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848 viewsPitching blocks can be made of wood but metal last foreever.Jim Allen
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860 viewsThe pitching blocks use dowel pins for alignment. When the pitching blocks are closed in a vise, the propeller blades are held securely for pitching up or down. On the left are pitching blocks used to bend 2170 blades; in the middle V-967 blades; on the right are pitching block cavaties.Jim Allen
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1013 viewsThe material used in the pitiching blocks is West System #105 epoxy resin; #205 fast hardener; & a very large amount of #404 high density filler. The blades are covered with a thin film of grease to prevent the epoxy from sticking. Do one side at a time; then use a thin film of grease to prevent the second side from sticking.Jim Allen
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Propeller pitching blocks1084 viewsC-20 beryllium copper props are annealed & clamped in pitching blocks in a vise.The propeller blades can be easily twisted to the required pitch after inserting a hardened steel shaft through the hub. No type of modified plier is ever used to re-pitch propeller blades or add tip pitch!Jim Allen
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Progressive pitch anvils1134 viewsThese anvils are used to make different amounts of progressive pitch. They are held rigidly in a machinist vise & a dead blow rubber mallet is used on the back side of each blade. NO NICKS OR DINGS to be removed on the inside or outside of blade surfaces with this method! Jim Allen
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1274 viewsThis is a Kalfus type pitch gage. It reads pitches directly with removable plates in 1/8 inch steps; five different pitch plates can be mounted at one time. The idea for this pitch gage is taken from the Machinery's Handbook; 21 edition; page 1480 (helical milling). The gage has plates to enable pitching from 3 to 11 inches. This very accurate pitch gage is easy to use & it can mount a Starrett .0005 in dial indicator for making blades identical.Jim Allen
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A very sensitive magnetic balancer1749 viewsThis magnetic prop balancer can be leveled with three set screws accessible from the top of the balancer. A hardened precision ground CONCENTRIC shaft makes this device very sensitive. Once the blades are balanced, very slight polishing with 800 grit paper throws the balance off! Notice the round leveling device under the propeller. IF A PROPELLER BLADE ALWAYS BALANCES IN THE SAME HORIZONTAL POSITION, IT IS OUT OF BALANCE! EVERYTHING BELOW THE CENTER LINE NEEDS TO HAVE ITS WEIGHT REDUCED! THIS COULD BE THE LEADING EDGE OF ONE BLADE & THE TRAILING EDGE OF THE OPPOSITE BLADE FOR TWO BLADED PROPELLERS! THE SAME PRINCIPLE APPLIES TO MULTI BLADED PROPS.Jim Allen
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856 viewsC-20 beryllium copper (copper alloy C82500) blades are hardened in a heat treating oven. Props are held at 650 deg. F (+- 5 deg F) for 2.5 to 3 hrs. The time in the oven is not critical, but the temperature is to achieve the ultimate tensile & yield strength. The tensile strength should be 160,000 psi with a rockwell hardness of 45. These blades will not bend & cannot be repitched without annealing.Jim Allen
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917 viewsAll these propellers have been hardened after annealing to allow pitching. Anneal C-20 beryllium copper by heating to 1450 deg. F (dull red) in a dark room. Quench immediately in ice cold water. If the props are heated to hot during annealing, the beryllium will leach out & the blades connot be hardened. I re-anneal finished balanced pitched props to ensure stabilization before hardening.Jim Allen
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857 viewsThis silicone rubber mold is used to make wax castings for the lost wax process in making cast propellers. When casting C-20 beryllium copper use a dedicated melting pot that has not been used for any other alloy. If the melting pot is contaminated, the beryllium copper blades that are cast will distort when heat treated.Jim Allen
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