round holes, strange pegs

[CSS-Registry]

hello all,

i am getting ready to drill the necessary holes in my truck's sheet metal to facilitate installation of the one inch stainless trim.

i would like perfectly ROUND holes for my truck. i believe the holes to be in the 5/16th neighborhood and will double check before drilling or stamping.

question is: in YOUR experience what is the best way to get a PERFECTLY round, burr free holes in sheet metal?

i am considering purchasing the Rotabroach cutters (http://www.blairequipment.com/Rotabroac ... tters.html) but have no experience with them. i own various types of drill bits and my hole making experience is hit or miss in getting them round and burr free.

opinions please.

Ben

[Panelbeater02]

I always use an 1/8 drill bit first to drill a pilot hole. Use nice sharp bit, and do not press too hard. Also make sure the drill is 90 degrees to the panel.
When it goes thru, keep the drill running and move it up and down once or twice. Should be round and burr free! I always drill all mounting holes before painting, so as to not have a bare metal edge on the hole. I like to put a non hardening caulk on the stud, or clip, to seal the hole from leaking/corrosion when I install the molding.
Panelbeater

[CSS-Registry]

thanks for the reply....

i have drilled my fair share of holes and have used your described technique but i am not consistently getting round holes - sometimes they are triangular and or full of burrs.

your other suggestions are excellent... i plan on drilling the holes before paint but hadn't thought of calking them. i was thinking of using a little seam sealer...

i am going to buy the Rotabroach's and give them a shot at drilling round holes... besides it is always nice to have some new tools :o)

Ben

[Russ]

I did mine exatly like panelbeater said. I used clear silicone on both sides of the clips when I installed my trim. All of my clips were either plastic or the type with a nut on them so they should't have sctatched the paint when I installed them but the silicone was insurance. I also drilled a 1/8th pilot hole before drilling the 5/16th holes.

[centralwildcat]

Good thread ya'll, all suggestions helpful!! mattc

[Russ]

When I mentioned that I used clear silicone on both sides of the clips what I should have said was that I used it on both sides of the hole. I put it on the back sike of the clip and then put it on the under side of the body before putting the nuts on the clips. I covered the back side of the plastic clips too. Another thing I didn't mention but is probably pretty obvious, is that you should assemble the truck and line up the hood, doors and bed before drilling the holes or the trim won't line up later.