Drilling larger bulkhead

mikeintosh · 06/19/2010, 12:07 AM

Are there any suggestions as to the proper way to drill a larger bulkhead hole over an existing one? My new pump requires 2" piping for input and the current hole is for a 1 1/2" bulkhead. The sump is acrylic.

I figured I would just trace the hole size I'd need (~3") and use a dremel to cut around. But it would probably end up looking rough and uneven. I was wondering if anyone has tried using a hole saw without material for that center bit to hold the saw in place? Would it work? Or would the drill just fly around? Don't want to lose a finger or put an eye out...

Suggestions please...

Thanks

THEUNION1 · 06/19/2010, 12:29 AM

Hole saw a hole in a piece of wood first then clamp piece of wood to panel over existing hole to be drilled. It will guide you without walking the hole saw.

mikeintosh · 06/19/2010, 03:03 PM

That's very clever. Thanks for the tip!

RokleM · 06/21/2010, 08:54 AM

THEUNION1 is right on. One thing to note however, you have to be a little more careful in ensuring the area stays clear of debris since the material can't easily "fling" out like normal. Perhaps get a helper with a shop vac to suction out material every 5-10 seconds as you drill through.

NoHooks · 06/21/2010, 10:33 AM

Another option is to install a second 1.5" bulkhead and connect both bulkheads to a 2" tee using 1.5" to - 2" adaptors on the ends of the tee.

ReeferChris · 06/21/2010, 01:23 PM

A way i heard of cutting out a bigger hole is two use two hole saws at the same time basically fit the smaller on (the same size as the hole you have) inside of the bigger hole saw (the size you need) and tighten them both up to the drill bit attachment thing. I forgot where i heard this, and i don't know if anybody has ever done it like this. but basically since the smaller hole saw is inside the bigger one then it is raised enough so that it fits inside the pre-existing hole. Has anybody ever done it like this?

mikeintosh · 06/21/2010, 01:34 PM

That sounds like a variation on the wood solution. Both very clever. Another solution I just thought of was super glueing a piece of scrap acrylic over the hole first, then drilling whatever size is needed.

When I get all my plumbing in to get started, I'll let you all know which route I went.

Thanks again.

06/19/2010, 12:07 AM	#1
mikeintosh Mikeintosh Join Date: Jun 2004 Location: Los Angeles Posts: 356	Drilling larger bulkhead Are there any suggestions as to the proper way to drill a larger bulkhead hole over an existing one? My new pump requires 2" piping for input and the current hole is for a 1 1/2" bulkhead. The sump is acrylic. I figured I would just trace the hole size I'd need (~3") and use a dremel to cut around. But it would probably end up looking rough and uneven. I was wondering if anyone has tried using a hole saw without material for that center bit to hold the saw in place? Would it work? Or would the drill just fly around? Don't want to lose a finger or put an eye out... Suggestions please... Thanks

06/21/2010, 08:54 AM	#4
RokleM Registered Member Join Date: Apr 2005 Location: Greenville, SC Posts: 9,687	THEUNION1 is right on. One thing to note however, you have to be a little more careful in ensuring the area stays clear of debris since the material can't easily "fling" out like normal. Perhaps get a helper with a shop vac to suction out material every 5-10 seconds as you drill through. __________________ -Eric-

06/21/2010, 10:33 AM	#5
NoHooks Registered Member Join Date: May 2009 Location: Manassas, Virginia Posts: 89	Another option is to install a second 1.5" bulkhead and connect both bulkheads to a 2" tee using 1.5" to - 2" adaptors on the ends of the tee. __________________ Some mornings it's just not worth chewing through the leather straps. Current Tank Info: The Blue Lagoon - 240 gallon mixed reef

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06/19/2010, 12:29 AM	#2
THEUNION1 Registered Member Join Date: Dec 2008 Location: ORANGE COUNTY, CA Posts: 928	Hole saw a hole in a piece of wood first then clamp piece of wood to panel over existing hole to be drilled. It will guide you without walking the hole saw.

06/19/2010, 03:03 PM	#3
mikeintosh Mikeintosh Join Date: Jun 2004 Location: Los Angeles Posts: 356	That's very clever. Thanks for the tip!

06/21/2010, 01:23 PM	#6
ReeferChris Registered Member Join Date: May 2009 Location: Miami, FL Posts: 184	A way i heard of cutting out a bigger hole is two use two hole saws at the same time basically fit the smaller on (the same size as the hole you have) inside of the bigger hole saw (the size you need) and tighten them both up to the drill bit attachment thing. I forgot where i heard this, and i don't know if anybody has ever done it like this. but basically since the smaller hole saw is inside the bigger one then it is raised enough so that it fits inside the pre-existing hole. Has anybody ever done it like this?

06/21/2010, 01:34 PM	#7
mikeintosh Mikeintosh Join Date: Jun 2004 Location: Los Angeles Posts: 356	That sounds like a variation on the wood solution. Both very clever. Another solution I just thought of was super glueing a piece of scrap acrylic over the hole first, then drilling whatever size is needed. When I get all my plumbing in to get started, I'll let you all know which route I went. Thanks again.