Fig. A: Legs and dropouts cut from the original fork.
Fig. B: Grinding out too much of the crown would make
the fork legs too close together for a front wheel, and
would invite major warping in the pipe while welding.
Next, bolt the dropouts back onto the front wheel,
making sure they’re perfectly parallel. If the flat
parts are not in line with the tubes, straighten them
with a pair of pliers.
With your new fork laying on a flat surface next
to the upright front wheel, position the dropouts so
they hang down and touch the ends of the fork legs.
Tack-weld the dropouts in place, then check alignment by looking at the assembly from all angles,
especially lengthwise. Correct any misalignments
with a small hammer, and then complete all the
welds, starting with the dropouts. Keep checking
the alignment as you weld.
With both wheels attached (Figure D), insert the new
fork back into the frame and look at the geometry.
Most likely, the bike will lean back and the bottom
bracket will be very high, creating a “skyscraper”
style chopper. Although the bike would be rideable
in this configuration, I decided to mod the frame in
order to lower the bottom bracket. Since I planned
70 Make: Volume 11
Fig. C: New fork legs tack-welded in place on either
side of the original fork crown.
Fig. D: Welding the dropouts to the fork legs.
to remove the top tube and convert it from a
women’s frame anyway, this wasn’t a big deal.
Using the cutting wheel, cut the top tube from
the frame at the thick part of the lugs at both ends.
Cutting it flush with the head and seat tubes would
make a mess, and you can use the thicker part of
the lugs to your advantage later.
The down tube needs to be bent upward to keep
the bike from leaning too far backward when you
add those long forks. The amount is up to you. If you
like a tall chopper, try bending the tube upward 10
or 20 degrees. If you want that low-and-lean look,
you could bend the tube farther, but be careful
of how close the pedals may come to the ground.
When in doubt, lay all your parts down to get a
visual plan in your mind before you make a radical
To adjust the down tube, slice a thin, pie-shaped
wedge out of the top of the tube and bend it up to
fill the gap (Figure E). If you make your cuts even
on both sides, then the tube will bend up easily in
perfect alignment with the rest of the frame. After