Hello, thanks for the forum.
I am using a Harbor Freight Central Pneumatic nailer on 2 1/4 red oak. It fires well and puts the 2 inch staple in clean but I have seen tongue cracking on my test shots already. The wood is Lumber Liq. Colton mills. Not too bad looking...rustic grade.
Should I use the installed 25/32 shoe or the other 1/2 shoe? The 1/2 would raise the staple eh?? then it would not go directly into the tongue
step. What do you think? Experienced info would be great.
Also I noticed the 2 inch staples go plenty thru the 3/4 inch OSB T/G under layment. I dont want to add on any more underlayment.
I worry a little bit about hitting Romex ...I dont know how it was installed under the joist bays. Probably ok but I still worry.
If I used 1.5 inch long staples They would protrude just a tiny amount. Can I use 1.5? Most sources say use 2 inch for 3/4 oak solid.
What do you say??
In my test shots I also saw how a board can lift ever so slightly and make a seem on the next board. What do you do???
I am doing 620 sf.

1. Try backing the air pressure down on the regulator to about 80psi.

2. Your wiring should be at the bottom of the floor joists, not in the bays.

3. 2" staples will be fine, refer to #2

4. If it is pre-finished, character grade, from LL, that's what you get without sanding.

i am on 75 psi, that seats staple good. any more is too much with this new compressor.
what is #2?
this is unfinished oak
I can see now that you could just screw this down and it would probably be ok,, albeit lots of screws....
if 1 1/2 comes out the bottom of the OSB ,how could it not be enough?? how about 1 5/8 length?

LL Rustic grade is prone to splitting at the tongue. I would go with 1 1/2" staples, and dial down the psi as low as possible, ofcoarse enough to still slightly countersink the crown of the staple. Rule of thumb on fastener length is ," minimum of twice the thickness of the wood". I have used 1 1/2" fasteners many times, as long as I'm not using an underlayment thicker than felt.

Re: "Board can lift ever so slightly and make a seam on the next board". I'm not clear what your describing here. If you loose lay boards together ,without fastening ,do you have this problem?