322 Improvement on the Axis of large Water-Wheels. 
The wood shaft of a water-wheel, 18 feet diameter, was se 
worn and decayed at one end, by frequent putting in and wedging 
.of the gudgeon, as to render a repetition of that process im- 
practicable. Robert Hughes, in this difficulty, contrived a cast- 
iron gudgeon, with a hoop to it, which inclosed the end of the 
shaft ; it was put on and fastened, and has worked steadily ever 
since. [am informed, that he puts the hoop gudgeon now ou 
new shafts, and it seems to me a great improvement upon the 
gudgeons formerly in use, E. 
Ruthin, Sept. 14, 1812. ; Joun JonEs. 
Reference to ihe Engraving of Mr. Ronerr Hueuss’s Method 
of fixing Pivots, or Gudgeons, into the Shaft or wooden Axis 
of a Water Wheel, which will prevent the Danger of their 
gelting loose in the Shaft, and permit their being repaired 
when damaged, Plate V. Fig. 1, 2,3. 
The ordinary method of fixing gudgeons into wooden shafts, is 
to have an iron cross, formed on the end of the gudgeon, which 
is let into the wood, to a considerable depth, and is held fast by 
small wedges, driven in round it, hoops being fitted round the 
outside of the shaft, to prevent the wedges splitting it. The 
defects of this method are, that the shaft is much weakened, by 
the cutting into it; and the constant strain of a heavy wheel, 
always acting in different directions, causes the wedges to be- 
come loose, and at length fall out ; the failure of the gudgeon is 
frequently attended with more serious damage, for the wheel 
falling upon the hottom of the race, generally breaks the mm and 
buckets by its own weight. 
The improvement made by Mr. Hughes, consists in applying 
a cast-iron box to the end of the shaft, and to this the iron cross 
of the gudgeon is screwed, so as to fasten it more firmly than by 
the old method, and without weakening the wood by cutting it 
away. AA, fig. 1, of Plate V. represents a portion of the end of 
the wooden shaft, which is of an octagonal form, and has the 
water-wheel-fixed upon it; it is long enough to reach across the 
pit, in which the wheel works, and having a gudgeon at each 
end, is supported and revolves upon them in proper bearings. 
BB is the cast-iron box, fitted fast upon the end of the shaft, 
and being wedged tight, preserves the wood from splitting as 
effectually as any hoops can do; upon the end of the box is a 
projecting flanch, aa, and in the face of this four grooves or 
notches are made, for the reception of the arms of the iron cross 
bb, dd, which is part of the gudgeon C, on which the shaft re- 
volves ; this cross is firmly attached to the box, by four screw 
bolts, which pass through the flanch, and also through the ends 
of the arms of the cross, having nuts screwed on the outside 2 
make 
