Timber Framers Guild Forums General General Forum Questions Log scribing explanation

Hi all,
I've found interesting pictures from TFG workshop . I have a lot of questions how to connect crooked and curved logs with different diameters. But the first question is: could anyone give me just a brief and simply explanation of whole process on the pictures? Especially I don't clearly understand how to transfer lines and angles to logs.

Thanks in advance!
Ferd

Brief? Convert it to square and that will shorten the process. Silly log builders.

I don't completely understand the process in the pictures. It appears to me the carpenter has made a template to use as a basis for transferring dimensions from one timber to another. I have never done this, so I could only speculate on how it works.

I don't like joining logs together in the round, with contrary grain (that is, perpendicular or at an angle as shown). This is because of the way the wood will work in a round log so joined. I always prefer to reduce the wood around the joint in some way, even if the rest of the log is left round. This can be done to be very attractive and in keeping with the nature of the wood.

It's kind of like Tim says, convert it to square, only here it is only squared at the point of the joint. Study Norwegian log building, and you will see this is how they do it. I'd recommend you get the Book, The Craft of Log Building, by Hermann Phlepps, if you can find it. That will teach you a lot about working with logs as a building material.

Like Tim, I like things to be square. Even log walls, I like the wood to be square timber!

Thank you for reply. I think converting whole log into square takes more time. I know it is easier but it is different technology. Here are another interesting pictures by Joe Bartok. Some logs are converted to square and others remain round. Especially this valley housing makes me wonder. So I would like just to know how to transfer these angles to right places on round irregular logs.
Is here anyone who can explain the procedure? Or personally attended this worshop and can give some advices?

The logs in the link, if you look closely, are reduced at the joints to regualar rectangular dimensions. This will be your fastest and most efficient method.

Transferring round dimensions from one log to another in complex assemblies is possible, but it is time-consuming and difficult. There is much opportunity for mistakes, and it is very hard to visualize such joinery. Also, cutting the round profile joints that result is no simple task. I never bothered to learn how to do it, because it never seemed worthwhile. But that is entirely a matter of personal preference.

I wish I could help you more specifically, with the aspects of scribing round to round,

I have a 3d model of one of Roberts joints. I'll try and post a picture later. I was working with my little one at the barn raising (also in those images) - so I didn't see the whole process. I'll try to sum it up, and I'll invite Robert to post here.

When it comes to what is fastest,

round building is fastest for raising a relatively crude skeleton frame. This is seen historically, where round post construction or round log building happened first.
The disadvantage is in enclosure. You can make an undulating enclosure (that is, wobbly) easily, but to make a flat surface is difficult

The next step is to square surfaces that are going to have anything attached to them. For an example, look at the floor joists in many old barns which are squared only at the joints and along the top face. Another example is found often in Norway, where the interior surface is made flat while the exterior is left round.

Taking the whole structure into consideration, the fastest approach really is to square everything. This takes some time to hew or mill the timber, but from there on everything is faster. It is easier to envision and lay out the joints. The joints themselves, being square, are easier to cut, and the resulting frame is easier to close up.

However, I think maybe you are after the look of the round log building. If that's the case I would still recommend trying a reduced joint approach, where the logs are made regular at the joint locations.

Round joinery is a difficult skill to master and is labor intensive. From what I have seen, you don't find it historically.

All this into consideration, you are free to do whatever you want. If you want to learn scribed log joinery, that's great. There are few who do it. I've let you know why few do it, but if you still want to do it go ahead! Despite what might seem like skepticism from me, I do think it's a nice look.

I must say they did a beautiful job with their joinery.

I don't have much personal experience with round logs. So I'm only saying how I would approach it.

My first goal would be to envision the timber in the log. To do this I would start with a log a bit longer than the original dimension. I would rough cut square both ends as close as I could by sight. Then I would string a line from one end to the other in the middle of the top. This is a reference for the centre of the log. It will be a set distance above the centre point of your stock. If you need to offset this line at one or both ends with a plywood disc or square that is fine. Depending on your stock you might want to also snap a line. At this point you can square down off this line and left and right and establish a square end cut in relation to the line.
When your ends are cut square you can establish any point on the log with relation to an offset string line. Depth and mortise location can be determined by plumbing or levelling from the line.

We join round timbers quite often and it usually involves scribing with one piece set over another, then working off snap lines to level the pieces. A bubble scriber or laser level is used for round to round pieces or round to flat. For a description of the process. see issue #78 of Timber Framing or see the Timber Framing Fundamentals for the three-part scribing series I wrote. Both publications can be bought through the Guild store.

The Burlington process shown in photos indeed used a template and ground plane drawing. This was a radically new process developed by Rob Chambers because it allows you to join timbers of the same diameter (there's a mortise and tenon inside that joint). Previously one timber had to be at least two inches smaller in diameter to the other in order for the joint to look fluid.