You route in the direction opposite the grain so the cutter isn't cutting into the grain. To make that clearer, you look at the corner you're routing. Assuming the post is vertical, you will notice that the grain is not straight down the length of the post. If the grain is slightly diagonal, going toward the top, you will start from near the bottom. This will avoid chip outs that would often happen if you started from the top with the cutter gouging into the grain. You'd have to check all four corners because that grain pattern would be reversed on the other side or opposite corners.

If you're using a trim router for this purpose, I'd not make it more than a quarter inch round over, with a bottom mounted guide bearing. I'd let the bit cool down a little before starting another side. With a quarter inch shank, the bit is more vulnerable to coming loose and flying off, so I'd stop every few passes to check the collet for both tightness and make sure the bit isn't bottomed in the collet, but about 1/8th inch from th
the bottom. You don't want to be anywhere near that thing if it comes loose.

 

Thanks that makes sense. Since I just want to take off a little bit off the edge, probably only use a 1/8" or even just 1/16" round-over radius. Maybe the safest thing to do is to just hand sand the edges down.

 

The router will be much less effort, especially if there are more than two posts. I'd stick with the quarter inch. The smaller the roundover, the more susceptible is to dents and damage. Just my opinion. 1/16th, to me, doesn't make much difference. Aesthetically, I'd prefer the 1/4 inch.

 

Thanks Tom, I have two routers a pretty heavy Freud plunge router and a lighter Ryobi R163G router. I'm used to making horizontal runs, but I'm concerned about an 8' vertical run specially with the heavier router. I'll try the Ryobi and see how it does.

 

You bet. You might want to install a wide plywood or clear acrylic base to make it easier to hold the router in position. The Ryobe should do just fine for a quarter inch or smaller roundover. I mentioned the grain direction because construction grade lumber splinters pretty easily. Send a picture, I'm interested in pergolas and I'd like to see it.

 

What Tom said GatorBill. I see a few issues you may run in to. Tom mentioned the chip out which will likely happen. At the ends of the post you won't be able to reach it with the bit so some sanding will be needed. Unless you are very tall you will need a small step to complete the run, do a dry run before hitting the power. Try to get a smooth uninterrupted cut. Finally there is matching the finish/routed wood when finished. I would try a side less noticeable first and see how it came out and wouldn't rule out sanding just yet. Good luck and be safe.

 

Thank you Marco great advice about a dry run to practice the procedure. I'm knew that I'd be making at least two passes, one on the ground, and a second on a stepladder for the upper part. Naturally, it's the upper half that has me concerned. I saw a YoutTube video where a guy used a small plane with a shallow blade setting, then holding it at 45 degrees to the edge of the column in order to shave off the "sharp 90 degree edge".

 

Welcome to the forum.

 

You got my curiosity up because I'd seen a small specialty plane just for doing chamfers and roundovers by hand. Price for this one is $36 for a complete setup. Not bad, and a simple alternative. The same grain direction instructions apply to avoid chipout. I love using hand planes, so I ordered one. I'll review it sometime.

Also, I forgot to welcome you to the Forum. It's a nifty bunch of pretty skilled people who love being helpful.

Amazon.com: Tidorlou Chamfer Plane with 7 Cutter Heads for Wood, hand planer for Woodworking,chamfer Planer for Quick Edge Trimming,Portable wood planer: Home Improvement

Amazon.com: Tidorlou Chamfer Plane with 7 Cutter Heads for Wood, hand planer for Woodworking,chamfer Planer for Quick Edge Trimming,Portable wood planer: Home Improvement

www.amazon.com

 

Thanks Ross and Tom, happy to join a nice friendly woodworking forum. Nice find Tom, I just ordered one of these to work on my patio cover column edges !!!

 

Over the years I've built two pergolas and in each case I routed a 1/4" round- over AFTER assembly. the unrouted top and bottom in my opinion enhanced to look. In both cases I used our very hard Jarrah, in the first one the posts were rough sawn and the second the timber was bought ready milled and if there was any chip-out on either, I didn't notice it.