drilling into garage floor

[prkaye]

I was trying to drill some holes in my garage floor, so I could screw some brackets down (I'll need to do this for my wing stands eventually).
I got a carbide drill bit and put it in my high-torque drill (big electrical drill).
I could barely make a dent in the floor, even applying considerable downward force.
Any suggestions?

[Kenneth]

Use concrete drill bits and a slow speed drill. Using regular drill bits on concrete will just dull your drill bits.

I just mounted my wing stands using 1/2" concrete anchors and found it best to drill a 1/4" pilot hole before drilling the big ones.

Good luck!

--Ken

[grjtucson]

Buy, borrow, or rent a hammer drill. It uses concrete bits but hammers and drills slowly at the same time. I have a "Bosch Bulldog" that is fantastic but pricey. Harbor Freight has very inexpensive ones. If you are like me, you'll end up using it more than you think.

George

[txaviator]

A carbide bit isn't the one to use. Use a masonry bit (inexpensive). Masonry bits are the 'funny looking' bits with a large 'tooth' on the tip. When drilling concrete, especially older concrete, like Ken said- it's best to drill a smaller pilot hole first (smaller masonry bit) then the actual hole size. Remember that concrete continues to harden for over 20-years until reaching its hardest form. Use lag shields (made out of lead) to hammer down into the holes. BTW, the lag shields will tell you on the side what size lag bolt to use and what size hole to drill in order for the shield to fit tightly/properly in the final hole.

And remember, slower drill speeds work better for drilling into concrete, and be sure to drill deep enough for not only the lag shield to be completely flush with the surface, but to also facilitate the overall length of the lag bolt when it is inserted through the stand (etc) and into the shield. In other words, you don't want your lag bolt bottoming out into concrete before it has a chance to be fully inserted. Lag bolts, lag shields, masonry bits...cheap, cheap, cheap. Probably < $20 for everything.

Let us know how it works out.

[prkaye]

Awesome, thanks guys. I saw "carbide drill bit" and read that it would drill through steel, and naively figured steel was harder than concrete...

Sort of related question - Rudy has those sweet metal wing stands that don't need to be anchored in the ceiling. Where can you buy long rectangular steel posts like he used?

[briand]

Your local steel yard. I built mine for $12.00 ($1/ft). 9 Feet of 1x3 steel tube and 3 feet of angle. A lot of builders use 2x4 but the 1x3 is plenty strong.

[tinman]

I glued 2 x 6 wood blocks to the floor with construction adhesive, then screwed my brackets into those. Once done with the jigs, I used a pry bar to remove the wood blocks. The result- no holes left behind. The construction adhesive is very strong and smells good while curing :-)
Hmmm...perhaps I could use a good huff right now!

[briand]

[prkaye]

>> 9 Feet of 1x3 steel tube and 3 feet of angle

Is that for one wing post, or a pair?

>> I glued 2 x 6 wood blocks to the floor...

No holes, but how did you manage to get the adhesive off the floor?

[Slingshot]

If you are drilling into concrete to secure the Van's "wing jig" the drilling might not be necessary. An instructor at a EAA Workshop gave us two methods to achieve similar results. 1. Place the 4x4 in a small puddle of Bondo, get it straight and let it cure. It will hold extremely well. To remove it slam the 4x4 hard from the side with a hammer and it will pop off the concrete leaving little to clean up. 2. Get some of this rubber waffle like stuff you would use to keep things from slipping on your bench top. Place that under the 4x4 and it will not slip away.
I used #1 and it worked great. The 4x4s lasted through to whole wing building process and are now ready for removal.
Good luck.
Bob