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craigdskilling
02-17-2010, 07:11 PM
Need some advice for drilling new 4'' holes where the 3'' are now.I think I need to fill in the old first so the hole saw has a new start.But with what.Also what do i use between, or in the new holes for the water sealing.
:bonk:

gcarter
02-17-2010, 07:30 PM
How about a piece of wood? It has to fit tight though until the saw really bites.

TXDONZI
02-17-2010, 08:54 PM
Put the 4" saw on 1st and then install the 3" saw on the inside of it. You will need an arbor that has long threads on it. Tape off the area with 2 layers blue painters tape in opposing directions. Start off very slow and with the drill in reverse until you break the gelcoat and glass. Come in from the backside just the same way if you have room. Stop take the 3" saw out of the 4" saw and continue in from the outside slow and easy keeping the hole as straight as possible. If the transom is thicker than the saws depth you will need to finsh from the inside.

gcarter
02-17-2010, 09:10 PM
Actually, the thick wood will come out in layers, just dig it out of your saw periodically.

realbold
02-17-2010, 09:43 PM
Also what do i use in the new holes for the water sealing.:bonk:
3 coats of unthickened epoxy or epoxy paint.

VetteLT193
02-18-2010, 10:28 AM
As already suggested do the inside half way, outside half way method. To make sure you are dead on drill a pilot hole in the center first. This way you can flip from in to out and be perfect.

MOP
02-18-2010, 04:22 PM
The easiest way is to cut a 3" blank out of 3/4" plywood, the take electrical tape and wind it around the outside until it is large enough to bang into the existing 3" hole. It will already have the pilot hole and will guide the saw with -0- sweat. Cut with little to no pressure slowly easing the saw in and out to to clear the teeth, the debris will fall out of the side slots!

*@*@*@ DON NOT TRY TO GO FROM THE INSIDE WHEN THE SAW BOTTOMS@*@*@

Simply as stated by George stop and break some of the material out of the hole and continue, most transoms are irregular on the inside the saw will jump and could jam and do damage. Do all your cutting from the outside in.

Phil

A= P.S. once you get a decent start into the glass knock the taped blank out to use in the other hole, it can be a pain getting out if left in the thin ring that you cut out!

gcarter
02-18-2010, 04:33 PM
If you have an older Classic, the thick part of the transom almost bisects the exhaust holes, so I don't see a way you could cut from the inside???????

Well, not me anyway!

MOP
02-18-2010, 04:39 PM
George over the years I bet I have re-cut several hundred holes in glass the tape blank is by far the best and easiest to get center and to start the saw.

LKSD
02-19-2010, 07:39 AM
George over the years I bet I have re-cut several hundred holes in glass the tape blank is by far the best and easiest to get center and to start the saw.

Yep, I agree a plug first makes life easier.. ;) J

NJFASTECH
02-21-2010, 07:00 AM
Put the 4" saw on 1st and then install the 3" saw on the inside of it. You will need an arbor that has long threads on it. Tape off the area with 2 layers blue painters tape in opposing directions. Start off very slow and with the drill in reverse until you break the gelcoat and glass. Come in from the backside just the same way if you have room. Stop take the 3" saw out of the 4" saw and continue in from the outside slow and easy keeping the hole as straight as possible. If the transom is thicker than the saws depth you will need to finsh from the inside.

I agree with you on this.If the hole just needs to be enlarged the 3" holesaw will act as a guide in the existing 3" hole while the 4" will remove an additional 1/2" at the same time.No pluggin required done in 20 Minutes or less:wink:

MOP
02-21-2010, 11:03 AM
Using one saw inside another does work but what I have happen in our shop was the inner saw bound when slightly cocked which being as it was on just a little bit of thread it ripped the first few threads of the arbor. I told my guys not to do it that way anymore period!

NJFASTECH
02-21-2010, 04:32 PM
Hole saws should not rely on thread alone at that diameter that is why a good quality arbor has a secondary locking system and that is why there is two holes outside of the threaded center for the secondary to fit into. Anything over 1 1/2" will have it.

MOP
02-21-2010, 05:25 PM
Hate to argue but all our tools were just cheap Snap On! The pin locks will not come through and hols the second drill!