Making an existing 3/4 inch hole into a 1 inch hole in my boat

[snookonfly]

What’s the best way to accomplish this without destroying the gel coat around the hole?

Hole saw? Step bit? Sand drum?

Let me hear your ideas!

[bassinloose]

I would look into a fine reamer bit

[21XDC]

Plug the hole with a 3/4 in dowel and re drill? Step bit shoulkd also work...

[BoatNoobie]

3/4" hole saw inside a 1" hole saw

Or just use the 1" hole saw and start backwards slowly.

[CatFan]

Cut a 3” long plug of wood out of a piece of 2 by or 4 by lumber with a 3/4” hole saw. Put the plug on the drill bit of the 1” hole saw so half is past the teeth. The plug will center the 1” hole saw wile you cut.

[pflat]

Plug the hole with a 3/4 in dowel and re drill? Step bit shoulkd also work...

^^^^^ This… Glue the dowel in if you have to… Then tape the area real good with masking tape and use the finest hole saw you can find and run it through in reverse.. Then chamfer the new hole with a stone.. You can get one that with go in a drill chuck..

[Tinny]

Here's a trick to do it with a hole saw. Profanity warning.

[RazorCat]

3/4" hole saw inside a 1" hole saw Just like the video. Used that trick many times.

[PolarKraft195]

Here's a trick to do it with a hole saw. Profanity warning.

^^^THAT^^^

[Drothgeb]

A good step bit cuts a cleaner hole.

[LTZ25]

Drimel tool would work fine , just mark a circle first .

[bassboat1]

I usually clamp a piece of 1/2" plywood, with the larger hole in it for reboring doors, etc...

[PSM207]

Uni-Bit "stepped bit"