ALLMAND 31 RUDDER THRUST BEARING (BUSHING).

 

This writeup goes along with the Thrust Bearing (bushing) drawing.

 

Please Note:: All Dimensions Were Taken From The Reassembled Broken Bushing Off My Boat and may be different for your boat, I suggest that you carefully measure you bushing

 

How & What I did.

 

Get hold of a hunk of material at least 3.25 X 4.25 X 5 inches. I used a Nylon because thats what I had, I dont reccomend it because it is very hard to machine, it tends to melt while cutting, so find some other material like delrin or hard neopren which is easy to machine. I believe the original bushing was made of a graphite& epoxy mould.

 

1 Machine the thickness TOP to Bottom--from drawing, these surfaces must be parallel. mine measured 3 3/16 inches.

 

2 Slice the piece to create the front and back sections, on mine the back was exactly 2 inches and the front was 2 11/16 inches.  Once cut use double stick tape to glue these two pieces together, then use a clamp to make sure they stay together.

 

3 Locate the center point of the 1 1/2 Inch hole that must be drilled thru the chunk, Center the hole on the seam of the front & Back pieces equal distances from each side. Once done use a forstner bit and drill the hole, remember to put a piece of wood under the chunk of material. Do Not Seperate The Pieces until the bushing is finished.

 

4 Once the hole is drilled, use the pattern to trace the outline of the bushing onto the material, make sure the hole in the pattern lines up with the hole in the material, and cut the material to shape using a Band Saw.

 

5 Cutting the shoulders and the dado. Note that on the drawing I show 2 Wood Shims, these are needed to create the taper in the shoulder and the dado, the shims should be attached with double stick tape and left attached till finished.  I did my cutting on my table saw using two fences as follows. I set my fence 1/2 inch from the blade and set the blade height to 5/16 inch. then I placed the Top of the bushing against the fence, and added the second fence up against the bottom of the bushing, this kept it from moving sideways.

 

WARNING--Be very careful when cutting the dado ,the saw may try to throw the bushing across the room or at you get a good grip and be careful.

 

Then I turned the saw on and proceded to slide the bushing front to back and rolling it over about half way thru so that I cut the shoulder all around and the taper came out properly, now lift the bushing out

and turn it around and do the other side. Now move the fence about one blade width away from the blade, put the bushing back against the fence and put the second fence against the bushing, start cutting the dado, it takes a while but it works.

 

6 Whe finished with the dado remove the shims and with a rasp smooth out the dado.

 

7 Test fit, I found that I had to round the the top of the back section to make it fit properly and then I had to use the rasp to open the hole slightly. I installed it and it works.

 

8 I did not remove the rudder and I had to bend the U bracket slightly to get it back in.

 

Please email me at gilligan@hvc.rr.com with any questions…..

Dan.