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Construction Notes |
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Shoulder Slats |
| The
formers for the three sizes of slats were made
up from CDX ply and MDF, profiled and finished
in P40 filler which was sanded to a fine finish
before being given a coat of G4 sealer. |
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A coat of
PVA release agent was applied, and the process
of laying up the moulds (as described for
previous sections) was undertaken. A thickness
of 1/8" was built up due to the small size of
the moulds. |
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The casts
were made using black gelcoat, tissue and coarse
mat, and this was trimmed to the back edge of
the mould just before the cast had 'cured',
otherwise it would have been a case of 'get the
grinder out'. |
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| After
laying up all the casts, it was noticed that the
bolt recesses were a little weak, so an extra
couple of layers of coarse mat were added inside
to improve strength, prior to drilling for the
M4 bolts. |
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| Due to
the way the shoulder and upper collar profiles
curve, each slat had to be individually profiled
to fit its position on the shoulder. |
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Arm
Box 'bearing' |
| These
were made up from 18mm and 12mm CDX ply,
profiled and made up to form a 'bearing' for a
100mm HDPE sphere. Four M4 bolts with springs
and wing nuts were used to provide tension
adjustment of the arms when in place. |
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| These
units were eventually bolted and glued to the
inside of the shoulder unit. |
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| The
front bearing plate (glued to the inside of the
shoulder) is fitted with four captive nuts, and
these are used to hold the outer plate, and
therefore the arm itself, in place in the
'bearing'. |
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|
Arm
Box Face plate |
| The
former was made up from 2 layers of 3mm MDF,
filed and sanded to shape and glued together to
form the completed item. A fibreglass mould was
taken and casts were made from reinforced black
resin. |
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| These
front plates are held in place with four 30mm
socket button screws. - It is these front plates
that actually hold the arms in place, and can be
removed for easier storage of the arms when not
in use. |
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arm
bearing in place in the shoulder |
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Go to Part
7 - gun arm &
plunger |
