Date:         Fri, 16 Jan 2004 08:51:00 EST
Reply-To:     THX0001@AOL.COM
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         George Goff <THX0001@AOL.COM>
Subject:      Re: Exhaust stud drill out procedure
Comments: To: sam.cooks@VERIZON.NET
Content-Type: text/plain; charset="US-ASCII"

In a message dated 1/16/04 8:13:47 AM, sam.cooks@VERIZON.NET writes:

<< So what is the trick to insure that your drill is going straight into

the block.  I saw something at Home Depot . . .  >>

Sam,

I have no idea what you saw at Home Depot, but, over the years I have seen
all manner of useless drilling gizmo's.  To accurately drill a hole for an
insert with the engine in place you need a drill plate to help guide the drill on a
path perpendicular to the flange face of the head.  The drill plate I use is
simply a piece of 1" thick stock with 2 holes in it which are centered EXACTLY
the same distance as the stud tappings on the exhaust flange face of the
head.  One hole is sized to be a close fit on an 8mm stud while the other is sized
to fit the drill necessary for the insert.  Once centered on the hole to be
drilled, my drill plate is clamped in place by the remaining good stud.

I've also made bushings to fit the drill plate which are sized for drilling a
pilot hole and to drill out an 8mm stud.  If a broken stud has to be drilled
out, the surface of the break has to be smoothed then centerpunched right on
the nuts before any drilling is begun.  For that, I made a centerpunch to fit
the diameter of the insert drilling hole of the drill plate.  Before I made the
dedicated centerpunch, I would carefully first prick punch the stud by eye
with good results.

George