Preview: Drilling Holes with Boring Bars
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July 26, 2012
Email this Video to a FriendHave you ever wondered how they bore a 10+ ft straight hole through a hull? Let’s take a trip to a few boatyards and let the the pros show you how it’s done.
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5 Responses So Far to “Drilling Holes with Boring Bars”
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Robert Gordon says:
video explains the obvious, but not the trick of boring the initial hole prior to the boring bar.
Ken Page says:
When boring the off center shaft hole for the Schooner MARY HARRIGAN ( so many moons ago) I set up a, 3′ long 1/2-13 threaded rod beyond and past the end of the boring bar which I drilled a center drill hole in the end. With the threaded rod sharpened to fit in the center-drilled hole, a helper could un-screw the threaded rod to feed in or out and supply me with an even feed and speed for the cutting tool as I handled the drill maintaining pressure towards the threaded rod. The last 1/16″ of bronze on the stuffing box, strut, pintels and gudgeons were finish bored in this manner after they were finish mounted to the hull etc.
Jerry Rose says:
Wow I wish I had known this technique years ago when I used large barefoot augers with a hope and a prayer that you were boring the hole in the right place.
Doug Hylan says:
The initial pilot hole usually requires a bit of guess work. It must be at least as big as your initial boring bar diameter and hopefully accurate enough so that the final hole will clean up any inaccuracies in the pilot hole. Sometimes a tiny hole can be drilled in the estimated location and a string pulled between the known centers to get a more accurate location for the pilot hole.
Sometimes two boring bars of different diameters can help — a small pilot hole can be accurately enlarged with a small boring bar in preparation for boring the final hole with a larger diameter, more rigid bar. The more rigid the bar, the smoother and more accurate the hole.
Each job is different, and some ingenuity is often required.
David Johnson says:
I understand the principle of the boring bar but what I would like to see is the initial pilot hole being drilled and a discussion of drill sizes.