RECOIL GEARING FOR PUNT-GUNS 185 
and two wrought iron straps ‘‘shrunk ” around the barrel and 
holding ends of the loop. This may be noted by reference to 
our sketch. The iron straps are made small for their seats. 
By heating them to a bright blood-red they are expanded, and 
can be driven on. They are then cooled, and thus by contrac- 
tion secure a very tight grip on the barrel. 
We may add, for those who intend using a spring recoil 
gear, that our sketch is made from one which has proved of 
good service in years past, and is of safe dimensions and of 
original expert design. The width of the sliding block which 
lies in the double eye pivot is that of its vertical diameter. 
It is best to make this gear, except the springs, of wrought 
steel, but it may be made of similar metal as the barrel, 
and if this latter is not steel, some extra allowance made 
in thickness for proportionate strength. The back check 
spring should be lighter (i.e. of thinner wire) than the recoil 
spring, as shown. The guide inside the coils of the back 
check spring should nearly fill or fit. This guide, if too small 
in diameter, will allow the spring to ‘‘ side bulge.” 
The whole gear can be readily dismantled, which may be 
easily seen on reference to sketch. If by some unforeseen 
cause a spring should happen to break, an iron washer or ring 
of same size as the coils, placed between the broken parts, will 
set matters right until such time as a new spring can be 
procured and fitted. In fitting the springs the requisite 
amount of contraction is an important item. The correct 
length of the springs is also of importance, for, unless this, 
as well as the proper amount of contraction, is allowed for, 
the correct balance of the gun will be affected. These points 
are not of so great importance in the case of fitting a complete 
gear of this kind to an old gun, for then the point of balance 
can be ascertained experimentally, as when the loop is made 
with the gun, or new springs are being fitted which may be 
slightly longer, shorter, weaker, or stronger, for it is difficult 
