Drilling a 2" hole over a 1" hole

Drilling a 2" hole over a 1" hole

Post by Randall Roorba » Tue, 22 Nov 1994 09:47:13


: How can I drill this so that the new hole will be centered where it needs
: to be and the drill bit won't wander off into the old 1" hole.  This is,
: of course, on the transom so I can't use a drill press.

I would try a hole saw bit and hold it carefully.  The best way, though,
would be to buy a Forstner bit.  They are round cutters that guide
themselves from the outside of the cut rather than with a center guide
bit.  They work incredibly well.  You can get them at good woodworking
stores and catalogs. Try the Highland Hardware Catalog--they are in
Atlanta, GA, get their 800 number from the 800 information operator.

Good luck, Randy in CT

 
 
 

Drilling a 2" hole over a 1" hole

Post by Joseph G. McWillia » Tue, 22 Nov 1994 01:00:18

I am replacing my 1"***pit drain with a 2" drain.  I need to drill a 2"
hole so that the bottom of the 2" hole corresponds to the bottom of the
existing 1" hole.  In other words, the center of the 2" hole will be the
top edge of the 1" hole.

How can I drill this so that the new hole will be centered where it needs
to be and the drill bit won't wander off into the old 1" hole.  This is,
of course, on the transom so I can't use a drill press.

--
Joseph McWilliams                Clothes make the man.  *** people have
Nacogdoches, TX                  little or no influence on society.


 
 
 

Drilling a 2" hole over a 1" hole

Post by abobo.. » Tue, 22 Nov 1994 11:53:45

Clamp,***or otherwise fasten a piece of s***wood
behind the existing hole.  Then use a holesaw with the pilot bit
in the wood scrap.  Before the s***is attached, use a file to
notch the transom where the pilot bit will go.

The saw may try to walk a bit if the new cut intersects the existing
hole.  This effect might be minimized by cutting around instead of
through the existing hole, and by using something more substantial
(e.g., thicker or harder (e.g., metal)) to keep the pilot bit
from straying.



 
 
 

Drilling a 2" hole over a 1" hole

Post by T R Frillm » Tue, 22 Nov 1994 11:57:19


: I am replacing my 1"***pit drain with a 2" drain.  I need to drill a 2"
: hole so that the bottom of the 2" hole corresponds to the bottom of the
: existing 1" hole.  In other words, the center of the 2" hole will be the
: top edge of the 1" hole.

: How can I drill this so that the new hole will be centered where it needs
: to be and the drill bit won't wander off into the old 1" hole.  This is,
: of course, on the transom so I can't use a drill press.

: --
: Joseph McWilliams                Clothes make the man.  *** people have
: Nacogdoches, TX                  little or no influence on society.

Easy***a block to one side that is larger than the new hole but the
screws are driven into the waste (that area to be removed by the new
hole).  Mark the new center on the screwed on block and cut your new hole
with any hole saw with a long center pilot bit.

Tom

--

 
 
 

Drilling a 2" hole over a 1" hole

Post by Michael B. Lain » Tue, 22 Nov 1994 18:21:12

On 20 Nov 94 16:00:18 CST,

Quote:
>I am replacing my 1"***pit drain with a 2" drain.  I need to drill a 2"
>hole so that the bottom of the 2" hole corresponds to the bottom of the
>existing 1" hole.  In other words, the center of the 2" hole will be the
>top edge of the 1" hole.

>How can I drill this so that the new hole will be centered where it needs
>to be and the drill bit won't wander off into the old 1" hole.  This is,
>of course, on the transom so I can't use a drill press.

When I needed to drill out my through-hulls I found some dowling (or a
tapered plug would work fine) just slightly larger then then hole.  Then
sanded it till it could just be driven in and stick tight.  Then drilled
like there was no hole there at all.

Mike Laing

 
 
 

Drilling a 2" hole over a 1" hole

Post by Bob Kur » Tue, 22 Nov 1994 23:38:33


Quote:

> : How can I drill this so that the new hole will be centered where it needs
> : to be and the drill bit won't wander off into the old 1" hole.  This is,
> : of course, on the transom so I can't use a drill press.

> I would try a hole saw bit and hold it carefully.  The best way, though,
> would be to buy a Forstner bit.  They are round cutters that guide
> themselves from the outside of the cut rather than with a center guide
> bit.  They work incredibly well.  You can get them at good woodworking
> stores and catalogs. Try the Highland Hardware Catalog--they are in
> Atlanta, GA, get their 800 number from the 800 information operator.

You might also try plugging the 1" hole with 1" dowel stock.  Then use a 2"
hole saw, and the wood dowel will support the center pilot bit very well.
This way you won't wander all over the transom and make an embarassing
mess.

Note - always measure 3 times before drilling near the waterline!

 
 
 

Drilling a 2" hole over a 1" hole

Post by Steve Weinga » Tue, 22 Nov 1994 22:29:25


Quote:
>Subject: Drilling a 2" hole over a 1" hole

>Date: 20 Nov 94 16:00:18 CST
>I am replacing my 1"***pit drain with a 2" drain.  I need to drill a 2"
>hole so that the bottom of the 2" hole corresponds to the bottom of the
>existing 1" hole.  In other words, the center of the 2" hole will be the
>top edge of the 1" hole.
>How can I drill this so that the new hole will be centered where it needs
>to be and the drill bit won't wander off into the old 1" hole.  This is,
>of course, on the transom so I can't use a drill press.

Get a piece of dowel (or cut a plug with a hole saw), and glue it in the hole,
then just use a hole saw of the right size. Buy it from Home Depot or the
like, it cost me $4 for one for my new waste line; 'marine' would've been $20.
 
 
 

Drilling a 2" hole over a 1" hole

Post by Paul Osbor » Wed, 23 Nov 1994 01:37:14



Quote:
>I am replacing my 1"***pit drain with a 2" drain.  I need to drill a 2"
>hole so that the bottom of the 2" hole corresponds to the bottom of the
>existing 1" hole.  In other words, the center of the 2" hole will be the
>top edge of the 1" hole.

>How can I drill this so that the new hole will be centered where it needs
>to be and the drill bit won't wander off into the old 1" hole.  This is,
>of course, on the transom so I can't use a drill press.

        Joe, I have used two methods with good results.
        Fill the old hole or place and some how wedge a backing
        board behind the place that you want to drill. I asume that
        you are using a hole saw and need something for the pilot
        drill to go onto.

        paul

 
 
 

Drilling a 2" hole over a 1" hole

Post by Tom Lei » Wed, 23 Nov 1994 00:33:17

: How can I drill this so that the new hole will be centered where it needs
: to be and the drill bit won't wander off into the old 1" hole.  This is,
: of course, on the transom so I can't use a drill press.

Assuming your transom is "thin" (ie: not made of wood), I would back the
area around the existing hole with a piece of wood to stiffen the area
while the hole-saw or Forstner bit mentioned by previous posters did their
jobs.  The backing can be clamped or even glued in place while you do your
thing.  If you use glue, keep the surface-area with glue on it to a
minimum so its easier to remove when you're through.

If you transom is "thick" (made of wood) I think I'd try the same basic
technique, but I'd make a "plug" for the existing hole and let the tool
remove it while cutting the new hole.  The plug is attached to the backing
piece, inserted into the hole, and then the whole mess is clamped or
screwed in place (from the inside, with short screws that won't go through
the transom).

Good luck, and be careful.

        t

 
 
 

Drilling a 2" hole over a 1" hole

Post by BRENT W. BENS » Wed, 23 Nov 1994 00:27:42


Quote:
eph G. McWilliams) writes:
>I am replacing my 1"***pit drain with a 2" drain.  I need to drill a 2"
>hole so that the bottom of the 2" hole corresponds to the bottom of the
>existing 1" hole.  In other words, the center of the 2" hole will be the
>top edge of the 1" hole.

>How can I drill this so that the new hole will be centered where it needs
>to be and the drill bit won't wander off into the old 1" hole.  This is,
>of course, on the transom so I can't use a drill press.

The usual method is to fit a 1 inch plug of similar material in the existing
hole. Then drill the 2 inch hole.  A hole saw works well as does a
forestner bit (wood only).

Brent Benson

 
 
 

Drilling a 2" hole over a 1" hole

Post by Rod Mc Inn » Wed, 23 Nov 1994 02:31:13

Quote:

>Clamp,***or otherwise fasten a piece of s***wood
>behind the existing hole.  Then use a holesaw with the pilot bit
>in the wood scrap.  Before the s***is attached, use a file to
>notch the transom where the pilot bit will go.

>The saw may try to walk a bit if the new cut intersects the existing
>hole.  This effect might be minimized by cutting around instead of
>through the existing hole, and by using something more substantial
>(e.g., thicker or harder (e.g., metal)) to keep the pilot bit
>from straying.



  This approach will work fine, if you can make the attachment.
Otherwise, try filling the hole.  If the existing hole is one inch, use
a one inch hole saw an make a plug.  Glue or epoxy this plug into the
existing hole, then use a two inch holesaw to cut the larger hole.

  Either way, the approach is the same.  You need to provide a center
for the guide drill.  There is no way you would ever be able to hold a
drill steady enough to drill without it.

        Rod McInnis