Actually, all my red oak was radio frequency/vacuum kiln dried. Thought that would have made things more stable. This post by far has the most checking of anything in my house. Maybe this was really green when put in the kiln. Could be as I understand these longer timbers were harvested late -- or so I was told. These timbers were milled with a Hundegger so tenons and mortises had the curved ends. Many of the tenons were not bored until put into the mortises and held by come-alongs -- then they were bored and pegged. Obviously not offset bores!

I am an experienced engineer, but a novice timber framer. So, take these comments for what they're worth.

Looks like you've still got about 3/4" of bearing between that beam and the post. That's probably sufficient, but you might want to check your loads.

It's also fortunate that the check is perpendicular to the pegs, so it doesn't compromise the tension-perp-to-grain strength.

My guess: you don't have a structural problem here, only an aesthetic one.

I don't think you're getting any wedging action from the rounded edge tennons.

It looks to me like you're getting splitting and shrinking due to drying. I know you said they are RF kilned. Did you put a moisture meter on them? If so, did you check internal MC?

I might be barking up the wrong tree, but isn't RF drying pretty tricky to get right? Maybe the surface of the timbers were dry, but internal MC was still high.

That post sure looks like a "cut green, dried in place" timber to me.

I have to second jshaw in the first place.

What else to say... It is not a wedging because the post is split above mortise even more than below and goes all the way up. From the pics it is obvious that girt does not twist and the way it checks below mortise is typical moisture movement. I think the post was green when cut.

As to stabilize beams, there is only one way. Proven by centuries. Log your trees in winter, bark them, and season them for at least 6 months. Then you can mill them. 75% of moisture content movement will happen in those 6 months, providing it was barked

Michal

So if you remove the bark and let the log season for 6+ months, will the log check? Will that checking be much less than if you milled it? What would be a guess as to how much it could be reduced?

if you don't like checking work with steel.

Arborite anyone?

Timber is warm, has texture and will check no matter what you do.

If you season timber before milling, checks will be smaller than in unseasoned wood and beam will be more stabilized (less twisting, smaller changes in size).

There isn't any advantage to seasoning in the round or even very much oversized as I see it. The larger the timber, the greater the stresses as it dries. 1x and 2x stock doesn't check very much compared to larger stock. It is hard to keep a pile of round stock piled safely or supported adequately.

The surface checking and movement of the fresh sawn brace mentioned earlier was caused by too harsh a drying environment. If the surface dries enough to shrink before the core has begun to shrink, the buttons are gonna pop. As soon as drying stress ecxceeds tension perp, a check initiates. Much like tearing a piece of cloth, it may be relatively hard to start the tear, but once begun it keeps tearing pretty easily. Oak needs a pretty mild drying environment.

PEG might help reduce checking but can cause finishing problems. Other glycols have been reported to have some of that benefit... they dry very slowly and might help to keep the surface cells bulked while the core loses some moisture. Remember a cell doesn't begin to shrink until it is below around 28%.

Moisture content is basically the same winter or summer, sometimes even higher in winter with no transpiration going on. Always way above the fiber saturation point of around 28%.