512 Forestry Quarterly 



The general construction is shown in the accompanying photo- 

 graphs, and a few of the details which may not be clearly evident 

 are described here for the benefit of anyone wishing to build a 

 similar machine. 



The model is 7 feet long by 18 inches wide and 40 inches high. 

 Each of its 10 compartments consists of a piston with the "trees" 

 fastened to the rectangular piston-head. This piston-head is 

 7x17 inches, of 1 inch soft pine and the "trees" are arranged 

 in 7 rows, 10 "trees" in 4 rows and 9 in 3 rows, making 67 "trees" 

 in all for each compartment. The "trees" are centrifuge brushes, 

 9 inches long over all, the brush part is 3 inches long, 1 inch di- 

 ameter at the bottom and ^ inch diameter at the top. The bristles 

 were stained green with Eastman's transparent photo colors. The 

 ring at the end of the handle was bent at right angles and fastened 

 to the piston-head by two staples. The piston rod is 2 inches 

 square by 12 inches long. The lower end bears directly on the 

 cam. In order to reduce friction here, the bearing parts were 

 smeared with soap and then oiled. 



The cams are made of % inch hard maple. The a:'nensions 

 are given in the sketch. The shaft \s oi Yz inch gas pipe and 

 has holes drilled at regular intervals to receive the pins which 

 fasten the collars in place. The collars are of J4, inch ha^-d 

 maple 1% inch diameter. Each cam is nailed to its collars in 

 such a position that its straight side is 36 degrees in advance of 

 its neighbor on the left. Thus each compartment is raised one- 

 tenth of its full height, higher than its neighbor on the right. 



We have demonstrated that the model will work nicely and 

 that it is worth developing into a neater and more finished form, 

 and are now planning a few improvements which are suggested 

 here. The wooden collars are to be replaced with metal and 

 keyed to a solid steel shaft. Instead of a direct crank attach- 

 ment to the shaft, a bicycle sprocket and chain will be used in 

 order to gear down the shaft revolutions, and bring the crank 

 to a more convenient height. The top of the model will be made 

 a few inches wider and instead of 3^ inch stuff, % inch cypress 

 will be used and the holes through which the "trees" appear made 

 \]4, inch instead of 1 inch. Underneath the piston-head a coil 

 spring will be used to reduce the jar when the compartment falls 

 after reaching maturity. The piston-rods will be made round 

 instead of square. 



