Strengthening ridges
Making a ridge with a spring jenny
Practical Action
Eye bent round for
stability and fixing
Steel rod
Wood base
Moveable
steel rod guide
pegs to hold
bucket against
while working
Holes for
movable
guide pegs
‘Male’ tool
made by
bending rod
round so that it
lies between
the two steel
rods.
‘Female’ tool made
by fixing two lengths
of steel rod straight
across, apart so that
the ‘male’ tool just
fits between the two
steel rods when
pushed down.
Making the ridge
1) Place guide pegs in
equal holes, to guide
where the ridge will
be made.
2) Place rim of the
bucket against guide
oegs, so that the
outside of the bucket
presses down against
the female tool, so
the male tool is on
the inside of the
bucket.
3) Strike the top of the
male tool repeatedly
with a hammer or
mallet, and rotate the
bucket slowly as the
ridge is formed,
taking care that the bucket rim always rests against the guide pegs.
4) When ridge is completed, move guide pegs and repeat the process for another ridge.
References and further reading
• How to Make a Folding Machine for Sheet Metal Work - Workshop Equipment 1
Rob Hithings, Practical Action Publishing
• How to Make a Foot-operated Workshop Drill Workshop Equipment 2
Paul Smith, Practical Action Publishing
• How to Make a Rolling Machine for Sheet Metal Work – Workshop Equipment 3
Rob Hitchings, Practical Action Publishing
• How to Make Cutting Shears for Sheet Metal – Workshop Equipment 4
Rob Hutchings, Practical Action Publishing
• How to Make a Hand-operated Holepunch – Workshop Equipment 7
Ted Stone and Jim Tanburn, Practical Action Publishing
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