamped" in place with a set of nuts; this will hopefully properly set the distance between the dropouts and keep the whole fork in alignment while it's being brazed.

I scribed marks on the shelf:

The line down the board marks the center of the shelf.  To be more "proper" with my marking, I should have scrawled something in the window - a zig-zag line or the word "CUT" to show what's being removed.  The line at the bottom is where the dropout block will be placed.

There's some scrap wood in the basement, so I took a piece and cut the blocks out of it:

It's not large enough to provide the proper height for the dropout block, so those two small pieces get glued together:

Some wood glue and a clamp, then leave to dry.  The cuts were all made with a hand saw I had lying around and are a little crooked, so I have to go back and sand them flat.  The dimensions of the blocks aren't terribly critical - the spacing for the dropouts will be accomplished by moving nuts on the threaded rod that will be in the dropout block, and the steerer block only needs to be long enough to securely clamp the steerer to it.

Mocking up the jig:

There's a problem with this.  The steerer block actually should not be adjacent to the centerline of the board like that; because the centerline of the steerer tube should be coincident with the centerline of the board, the block actually needs to be 1/2" to the left (I have a 1" steerer).  Luckily, nothing is attached yet.  I did actually make a drawing for the jig with the correct offset, but failed to copy it over to the board.

I don't actually have the tools to cut the window in the jig (or the radius on the fork bender), so it's off to a friend's house to borrow his scroll saw.