Cutting 4" holes in fiberglass seat bases.

[trayson]

So I've found that cutting 4" holes with a hole saw is a serious PITA. My 18v cordless drills get toasted in short order. I even bought a corded drill and found that I can smoke the motor on that one before I make much progress on the hole. I've got a couple more hot tubes I can add to my heater system but drilling the holes is literally a process that takes multiple sessions of drilling over a day or days. It doesn't seem like it should be this hard.

http://hfreviews.com/thumbnails/38425.gif

What am I missing or doing wrong?

[sivs1]

So I've found that cutting 4" holes with a hole saw is a serious PITA. My 18v cordless drills get toasted in short order. I even bought a corded drill and found that I can smoke the motor on that one before I make much progress on the hole. I've got a couple more hot tubes I can add to my heater system but drilling the holes is literally a process that takes multiple sessions of drilling over a day or days. It doesn't seem like it should be this hard.

http://hfreviews.com/thumbnails/38425.gif

What am I missing or doing wrong?

First, your inbox is full, second, what are you trying to do with the seat bases? Are you meaning the walls between the bottom of the seat to the floor? I had no issues drilling holes through my LSV, just never went 4".

[trayson]

First, your inbox is full, second, what are you trying to do with the seat bases? Are you meaning the walls between the bottom of the seat to the floor? I had no issues drilling holes through my LSV, just never went 4".

Cleared inbox space.

Yes, the walls between the bottom of the seats and the floor. Drilling 4" holes in them to add more Heatercraft Hot tubes. I have a 4 port heater that's located under the seat cushion that's behind the driver's seat (the one that folds up as a backrest). and I'm only using 2 of the hot tubes now and have a couple more to install! so need to drill 2 more 4" holes

[MLA]

I use 1/2" corded drill, so pretty stout. I also use commercial grade hole saws and arbor like De Walt or Lenox. Those cheap multi blade kits will dull by the end of the 1st hole, making more work on the drill and you.

[sandm]

^this on the hole saws.
I did 2 6" holes for added speakers in the tige seatbases. I went a bought a 6" hole saw at home depot. was somewhat expensive(iirc around $25), but my dewalt 18v cordless drill did both holes in short order and both were very clean with no de-burring necessary.

sometimes right job=right tool....

[mmandley]

Never had an issue, I used a hole saw like that and my cordless drilled 13 2inch holes threw 2/4s no issues.

I have not drilled 4inch hole in the boat, but I have drilled several holes one after the other.

Personally I use reverse for only getting through the gell, once I am through that I switch it to forward and it eats like slicing butter.

I am pretty sure I have that same kit you have from the HF.

[jmvotto]

I did three four in holes with my 18v Makita1/2 drill no swear, tapped and in reverse . Like butter.

[trayson]

Never had an issue, I used a hole saw like that and my cordless drilled 13 2inch holes threw 2/4s no issues.

I have not drilled 4inch hole in the boat, but I have drilled several holes one after the other.

Personally I use reverse for only getting through the gell, once I am through that I switch it to forward and it eats like slicing butter.

I am pretty sure I have that same kit you have from the HF.

I never had problems with 2" holes. From what I can tell the difference between a 2" and a 4" is 4x the amount of force needed, as the energy to radius ratio is the square of the increase in radius. so doubling the size of the hole is going to require 4x the amount of energy to turn it at the same rate. And I have to imagine there's a likewise increase in friction from having the circumference of the surface area the saw is encountering change.

[trayson]

I did three four in holes with my 18v Makita1/2 drill no swear, tapped and in reverse . Like butter.

Maybe it's just my cheap a$$ tired hole saw then... Because I tried 2 different 18v cordless drills and a 1/2" corded hammer drill as well...

[zabooda]

You should be able to see the condition of the teeth. Keep the drill speed at the highest speed and go slow.

[kaneboats]

drilling the holes is literally a process that takes multiple sessions of drilling over a day or days

If drilling anything takes a long time your bit or hole saw is either the incorrect one (e.g., wood bit on metal) or it's toast. A new hole saw will pay for itself in saved time and likely save your drill(s) too.

[trayson]

If drilling anything takes a long time your bit or hole saw is either the incorrect one (e.g., wood bit on metal) or it's toast. A new hole saw will pay for itself in saved time and likely save your drill(s) too.

So, since most bits are billed as either metal or wood, then where does fiberglass fit in?

[MLA]

You just need a general use bit, just a quality commercial grade bit and arbor. Those cheap bits are not sharp to start with and dull quick. The arbor wears out along with the double-D slot in the hole bit.

[trayson]

You just need a general use bit, just a quality commercial grade bit and arbor. Those cheap bits are not sharp to start with and dull quick. The arbor wears out along with the double-D slot in the hole bit.

Would this be good enough?

http://www.amazon.com/DEWALT-D180064-4-Inch-Standard-Bi-Metal/dp/B00005LEZR

[jstenger]

Yes, that is a good quality bit. You will also need the arbor for it.

[gregski]

A toothed hole saw is the wrong tool for the job. Yes, I know that basically everyone here has used them for fiberglass with success but that doesn't make it the right tool. You want some variety of a grit/grind blade. If I were you, I would buy this carbide grit saw: http://www.amazon.com/Lenox-Tools-2996464CG-Master-Grit-Carbide/dp/B0009EK6OM/ref=sr_1_2?s=hi&ie=UTF8&qid=1449772598&sr=1-2&keywords=lenox+carbide+hole+saw+4. I used a similar Lenox carbide grit saw in a 1-1/8" size for my through hulls and it was a breeze. No "run it in reverse" tricks required since it is the right tool - the description even says it's for "fiberglass, ceramic tile, laminates, and other abrasive materials".

[MLA]

If you dont mind waiting and willing to mail order, then get the carbide bit. If you need to finish the job, you can walk into your box store and get

http://www.lowes.com/pd_348118-28303-1772014_1z0wcj6__?productId=3361258&pl=1

http://www.lowes.com/pd_300697-28303-1779670_1z0wcj5__?productId=3358054&pl=1

[gregski]

...or a dremel with a rotozip bit. That's what I used to cut a large deck plate hole in the center locker. It worked well. Even a jig saw would probably be better than a 4" wood hole saw.

[ian ashton]

I drilled mine with my 18v Ryobi, took about 30 seconds. I think you need a better hole saw.

[MLA]

...or a dremel with a rotozip bit. That's what I used to cut a large deck plate hole in the center locker. It worked well. Even a jig saw would probably be better than a 4" wood hole saw.

Actually no. The problem with a jig saw is you have the base of the saw riding along the finished gelcoat surface. Even if you tape it off, the vibration from the saw is going to tear the tape and mare the gel. The other issue with a jig, is having room to swing the body of the saw as you make your cuts, not to mention drilling a pilot hole for the blade. Two if its not a round hole.

Rotozip type tools will make fast work of fiberglass for sure, but you have to be super careful to not let them get away from you and color outside the lines if you will. I wont use them for round holes if I can use hole saw. The rotozips work for square or rectangle holes or off shaped holes. Even then, a 10" sub hole will typically kill a bit and on occasions, break one. I havent used my Roto in about 2 years now, moved on to a better tool.

[trayson]

I drilled mine with my 18v Ryobi, took about 30 seconds. I think you need a better hole saw.

There ya go. I've been using 18v Ryobi's... so I guess it's the hole saw for sure.

[parrothd]

You have the drill spinning the right direction? Lol..

[trayson]

You have the drill spinning the right direction? Lol..

As long as I do the drilling in the Northern Hemisphere, yes, but if I take my boat to Australia, I'll probably have to get one of those right hand drive drills.

I mean, my drill IS pretty amazing. I can't imagine why it's taking so long... But you should see my biceps now...

http://www.lifeprint.com/asl101/images-layout/hand-drill.jpg

[parrothd]

Just checking, running it backwards won't cut like you describe.. ;)

[trayson]

Just checking, running it backwards won't cut like you describe.. ;)

I've run it forwards, backwards, and everything but sideways. LOL.

[Dusty's Mom]

Go figure, trayson can't find the hole.

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[MJHSupra]

My neighbor came over the house asking to borrow my 1/2" drill. I give him the drill and ask him what the project was. His response was using a hole saw but having trouble.

I walk over to his house, pick up his drill, noticed it was in reverse. Ouch!

Plus, he was using crappy bits/blade kits from one of those discount tool places. After 1-2 holes it was done. F'ing junk.

Trayson - a 1/2" corded hammer drill does NOT work? Damn, is that boat made of Brazilian walnut?


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[dusty2221]

Go figure, trayson can't find the hole.

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Mom said he tried to put the 1/2" hammer on her, same story....drill a little one night, come back the next. After multiple nights the job still wasn't done

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