You have the basics right but you don't have to vacuum, that's what the extra 1/4" is for. The head type is dictated by the application. Hex heads are easier to drive but if you need the head to sit flush...

Tapcons are somewhat time consuming but they work pretty darn well. They are much, much slower than powdered actuated fasteners though. If you have a lot to do, you might want to consider renting one of the auto feed Hilti's for the day.

As for a hammer drill, buy or rent a ROTARY hammer drill. They drill much faster than an ordinary hammer drill. The quick way to tell the difference is the chuck -- rotary hammers have an SDS chuck. If I recall correctly Tools of the Trade (dot net) did a review of light duty rotary hammer drills within the last year or so.

Good luck!

Thanks for your help, Mike. I'm heading to the rental center this morning!

I'm thinking that Platon's 2' grid pattern may be a lot of overkill...ending up 15 tapcons per sheet! Others who have used Platon or Delt FL talk about just enough to hold the 4 x 8 OSB's in place and to get rid of any springiness in the flooring. Hopefully this will become evident as I go. I suspect once the tapcons are in good they won't come loose.

So have you started on your project? If so, how did the Tapcons work out for you?

I have yet to encounter anything that a plain old hammer drill could not get through for the small sizes tapcons use.

I use rotary hammers and even diamond tooling for larger holes.

Use the tapcon drill bits.
They are the correct size (and one should be in the box of 100 screws).

For doing a number of tapcons the kit with the driver sleeve is worth the price.

Brickeye,

Not to quibble but when you have lots of drilling to do a rotary hammer is simply more efficient than a hammer drill. It's not that a hammer drill won't work but rather the rotary hammer will make things go a lot faster. There is also less vibration because of the design of the tool.

My rotary hammer is much larger than a typical 3/8 or even 1/2 inch hammer drill and uses spline drive.

I could not even purchase bits small enough for a tapcon.

This sounds like marketing voodoo to create the impression something is 'bigger' and 'better' by confusing it with a much larger tool.

The hammer drill goes about as fast as you can drive it for theses small holes.

I just put in about 100 tapcons. 3/8 hammer drill took 5 minutes a hole to drill in very hard concrete - some spots where I was hitting a large piece of rock it would not even do the job. Broke out my old Hilti Rotary drill and it took 5 seconds a hole. HD has SDS bits that fit the tapcons.