Prop Mod Process

Arrow Shark
2011 Propeller Modification Process

Following the introduction of our vastly expanded range of props, all factory modified, sharpened and balanced, we would like to explain the process employed to produce the props. We hope this will help you understand the steps involved, and it may also be of assistance if you wish to modify your own props.

Comparison: Stock & Modified Props

AS1770/2 Mod Prop	AS1770/2 Stock Prop

Tools Needed:

#1: Air Compressor	#2: Prop Pitch Gauge	#3: Prop Balancer
#4: Prop Cupping Equipment	#5: Air Angle Grinder	#6: Rubber Hammer (used to bend the prop tips)
#7: Metal Hammer (used to cup the prop)	#8: Flat File (used to reduce the prop diameter, to trim the prop leading edges, to modify the trailing edges, etc.)
#9: Round File (used to trim the face of the prop blades)	#10: Prop Holder (used to hold the prop firmly during modification)	#11: Flap Disc Sander (100 grit)
#12: Abrasive Unitized Disc	#13: Sand Paper (320 grit)	#14: Sand Paper (1000 grit)
#15: Polisher Disc	#16: Light Weight Oil	#17: Electric Grinder
#18 :Prop Cleaning Towel

The following steps illustrate how Arrow Shark modifies our range of props:


#1: Install the prop on the prop holder and use the 100 grit flap disc sander on the air angle grinder to remove molding flash from the stock prop.	#2: Install the prop on the table holder and file the prop face smooth with the round file. Make sure that the shape of the prop face is identical on all blades.

#3: Thin the back of the blade, and reshape the trailing edge with the flat file.	#4: Adjust the prop diameter to the required specification with the flat file, measuring carefully that all blades are the same shape and diameter.

#5: Trim the prop hub and drive dog slot with the flat file.	#6: Trim the trailing edge to the modified specification.

#7: Remove all scratches from the blades with careful use of the abrasive unitized disc.	#8: Check the balance of the prop at this stage, and file from the back surface of the heavier blade until all blades are balanced.

#9: Use 320 grit sand paper wrapped into a tube to smooth the deeper scratches off the blades.	#10: Use 800-1000 grit sand paper combined with light weight oil to perfectly trim the prop.

#11: Rest the prop’s round tip on the center of the steel ball of the prop cupping equipment and draw a line around the tip – use that as a guide to make sure that both prop blade tips are cupped identically.	#12: Use the metal hammer to gently tap the prop tip, and slowly move toward about 1/4 of the trailing edge.
Please note that we have four different diameter steel balls for our prop cupping equipment at sizes of 2mm, 2.5mm, 3mm, and 3.5mm. We try each of our props on all the balls and then test them on boats to determine which diameter ball produces the prop with the best performance. Where it further helps performance, we form a cup (or curved lip) in the trailing edge of the blades to give the prop an even better grip in the water. This results in reduced ventilation or slipping and often results in better acceleration from rest. Cupping can also be very beneficial when the prop shaft has been angled or trimmed so that the propeller is near the surface of the water; in such cases the cupping will typically result in higher top end speed.

#13: After completing the trailing edge cupping, move the hammer to slightly cup about 1/3 on the leading edge.	#14: Use the prop pitch gauge to check that each blade has identical pitch.

#15: Give the prop another balance check before polishing.	#16: Using the electric grinder polish the cup area on the prop face.

#17: Polish remaining area of the prop with the polishing disc on the angle grinder.	#18: Clean the complete prop so that it is ready to pack.
	#19: The modification is complete!

Following pictures show different angles of AS1770/2 Prop which has been done!

Click on the picture to enlarge