Drilling through the Floor?

gspdx

I am starting the installation of tank heaters and was wondering if anyone has advice of the best tool to use to drill holes in the floor of the T@B 400?

I have a number of hole saws in various sizes and would like to just use what I have.  I also have forstner bits but the teeth are more aggressive than the hole saws.

Any other options? 

ScottG

I have no first hand experience drilling through the floor, but I'd start with a hole saw. Probably a deeper one is better--I'm not sure the total thickness of the floor but if everything is glued together you may need to get completely through with one cut.

N7SHG_Ham

I have drilled a small hole for wires, about an 1/8". It is a sandwich, Azdel, foam and Azdel. Bit drops through it like gas through a funnel, almost zero resistance. A regular hole saw should work fine, I believe it is less than 2" think, but certainly some thickness you may want to account for with a hole saw.

gspdx

Appreciate the feedback from both of you.  I will probably drill a small pilot hole to test the location and the thickness.  And if all looks good then use the hole saw.  With a pilot hole I can drill from the top and the bottom if necessary.  Planning to line with a PVC bushing and could use one from the bottom and top to eliminate any rough edges.  Then fill any gaps with sealant after the wires are in.

DougH

I created a 2.5" portal with a hole saw to create extra ventilation in the rear storage (with screening and a muffin fan).  Main preparation should be using a stud finder to find the aluminum frame elements, and avoid those.

Dalehelman

I used a 3” hole saw drilling from both directions. To draw warm air from the cabin into the under belly.

gspdx

Did a little exploring with the stud finder to see where to drill.  Not quite sure yet. It will be in the utility area under the wardrobe. 

If any of you have drilled through the floor in that utility area I would be interested in knowing the location. 

Thanks everyone for all of the info.

DougH

Not sure on the 400 how uniform the frame grid spacing is.  I seem to recall on the 320 it was something like 9 or 10 inches.  So you may be able to more readily find the frame locations elsewhere on the floor, away from the wardrobe, then measure off the distance to some tiny pilot holes under the wardrobe at several test points on the circumferential path you'll be cutting.  Maybe.  Unless someone more experienced has a better suggestion. 

Verna

@gspdx, try looking under the closet at the frame ground wire, where it goes through the floor and where it comes out, as that will give you an idea as to where you are. It appears mine has about a 3/4” hole just for the bare ground wire.

Tundra57

I took off the access panel under the fridge or wardrobe. I cut holes either side of the water pipe coming up the floor to the pump. I cut 1 1/2 holes. Using a Milwaukee hole saw. It's bit over an inch thick. Two layers of flat material, a layer of poly foam and a final flat layer. Hole saw cut no problem. Just make sure your exit underneath is clear. Like Verna said, find something passing through and get underneath to see it's exit then use a tape measure to locate yourself. I don't know which way the cross supports run. I missed them all. If you drill pilot holes you should not only drill a center hole but at the expected outer edges too in case you are close and the pilot drill just misses.

gspdx

I cut the hole in the evening yesterday.  I used the water line coming in to the utility area under the wardrobe as a guide.  Checking underneath the tank actually has a cut out area that goes around the water line and had enough space to easily add the hole I wanted.  So I ran a pilot hole with a long drill bit, left the bit in place and checked top and bottom to make sure I was happy with the location.  Everything looked good so used the 1 3/8 hole saw and that took about 10 seconds. glued a PVE pipe bushing in the top and bottom with a liberal amount of construction adhesive and it all looks good.

Time to start running some wiring today.  I will probably post up some photos later on the project.

Thanks to everyone here who provided info and advice.  You are all truly a great source and it makes this forum lots of fun and very informative.