Boring a hole to fit a stern tube assembly

[Iain_H]

Sorry about all the questions. One day I will repay this debt.

here's the challenge:

I have a stern tube that is one quarter inch wider than the hole it is designed to fit (its the closest match to this old fibreglass boat). The the length of the hole from the engine to the ouside world is a maximum of two feet, but i think it sapproximately one and a half feet in length.

So, I am going to bore the hole out an extra one quarter inch. The tube itself will stick out aft about nine inches when completed. this will be covered with foam and then glassed in.

Questions:

1. Best practice to bore out this hole in the boat ?

2. How precise should it be ?

 

[maxi]

To do this I did the following:

Made up a strong metal rod longer than the length of the sterntube, and cut a slot at one end. Welded in a piece of 'hard' metal the exact diameter of the new hole - careful to center it. This forms a cutter and should have nice sharp edges.
Turned up two wooden bearing rings that were just a fit in the original hole and fitted these onto the rod.
Put the rod through the hole from inside the boat, and attached a beefy electric drill to the blank end, and pull-drilled
using the wooden bearings to follow the alignment.
Took about 20 minutes of hard grunt, but the result was spot-on.
Good Luck

 

[oldsaltoz]

G'day Iain,

Have a look in your phone book fir 'line borers' and get some quotes; they will have the whole job done to perfection in under an hour and don't charge like wounded bulls because fibreglass has little effect on their cutters.

Andavagoodweekend.

 

[Iain_H]

ach just fannnnntttaaasstic guys.

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