Timber Framers Guild Forums General General Forum Questions layout on timber with varying dimensions

I am trying my first project based on the 12x16 shed described in the Sobon book. I have a cheap ssource of dry 8x7 white pine but the lumber was cut with a band mill and the width can vary up to say 1/2 inch. The Sobon book describes a square rule method in which each timber is first squared to a true dimension-say 8x6 1/2 in my case. Is this as big a pain as it seems? Should I go to the mill and get fresh sawn timber with truer dimensions. I dont see how pieces will fit if the width varies but I hat the idea of all that extra work if not really necessary.. I could measure from a center line but dont think that will work. Can someone tell me what is most practical when timbers are not all exactly the same width-but close? I have done the stub and end tenon on 3 posts and hope I dont have to scrap for a 1/4 "to1/2" variance on the timbers.
Thanks,
Bob

Hi
You can go with two reference sides or center line. I'd suggest center line for inside timbers and two reference sides for perimeter and any wall adjacted timbers in general.

Good luck
Michal

I think you are missing the point of square rule joinery. The whole idea is that differences in the dimensions of the timbers are accomodated by making all of your measurements from the two reference faces and housing your joints. By housing your joints, you are effectively squaring off your timbers, but only at the joints - it is not neccessary to do it anywhere else.

You may find the discussion of square rule joinery in Jack's other book to be helpful.

Regards,
Dan

DO NOT SCRAP ANYTHING.

Study the square rule lessons more closely.

You will experience the 'ah ha! phenomena' shortly.

Thanks for the replies.I did measure from the centerline and when the timbers are laid on a flat surface next to each other, the tenons are not on the same plane. They vary slightly due to variation in width. In theory, the stub tenon in each post is in same plane as the centered tenon at the top of the post.If the mortises in the sill are in a straight line or plane,wouldnt that mean the top tenons will be in same plane but the sides of the timbers wont be in same plane. I think the outside face of the logs will not be in plane. In my case, fairly small difference but still a difference.If I had measured from the outside reference side, the outside of each timber and tenons would be in alignment?
Assuming the mortises in the top plate are in the same plane and the top tenons are in the same plane as , I guess ,the timbers should be in same vertical plane.If I house the mortise for the end sill and girding beam by reference to the outide of the end posts , then I think the pieces should fit based on comments above.
I wanted to get my thoughts in before I leave the house today in hopes I can generate another response today. I will reread Sobon but I found the explanation confusing.(I dont believe Benson book discusses this). I am not the best at understanding drawings, but I am game and will persist.
Thanks,
Bob ...3 posts of experience

As Joel said, "don't throw anything out!" And don't cut any more until you reach the "ah ha" stage. It's all about the reference faces and getting themm right with each other. As long as your joinery is layed out from the reference, the wood on the non-reference side doesn't need to line up. Your reference is almost always the outside surface and one other surface or the outside and a centerline. In either case you are referencing in two dimensions, creating a reference "edge" or intersection of the two reference planes. This intersection is your arris and it allows you to line up with the arrises of other members.
It is like riding a bike for the first time- suddenly everything clicks and it works! If you can get the chance to work with someone who is familiar with square-rule, it will come quickly.
Get to a Guild workshop of rendezvous- you'll find the experience immeasurably valuable. Good luck.

Hi everyone:

What fun, well for my 2 cents worth on this subject and from my experience working with hewn timber where all timbers vary at times dramatically what I would do is this--

For the exterior posts I would work with lines 2" from the outside surface--do all your layouts from this line forget the inside surfaces for now.

overall width measurements would be calculated from this line plus 4" (2" on each post beyond this line)

As stated above you will have to cut varying depths of seatings into the inside surface of the posts at the points of intersection of cross girts, and I might add all brace seatings.

Some posts like corner posts will be much trickier because of girts and braces coming together on 2 of the vertical surfaces from 2 different directions. For these posts you will have to work 2" from two of the best and squarest sides.

You will find that not many bandmills will provide you with timber much better than you already have so you might just as well work with what you have.

Large companies would take time to resaw, or plane the timber perfectly true (or very close) in the end it would save them much time and money.

The centre posts though will be easier just work from a centre line as has already been pointed out above.

Make no mistake when you have finished this small shed you will look at a large timberframed
building with awe realizing that the tradesmen that put that all together was working with timber of varying dimensions, hewn rough surfaces, and in many cases twisted just enough to make life very interesting.

Good luck on your learning experience, I am sure it will turn out well if youlisten to those that that will try and give you advice.

NH