Wobbly upper rudder shaft bushing - Solved

[P69]

The diameter of the hole in the big chunk of 2" wood which supports the upper end of the rudder shaft is about 1/2" too large and the rudder shaft wobbles. The cheap, plastic bushing is in place, but I guess the Pearson folks didn't have the correct size hole saw on the day they made this piece.

To stop the wobbling and not rip out/rebuild the entire support, I made a bracket that bolts to the underside of the athwartship 2" x 8" board. I might have been able to find a bushing that might fill the hole properly, but the bolts holding the quadrant together are pretty tight and didn't want to risk breaking them (stainless steel bolts in an aluminum quadrant, probably seized after 30 years). I figured it would take less time to build the bracket in a weekend than risk breaking the bolts trying to remove the quadrant.

I thought of using a pillow block, but there is no way to get it on without removing the quadrant and 2" x 8"  cross beam, so I made my own.

It's kinda rough looking because I haven't givne it the final clean-up and acid bath to make it look shiny and pretty.

Picutures:  
http://s1278.photobucket.com/user/scherzoja/library/Rudder%20Shaft%20Bracket


It's made of of 3/16" pipe that I split down its length (and removed aobut 3/8" of the circumference on two opposite sides for form a round clamp. I welded 3/16" pieces of flat bar to the sides for the clamping bolts  and 3/16" plate to the to for through bolting to the 2x8.

The dotted line in the diagram is a weld joint. I couldn't cut an oblong hole, so I ground out two U-shaped holes in the two parts. When welded together, the oblong hole was formed.

Needed oblong hole so that plates can move when the clamp bolts are tightened.

The pictures show the prototype without the additional flanges for the through bolts/oblong holes.  It wasn't until after I attempted to install that I realized the holes are too close to the clamping bolts to get the through bolt up through the 2 x 8 cross piece.  I added the additional flanges, but didn't take any pictures.

1/16" thick teflon sheet lines the inside surface
The teflon is cut long enough to that the clamp bolts hold it in place.  0.06" teflon seems kinda stiff, but with moderate force it bent into shape.


--- Parts used --
Stainless Seamless Tube T316/316L
2" x 0.188" x 1.624"
http://www.onlinemetals.com/merchant.cfm?pid=14904&step=4&showunits=inches&id=902&top_cat=0
I bought a foot, used 3"
This piece of pipe had the perfect 1.5" dia when lined with .06 thick teflon sheet


teflon sheet (.06" thick)
http://www.onlinemetals.com/merchant.cfm?pid=15358&step=4&showunits=inches&id=223&top_cat=181

3/16" thick scrap 316 Stainless Steel flat bar I had lying arounh.



All bolts are 3/8" thick. Because there is not much torque on the clamp bolts, 1/4 or 5/16" bolts might have been usable. I used 3/8" because, during welding, I needed to bolt the pieces together really tightly  to prevent distortion and I didn't think 5/16" would do without stripping threads. It always amazes me how well heat/cooling metal can distort really thick metal. I also wanted to use the same bolt dia. for all bolts so I would only need one set of wrenches to manage this fitting (9/16" wrench/socket).

Four nuts on clamp bolts should be aircraft nuts because there is not enough torque to use lock washers. You can also use double-nuts, but aircraft nuts are easier.

Four nuts and lock washers bolt the bracket to the 2 x 8" cross piece.

I welded the clamp bolts to the bracket, but in retrospect, that was not a good idea because it complicates replacing the teflon lining.  With welded bolts, I have to remove it from the  2 x 8. If the bolts are not welded, I just remove those four, insert new teflon, insert the bolts, and tighten it up.

If the teflon ever wears out, I just loosen the bolts holding the