How do I mark the bolt holes for securing floor to HF frame?

[tvlawyer]

I've aligned and clamped my deck to the HF frame. What is the best way for me to mark the location of the bolt holes in the HF frame cross members on the cross members of the wood deck?

I think I need to do it from below with a punch or marker small enough to fit inside the steel cross member. But, I'm wondering if there is an easier and/or more accurate way.

[Woodbutcher]

That is the way I did mine. Crawl under with a real shot pencil that fits inside the rail and trace the holes.

[Miriam C.]

Sharpie marker. They make them light if needed..

[absolutsnwbrdr]

I placed the plywood on top of the frame bolts and hit the plywood with a hammer at each bolt location. The bolt heads made small indentations where I could drill the recesses.

[TwilightLane]

I used a sharpie!!

[Steve_Cox]

For mounting the deck I drilled new holes through the plywood and the frame with stainless steel trailer deck screws



I also located the trailer bolt heads with a hammer and recessed the plywood for the bolt heads like pictured in the above post.

[H-Balm]

I did it like absolutsnwbrdr.

I put the bolts into the frame.
Then put the floor down.
Whacked it with a mallet.
Flipped it over and drilled where the dent was.

[3822sean]

i did mine like the woodbutcher under with a short pencil

[cracker39]

Drilled up through mouning holes from beneath the trailer. Using a small portable drill stand to stabilize the drill, I drilled my countersunk holes for the carriage bolts with a forstner bit that was a skosh wider than the bolt heads so that the bolt heads are subsurface. I filled the holes by pouring Bondo resin in them so that it formed a small bubble above the floor and sanded smooth when the resin had cured.