Rear Forks

Clamped to weld on rear forks ...

With the front forks, the rear forks, and a couple of wheels mounted, it is starting to look somewhat like a recumbent bicycle ...

Now it just needs dropouts, derailleurs, crank & pedals, A SEAT, handlebars, and a chain.

Start of Rear Forks

Here the main tube is clamped in the jig.
The black forks on the left will be used for rear forks.
Notice that I cut the head tube off about 3/8's inches below the bottom bearing support. This is so that I can use it for a steering unit in another project. And leaves enough room to weld the tab on it below the bearing to connect to the front forks.

I still have to mark and drill the holes near the rear of the main tube (on your right in this foto) ... and build the block to hold the axle-end of the forks in position when I clamp the main tube on the other side of the jig to weld the forks to it at the proper angle (those two empty "u" blocks over there will hold the main tube with the bottom bracket hanging downward over the right end).

Bentech Step 2-1/8

Main tube with head tube clamped in the jig.
The drill thing is what I used to drill the hole for the head tube.
White u-strip will be welded on for the idler wheels
to get the chain up and out of the way of the front fork.

Here the u-strip has been welded on ...
and you see the two chain idler wheels.
The idler wheels were skate wheels that I turn on my drill press.
the blue thing is just a temporary spacer ...
because I didn't have another 2" x 5/16' bolt.

Here's the current status of the main tube ...
the portion to the left of the head tube will be shortened a bit
when it is tweaked and bored for the bottom bracket.

Bentech Step 2

The main tube has been shortened, I marked the centerline of the sides of the tube, marked the head tube points, center-punched them, used a 1/8" drill bit and drilled pilot holes, then used a bi-metallic holesaw with a 1/4" center bit to drill from each side ...
to drill out the hole for the head tube.

Here I've tack-welded the head tube into postion. You may be wondering how the decision was made as to how much of the head tube would protrude above or below the main tube ... I took off the front end clamps, loosened the 2 clamps to my right, rotated the front end of the main tube 90° up, tightened down the 2 clamps to the right, inserted the head tube so it rested squarely on the surface of the jig ...
I tacked on one side, then directly 180°opposite on the other side. Then the two opposite ones for front & back.
The white u-bar will be the bracket for the chain guide idler wheels.

Here's a view of my welding ... dressed up by the hand grinder.
The head tube is now firmly in place.

Bentech starting

I've built one of these before.  This was made with a muffler pipe and a Huffy Mtn bike (the Huffy front forks became the rear forks on the Bentech SWB).  I had USS (under seat steering) on it.  It ended up being a favorite bike due the ease of transporting it and because of sitting high enough that I was quite visible in traffic.  That's very important when you are riding through a BIG city.
Anyway, back to construction ...

Here's the maintube (muffler pipe again) clamped in the jig.
This tube is a little long ... I could only buy a 10 ft. length,
so I had it split into two 5 ft sections ... a muffler shop did the bend for $2

This is just the start ... shortening & drilling comes next ...

Jig - Update

The blocks are mounted on the jig.
The tubing lays in the center of the blocks
and is clamped by screwing down the top half.

I've lifted the tops off ...
and you can the bottom half's are screwed to the jig surface.
Nest Step: get 1-3/4" muffler tubing

Drilling Jig for Hubs & Axles

I made this little jig so that I could consistently and easily drill the corresponding holes in the hub and the axles. The jig is made from a piece of old bedframe. Notice that when I drill the hub, I insert one of the AN970 washers

that has been cut to fit the "V" of the jig. When drilling the axle, I remove the washer so that I can accurately drill the correct location that the hub would fit on the axles with just the tip of the axle showing with the outside washer on. Do you understand what I just attempted to say? Ok Fine. :0)