cwaters
New Reader
4/12/13 2:02 p.m.
Not specifically motorsports related but you guys would totally have this answer.
The wood deck on my 4x8 utility trailer (typical kind) was rotten so I got a new sheet of plywood and ripped the old one up. It was bolted to the frame with some carriage bolts (I'll be replacing them as they're pretty rusty).
What's got me stuck is, how does one drill the holes in the wood for the bolts? Once I lay the plywood down, I'm covering the holes in the frame. Can not drill up from the bottom because I'm blocked by the frame.
I thought I could lay it down and scratch the wood through the holes from the bottom, flip it over and drill where the scratches are. But I keep thinking there must be a better way that I'm just not seeing.
What would GRM do?
use the old deck to mark the new holes
the local hardware store probably carries 'hole transfers'. Basically it is a plug that goes into the bolt hole and has a point facing out. You lay the plywood in place and give it a good tap with a hammer/mallet. The point will leave a dent where you need to drill.
Alternately, you could do the same with bolts threaded in the trailer frame backwards to have the threaded section facing up to make the transfer marks. That would be a good use of the the now rusty and soon to be in the trash carriage bolts...
cwaters
New Reader
4/12/13 2:14 p.m.
DaveEstey wrote:
use the old deck to mark the new holes
Would be a good idea if the old deck didn't look more like shreadded wheat than plywood.
If you have direct from bottom access (to put the nut on the carridge bolts) can you drill up from below?
(probably dumb question)
Sonic
SuperDork
4/12/13 2:25 p.m.
Lay the new deck in place and from underneath mark the holes with a sharpie, then flip it over and drill
Short bolt and nut, inserted from the bottom. bolt up through the bottom, nut on topside to hold it in place. Lay plywood on top and tap with a hammer. You'll have the perfect indentions where to drill the holes.
If I had much of a problem laying on the ground to do stuff...I'd probably have chosen a different hobby long ago 
That said...I did employ the help of 11 friends to flip my trailer over so I could work on the bottom side. But in my defense...that was for welding...not marking bolt holes.
Can't lean it up against the garage so you can get at the holes? Not quite vertical but close? Or do the tail lights prevent this?
cwaters
New Reader
4/12/13 3:34 p.m.
I'm going to to with the "bolts through the bottom and whack the wood" idea.
The frame of the trailer is like a [ so I can't drill up from the bottom because the frame blocks access. I can certainly lay down and reach the nuts once the bolts are in.
I'd probably have done the Sharpie thing but I just painted the wood black (had several cans of black on the shelf)
Thanks for the ideas.
mtn
PowerDork
4/12/13 3:36 p.m.
cwaters wrote:
I'm going to to with the "bolts through the bottom and whack the wood" idea.
The frame of the trailer is like a [ so I can't drill up from the bottom because the frame blocks access. I can certainly lay down and reach the nuts once the bolts are in.
I'd probably have done the Sharpie thing but I just painted the wood black (had several cans of black on the shelf)
Thanks for the ideas.
No white out? Silver sharpie?
Use a piece of thin cardboard or poster board as a template for one corner section and just rotate it around the edge of the plywood.
cwaters
New Reader
4/12/13 3:46 p.m.
mtn wrote:
cwaters wrote:
I'm going to to with the "bolts through the bottom and whack the wood" idea.
The frame of the trailer is like a [ so I can't drill up from the bottom because the frame blocks access. I can certainly lay down and reach the nuts once the bolts are in.
I'd probably have done the Sharpie thing but I just painted the wood black (had several cans of black on the shelf)
Thanks for the ideas.
No white out? Silver sharpie?
well... might have some white paint rattle cans and one of those red straws from a WD40 can...
mtn wrote:
cwaters wrote:
I'm going to to with the "bolts through the bottom and whack the wood" idea.
The frame of the trailer is like a [ so I can't drill up from the bottom because the frame blocks access. I can certainly lay down and reach the nuts once the bolts are in.
I'd probably have done the Sharpie thing but I just painted the wood black (had several cans of black on the shelf)
Thanks for the ideas.
No white out? Silver sharpie?
Sharpie. Lay underneath and mark the hole position onto the underside of the wood. Pull wood up, flip it over, and drill your holes where the marks are. That's much more comfortable than being under your back and drilling holes while having wood chips falling on your neck.
mtn wrote:
No white out? Silver sharpie?
I always keep a bottle of bright red finger-nail polish in my garage for marking things. :-)
David
Abandon old holes, drill new ones. BTDT. I usually put them down with drill and tap flat head screws.
Something like this.
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