Help! DIY board fence installation. When/How to trim posts.

[mstraebel]

Knee deep in big DIY project--6 acres of 4-board wood fencing. We have the posts in and boards are coming tomorrow. Posts vary in height slightly and will need to be trimmed. Do we trim now at anticipated top height of top rail, or do we wait until top boards are actually up? What tool is most efficient? We have 300+ to trim and they are 5" diameter round pressure treated. Tried circular saw today. Awkward for me! Tried small chain saw. That worked a bit better.

Also, if we wait until boards are up, how do we trim posts flush with top board without knicking/cutting into top board. We want posts level or slightly below level of top board.

Also, with pressure treated lumber, how crucial is it to cut post tops at an angle for rain run-off?

Thanks!

 

[Fixemall]

I have only done a small amount of two board and trimmed tops at slight inward angle using saws all with long wrecking blade, I made a field jig from scrap wood and used a pair of large jaw welding vise grips to hold it in place while cutting, this allowed all cuts to be the same and it turned out clean, straight and neat.
I trimmed after the rail boards were secure and level.

 

[Western]

I would trim them after the top rail is up. You may want to make elevation changes to get the top rail to look the way you want it, I.E. "straight" or "sloped" with the terrain. With the boards un-cut, you have some wiggle room.

I would use a good sharp chainsaw, one guy could probably cut faster than another picking up the pieces.

 

[MotorSeven]

I would trim them after the top rail is up. You may want to make elevation changes to get the top rail to look the way you want it, I.E. "straight" or "sloped" with the terrain. With the boards un-cut, you have some wiggle room.

I would use a good sharp chainsaw, one guy could probably cut faster than another picking up the pieces.

^
what he said:thumbsup:

A chain saw is the way to go and I can add if you cut them on an angle thay will last longer as that will shed water. Another benifit to cutting them on an angle is that trying to get them all looking perfectly even on a 90 degree using a chain saw is difficult.

 

[radioman]

I would trim them after the top rail is up. You may want to make elevation changes to get the top rail to look the way you want it, I.E. "straight" or "sloped" with the terrain. With the boards un-cut, you have some wiggle room.

I would use a good sharp chainsaw, one guy could probably cut faster than another picking up the pieces.

ditto here too !:thumbsup:

 

[Carl_NH]

I agree cutting with chain saw on the angle. Another tip since you have your posts in is to run a line say 2" below the top for about 80-100 feet then cut above the line before you put on the rails.

This allows you to follow the grade changes and use a jig that hangs from the top of the post with spacer boards for equal rail spacing. I would make 2 jigs - one on the previous and one on the next post

Also you will probably find that not all posts are exactly 8-10' apart and your rails will need to be cut so attach the rails then cut with a skil saw in the center and use the jig as a side rail (for a straight cut) by screwing it to rails top/bottom.

 

[dieselscout80]

I used a chain saw to cut mine at a 12° angle after the rails are up and the top of the post is 1" above the top rail.

To do this I made backet with a hanger the fit over the top rail on both sides of the post. I also made bracket that I bolted to my chain saw bar that would hold the saw at the 12° angle (had to drill two hole in the bar) and engaged a slot in the bracket hanges on the top rail.

The brackets are made of steel strap and angle about 16 gauge IIRC.

I used small Mcculloch Eager Beaver that is easy to handle. One lesson learned is have the saw's clutch facing down other wise the chips can jam the clutch/brake.

A Skil saw would work too if it can cut the posts I know a fence builder that uses a 8.25" or 10" skil saw and generator to cut posts. The standard 7 1/4" saws will not fully cut most posts.

I worked real slick.

 

[KennyG]

For a project the size of yours, I would probably go with the chain saw angle cut. However, for a small project I have marked a level line on all four sides of the post, and then used a circular saw set at a 30 degree angle to cut all four sides. This gives you a pointed end. It looks good and drains really well. Too much work for a big project though.

 

[beppington]

Definitely do not cut the posts before the boards are on & you're completely happy with how they follow the terrain. Once you cut them it's too late to make any changes, if say you attach the boards, then look at it from a distance & decide the up/ down curving transitions are too sharp/ harsh.

In fact, I'd attach the top rail only on the entire fence, stand back & look at it, & make sure you're pleased with how it flows & looks before bothering to put the other 3 lower rails on. Get the top rail exactly right, then put the other 3 on.

It's amazing how you can be standing close to the fence while working on it, sight down the rail & think it looks real good & smooth ... & then when you stand back from a distance the rail looks too bumpy / herky jerky, ie too much up & down, vs smoothly flowing over the terrain.

 

[BeezFun]

Unless you've got power out there, you might also use the chain saw to cut the rails. Nail it up, cut down the centerline of the post, then butt the next one. If you have horses I assume you're going to electrify it, or else buy lots of spare parts.