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Best way to drill a 2 5/16 hole adjacent to the breaker panel?

Mar 31, 2019
31
Catalina 22 12640 Avalon Steamboat Landing, Portland OR
Hi all,

I found myself with an unexpectedly free Sunday, so I decided to seize the moment and replace the POs poorly installed fuse panel with a Blue Sea Systems 8-position metal DC panel. (See this thread for photos of the old panel I was replacing.)

Besides having to cut a larger opening with a jig-saw in a slip with rolling conditions, the installation was smooth and straightforward. I forgot to take photos, but I'll post some next time I'm at the boat. I love that this new panel has a negative busbar built in.

I'm so thrilled with my new found electrical capabilities that I'd like to install a Blue Sea m-Series battery switch.

And here comes my question: Should I use the jig-saw to cut the 2 5/16th diameter circular hole for the battery switch, or should I use a drill with a hole saw attachment like this one? I'm planning on installing the switch adjacent to the original panel location (where my new panel now resides) just to port, and just forward of the companionway step. Apologies, I don't know what to call this part of the cabin. My concern with the hole saw is that it will either walk or chip the area I'm drilling and create a mess. The jig-saw went through that material like butter, but it's harder to cut round holes with a jig-saw, at least for someone with my limited skills.

Thanks as usual for any guidance!

Best,
Andre
 
Aug 9, 2011
1,046
Beneteau 310 Cheney KS (Wichita)
I would use the hole saw. To minimize the chipping on the surface, tape over the area that the saw will contact with masking tape. Then just go slow and don't apply a lot of pressure when you first get the saw blade in contact with the tape/surface.
 
Dec 28, 2015
557
Laser, Hunter H30 Standard Tacoma
Hole saw. Tape the whole area and press it down good. Go slow. The actual battery switch will more than likely cover any possible tear out from the process.
 
Jan 22, 2008
7,078
Beneteau 323 Annapolis MD
Drill the same hole in a piece of wood, with mounting screw holes that the switch needs. Screw the block to the fiberglass and use it for a hole saw guide. Taping the hole an okay idea, but some folks would do a quick shot with the drill in reverse to break through the gel coat. That said, I wonder why a switch ???
 
Jan 18, 2016
488
Catalina 30 Dana Point
Did anybody say hole saw? It's simple -- hole saw, drill thru, mount switch, drink frosty beverage.

2 5/16 (close enuf to 2 3/8) is too tight for a jig saw. Hole saw it should be. And it doesn't matter if it's in a rolly anchorage - once the pilot is set it's a done deal.
 
Oct 19, 2017
5,059
O'Day 19 Littleton, NH
If there's already a hole and you're just making it bigger, Ron's advice is perfect. If there is no hole and a pilot bit has a purchase. Rpludwig's suggestion should be all you need.

-Will (Dragonfly)
 
Jul 7, 2004
5,922
Hunter 30T Cheney, KS
My concern with the hole saw is that it will either walk or chip the area I'm drilling and create a mess. The jig-saw went through that material like butter, but it's harder to cut round holes with a jig-saw, at least for someone with my limited skills.

Thanks as usual for any guidance!

Best,
Andre
The hole saw will have a pilot bit. Slim to no chance of "walking" if you take it slow. I never free-hand a cut if there's a bit or blade shaped for the needed cut.
 
Sep 24, 2018
510
O'Day 25 Waukegan
Drill the same hole in a piece of wood, with mounting screw holes that the switch needs. Screw the block to the fiberglass and use it for a hole saw guide. Taping the hole an okay idea, but some folks would do a quick shot with the drill in reverse to break through the gel coat. That said, I wonder why a switch ???
x2
 
Apr 11, 2017
433
Catalina C22 Solomon's Island, MD
Drill the same hole in a piece of wood, with mounting screw holes that the switch needs. Screw the block to the fiberglass and use it for a hole saw guide. Taping the hole an okay idea, but some folks would do a quick shot with the drill in reverse to break through the gel coat. That said, I wonder why a switch ???
Like also stated here - whenever I'm drilling through fiberglass - I generally run the bit, or hole saw, in reverse a bit, to score the gelcoat. I think it helps some with a clean cut.
 
Feb 8, 2014
1,093
Columbia 36 Muskegon
If you can't find the exact right size hole saw you can cut it with the next smaller size, then open it up with a sanding drum on a drill. Dusty but easier than trying to cut and exact circle with a jig saw. That ain't easy.
 
Mar 31, 2019
31
Catalina 22 12640 Avalon Steamboat Landing, Portland OR
Awesome, thanks everyone for the feedback. I'm picking up a hole saw & arbor at Home Depot this afternoon, then heading to the boat this evening to drill the hole, using the tape suggestion to minimize chipping.

As to why I'm installing a battery switch, the breaker panel I installed has backlights that, without a battery switch, would be a parasitic draw on the battery. And, I just like the knowledge that there's an obvious and complete disconnect of the circuit when I'm not at the boat.

I'll post photos of the installed switch later, assuming all goes successfully.
 
Jul 7, 2004
5,922
Hunter 30T Cheney, KS
Make sure you aren't killing the always-on power to the bilge pump with this switch.
 
Oct 19, 2017
5,059
O'Day 19 Littleton, NH
If you can get to the back and the front of the part you're drilling the hole in, the best way to avoid chip out is to drill partway through on the front (3/4 of the way), then finish it on the back side. This also gives you a smaller bite on the waste plug for clearing it out of the hole saw after, because the plug won't get buried completely inside the bit.

-Will (Dragonfly)
 
Mar 31, 2019
31
Catalina 22 12640 Avalon Steamboat Landing, Portland OR
If you can get to the back and the front of the part you're drilling the hole in, the best way to avoid chip out is to drill partway through on the front (3/4 of the way), then finish it on the back side. This also gives you a smaller bite on the waste plug for clearing it out of the hole saw after, because the plug won't get buried completely inside the bit.
That is a great idea - I do have access to the back of where I'm drilling. I'll give that a shot.
 
Mar 31, 2019
31
Catalina 22 12640 Avalon Steamboat Landing, Portland OR
Success! Tape + hole saw was the winner. It was super easy, and not the slightest of chip.

The PO made a mess of the area around the panel, but I'm happy to say my new panel and switch are installed. Now to fill in the holes from the old panel, and re-coat whatever the hell is going on in the corner between the switch and the panel.

IMG_0019.jpg
 
Aug 10, 2014
310
Catalina 22 9874 Newberg, OR / Olympia, WA
A good reminder, but our boats don't typically have bilge pumps, so I'll be good there.
FWIW: I have three things wired always-on, separate from my master switch: Bilge pumps, solar controller, and battery monitor.

And after the master switch, but without any other switches: CO Detector and Fuel Vapor Detector. Whenever we're on the boat or out cruising, the master switch is on, so those are live - when we're away from the boat, we sometimes kill the master, but then we don't care so much about gases (and wouldn't be there to hear the alarms anyway).