Description

Wedge Holding Block

Purpose Of Wedge holding block

1) The wedge holding block, being firmly attached to the strut, provides the means for holding the corresponding wedge that makes up the forward part of the stationary cutter.

2) When a line is caught between the stationary cutting blade and the rotating cutting blade (attached to shall), the wedge forces the two blades tightly together, overcoming the resistance of the bearing and instantly cuts the line. Normally the stationary and rotating blades never touch; they are held apart by the teflon bearing which purposely isolates the metals from wear.

3) At the instant of cut, the blades come closer together.

Examples Of Wedge holding block

Mounting The Wedge holding block

1) The wedge holding block is mounted onto the the stem bearing tube or strut and held by stainless steel screws (provided with cutter). Holes are to be drilled and tapped to receive these screws. Holding block is to be used as a template in place when all but first screw is drilled and tapped.

2) The wedge holding block is to be mounted on the same side of the strut as the rotation of the propeller.

Example: If there is a right-hand prop, the holding block would be mounted on the starboard side of the strut; on a left-hand prop, it would be mounted on the portside of the strut.

3) Holding block must be positioned to accommodate the stationary cutter wedge, with the stationary cutter wedge entering only one-half way into the V of the holding block. This is important to assure enough clearance to move with shaft and avoid bottoming in holding block V. If the male wedge of the stationary cutter touches the bottom of the female wedge holding block during forward end play, this will force the cutter blades together grinding metal on metal, causing the blades to be destroyed through excess friction.

How To Select The Wedge Holding Block To Fit Your Cutter

1) The Holding Block (mounted on strut or stem tube) relates to cutter mold type.

2) Using the cutter mold type, refer to Fig.1 for overall cutter length.

3) Subtract the vessel’s strut outside diameter from overall cutter length. Then / 2 = Holding Block Height.

 

MOLD TYPE	OVERALL LENGTH	MOLD TYPE	OVERALL LENGTH
A	4″	F	10′
B	5″	F1	11′
C	6″	F2	13 1/2″
D	6 3/4″	F3	15 3/4″
E	7 5/8″

Fig.1 Diagram and Table on Cutter Lengths

4) Using the height figure, select holding block from chart Fig.3.

 

5) Formula To Determine Holding Block:
(as seen in Fig.2)
Cutter overall length
Subtract strut diameter
Divide by 2

After the holding block height has been determined, it is an easy matter to choose the holding block mold type from the chart Fig.3. Match the height needed to the closest height of holding block available. Use shims if needed!

WEDGE HOLDING BLOCK SIZES AVAILABLE
MOLD TYPE	HEIGHT	CLEARANCE HEIGHT	WIDTH	LENGTH
#AA	.900″	1/8″	1 1/4″	3″
#1	1 1/8″	5/16″	1 3/8″	3 1/4″
#2	1 1/4″	1/2″	1 5/8″	3 1/2″
#3	1 1/2″	1/2″	1 3/4″	3 5/8″
#3A	2″	7/8″	1 3/4″	3 11/16″
#4	2 1/8″	9/16″	2 1/4″	4 5/8″
#5	2 1/2″	3/4″	2 3/4″	5 1/2″
#5A	3 1/8″	3/4″	2 3/4″	5 1/3″

 

Fig.3 Wedge Holding Blocks Table and Diagram

The above are actual diagrams of the wedge holding blocks that are available. In most cases, they are interchangeable with cutters of different mold types. They are selected for the best height match to secure the wedge portion of the stationary cutter.

Shims

Shims are available to raise the holding block to attain a height fit (when needed). Position shim under holding block then drill and tap into place.

Wedge Holding Block No. A, AA, 1, 2, 2A, 2B, 3, 3A, 4, 5, 5A

Shim No. 1, 2

Stationary Fastening A-E, F-F3

Driven Fastening A-E, F-F3

Holding Block Fastening 5/16”, 3/8”

Lock Washer

Bonding Wire: Small, Large