I've had to do this before and usually try to attach a piece of plywood so the pilot drill can get a bite for the hole saw to start.
This looks like a good solution, use a hole saw the same size as the existing hole as a guide with the larger hole saw mounted above it:
Your solution will now have my granddaughter allowing her three boys be in the shed when I am opening up a hole. Thank you for me and them! :)) ^.^d
Thanks for sharing. This will come in handy.
Jason
What a great tip! Thanks.
jor
That works if you have a hole saw that fits the original hole and you want the hole in the same place. Good idea.
Sometimes you don't have the right hole saw or you need to move the hole to a new center just offset or a bigger hole not centered where the old hole was. Use the hole saw of the size you want and drill through a piece of 3/8 or 1/2 inch plywood. Position the plywood where you want the hole to be and use it to guide the hole saw.
This also works well when you do not want to use the pilot bit (like drilling a hole in the coach ceiling) to prevent it from going through the other side (the roof). I did this when putting up our bedroom ceiling fan.
Roger when you put up the ceiling fan did you screw the mounting bracket into metal? if so how did you locate the metal?
I am wanting to mount a TV bracket to the ceiling but I'm not sure where to mount it.
Thanks
Chris lang
Chris, in the bedroonm ceiling in my coach there is a 12"x24" plywood panel (2-3/8" layers) right in the middle of the bedroom ceiling. There is also a PEX tube embedded in the foam above the plywood the goes over to the ceiling of the BR TV cabinet.
You drill through the ceiling material, the fiberglass layer and a thin plywood layer, the 3/4" plywood and another 1/2" or so into the foam and the PEX tube. The fan mount attaches to the plywood. This panel is not in the 1997 coaches. I am not sure when it was added. You can get a roof plan for your coach from James Triana. I have mine somewhere, I'll keep looking.
If you are lookinf for roof structure it is aluminum. A better quality stud finder will locate them easily. These are not cheap but one of the best you can get.
ProSensor 710 Franklin Sensors ProSensor 710 Precision Stud Finder Yellow -... (https://amazon.com/gp/product/B0064EICKG/ref=oh_aui_search_detailpage?ie=UTF8&psc=1)
Had to enlarge and offset my coach speaker
round openings on the bottom of my walnut cabinets by 3/8" of a inch tried a fine tooth jigsaw but it was still lifting the veneer. One speaker will now extend slightly below a tambour door. Ended up using my easily controlled drill with a small 1/8" bit to outline the hole as the drill is very easy to control location and cutting depth. Then used an old fine tooth hacksaw blade pushed towards the veneer to connect the dots or drill holes. Probably took me 10 minutes more per hole but I was able to catch cuttings as I drilled with a shop vac. Not exactly perfect, but easily accomplished with common tools.