I'm in the process of installing a handrail here and the former owner put these pressure-treated 4x4 posts without cutting them first. They're in the ground already and need to be cut at the correct height to where the railing itself will be attached.

Should I use a circular saw or something to cut from both sides? I already know it won't cut through with just one swipe on one side. Or maybe a good hacksaw or something? Thanks.

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  • 6
    There have been many times we've cautioned renters about making permanent changes to their apartments without written approval from the landlord. I think cautioning someone against making changes to property he doesn't own seems entirely reasonable. If, for any reason, the sale were to fall through, the current owner could attempt to charge OP with vandalism, no matter how well intentioned his motives.
    – FreeMan
    Commented Jan 20, 2021 at 15:46
  • @FreeMan - the flipside being the owner is sued for leaving unsafe steps for anyone to fall down...
    – Tim
    Commented Jan 21, 2021 at 15:38
  • Possibly, @Tim, however with only 3 short steps, A reasonable jury should find that one should be able to hold onto a post if one needed support, or that you should stay away from an obvious construction zone if it's not your own property. Of course, finding a reasonable jury is getting to be more difficult, but that's a different question.
    – FreeMan
    Commented Jan 21, 2021 at 15:45
  • Is your handrail going on top of the posts, or on the side? If on he side, I'd suggest you install the handrail first, before trimming the posts.
    – Criggie
    Commented Jan 21, 2021 at 21:14
  • @Freeman, "permanent changes" can't include cutting posts like that. Commented Jan 21, 2021 at 21:42

5 Answers 5


It's common practice to set posts and trim them to height later. It's more difficult than you might think to set a post to a perfect height, and you don't always have the angles in advance..

Our strategy was to strike a line all the way around using a carpenter's square, then cut from all sides with a standard circular saw (four sides for level cuts, two for angles, or all four if you set the table angle). Be careful to hit the marks accurately. This leaves you with about a 3/4" square or strip in the center that you'd cut with a hand saw or reciprocating saw.

If you do this carefully there's not much left to clean up. If you miss a bit you'll have some sanding to do.

  • I may still have out in the garage a guide I MacGyvered when I was building our deck. It consists of two pieces of aluminum angle and three pieces of flat aluminum, with screws through the angle pieces and tapped into the flat pieces, so that the assembly fits snugly around a 4x4. Clamp with a C-clamp and then use it as a guide for a circ saw. (I'd never have been able to hold the circ saw steady on drawn lines, but this worked great.)
    – Hot Licks
    Commented Jan 20, 2021 at 23:40
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    I am not going to put this as an answer but my guys have used a mitre saw (many many times) to do this. It involves 3 guys - 1 to hold mitre, 1 to clamp mitre to right location, and 1 to ensure accuracy and do the cut. Its about 30 seconds per post and perfect. It is hillbilly but its fast and relatively not dangerous. But most stuff gets a cap - PVC or metal - those posts... its chainsaw time.
    – DMoore
    Commented Jan 21, 2021 at 16:11
  • That's a clever idea, if a bit comical. I assume by "hold mitre" you meant "hold the saw", right? As opposed to holding an angle on the saw.
    – isherwood
    Commented Jan 25, 2021 at 14:08

I wouldn't use drawn lines to follow. Instead, I'd clamp a piece of scrap (?) wood to each of the sides, so it produced the correct angle - better still, use two longer pieces that straddle both posts.

Using an ordinary hand saw, cut from higher to lower, using the scrap as guides. A bubble will ensure both pieces are level with each other, when clamping.

  • A circular saw should work just as well with such a guide, in general, although in this case the post nearest the house probably doesn't have enough clearance. Commented Jan 21, 2021 at 14:31
  • @StayOnTarget - the depth of cut on a lot of those saws isn't that good. Given that the scrap woor might be 1", that means you'd need a depth of 3" to get half way. And circular saws aren't as easy to control as a steady handsaw.
    – Tim
    Commented Jan 21, 2021 at 14:51
  • Its subjective, but I think many people would find a handsaw harder to use than a circular saw. Depends a lot on experience. Commented Jan 21, 2021 at 14:52
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    True. I have 50+ yrs with both, and know which I prefer - and use!
    – Tim
    Commented Jan 21, 2021 at 15:30
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    @Tim, I'm not sure what arrangement you had in mind, but if you offset the scrap wood by 2" (or whatever it needs to be) then the scrap acts as a guide for the edge of the saw's shoe, and doesn't subtract from the depth of cut.
    – The Photon
    Commented Jan 21, 2021 at 22:43

The "idiot" who installed those posts did it using the normal way of installing posts. You always install them long then cut to length after they've been set. That way, you only have to worry about getting the post vertical during installation, and you don't have to worry about getting a pre-cut post to exactly the right height while trying to juggle 2 other dimensions.

Use a level to draw lines on 3 sides so that you can ensure your cut is level. You'll need this no matter what method you choose to cut the posts.

  • A hand saw will work just fine to cut them and won't take long or cost much.
  • You could purchase a circular saw and make 2 horizontal cuts, but if you're not used to using a circular saw, this is a good way to mess up your cuts and potentially remove bits of flesh from yourself.
    • I'd suggest not buying a "cheap" one. A reasonable quality tool doesn't cost that much more, will work better, and last much longer.
  • You could use a jig-saw with a longer blade to make it through in a single pass, but jig-saws are known for not cutting the straightest lines, and since this is (presumably) right by your front door, I'd imagine you'd like a nice looking post top. You could hide the slightly ragged/not level cut under some sort of post cap.
  • I find levels troublesome on such short runs. By the time you get around you're likely off a bit. A small square is the ticket, in my book. Otherwise, I agree.
    – isherwood
    Commented Jan 20, 2021 at 14:38
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    Agree, @isherwood, however, I thought I'd stick with terms the OP, a first time home buyer without, it seems, any tools at all, would know.
    – FreeMan
    Commented Jan 20, 2021 at 14:39
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    +1 for part one, however I strongly recommend AGAINST using a jig saw though. Half the time I use a jig saw for anything I regret it 100% of the time.
    – elrobis
    Commented Jan 21, 2021 at 15:41
  • That's why I included the warning, @elrobis! :)
    – FreeMan
    Commented Jan 21, 2021 at 15:46
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    No normal jig-saw will have enough depth to cut through a 4x4 post, and would be dangerous because of this. A better choice would be a reciprocating saw, with a sufficiently long blade.
    – Glen Yates
    Commented Jan 21, 2021 at 16:45

A hand saw may be a better option if you are cutting the posts at an angle. I would recommend a cross cut saw as a hack saw is usually for metal and may not cut completely through especially at an angle. A 12 point per inch 24-26” hand saw is what I use when I get in close quarters like the post next to the wall. Battery saws are great but not for every job.

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    Not a bad idea, but it's surprisingly difficult to get a cut on the intended plane with large lumber. A jig of some sort, such as clamped guide boards, would be a good strategy.
    – isherwood
    Commented Jan 20, 2021 at 14:53
  • Maybe I have been doing this for two many years as I can still get a good cut by hand where the saw would not fit so you would still need a hand saw or long blade on the recip saw , that would work but possibly not for someone without experience. The first time I saw my son in law try with my saws all he had over an inch of saw marks on either side of the line until I showed him how to start a cut then he did better, now after many years he can do a good job.
    – Ed Beal
    Commented Jan 21, 2021 at 17:39

How about a reciprocating saw?

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