Or, as an alternative, you can go to Harbor Freight (and probably Lowes or Home Depot) and buy what is called a "Step Bit". It is a basically cone shaped drill with several steps which have a cutting edge for each larger diameter step. The 2-piece set I bought for a friends craft project has 23 steps from 3/16ths inch to 1 3/8ths inch, but Harbor Freight had options up to about 3" diameter.
The height of the step with the proper diameter might not be sufficient to go all the way through your hull, the core, and the inner skin. But it would certainly make a proper diameter depression in the hull of sufficient depth to fit the OD of your proper size hole saw... and the depression would be on the same hole center as the opening for your existing thru hull housing. Rick Brass Washington, NC -----Original Message----- From: Stus-List <cnc-list@cnc-list.com> Subject: Stus-List Re: Removing datamarine speed transducer C&C 29 mk2 The tricky part for me was caused by the newer sleeves being a size larger, so a friend gave me a tip. You find a holesaw the same size as the exiting hole and drill through some wood to make a pilot guide the same size as the hole you want to enlarge. Then you put the wood plug you made onto the pilot bit of the larger holesaw pilot bit, and it will keep the bigger holesaw centered and Bob's Your Uncle, you're all set. Good luck. Let us know how you make out. Chuck Scheaffer 1989 C&C 34R, Annapolis
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