Timber Framers Guild Forums General Off Topic Wiki Good :)

I'm liking the Wiki. I think it will be a great tool to so many and eliminate the need to search the archives for the possibility of an answer, or having to constantly repeat them...

I was going through the glossary.
Collar Beam entry stated "also improperly called collar tie"
This may be where some editing needs to come in, cause I've always known it as a collar tie, and if that is wrong I would like the explanation.
And....if something is "often" referred to as something other than it's original name, it's usually accepted as an alternative name, (along with an explanation of why it's used).

I'd be all over it if I had my facts....

Hi Christina,

I have had a go at rewording the definition for COLLAR. It is not a COLLAR Beam just simply a COLLAR. Does the ammended defition meet with your approval ?

A tie would suggest a member in tension and collars are generally in compression hence the "improper" reference is correct.

Your post is not Off Topic and would be best placed under the Wiki and FAQ entries.

Regards

Ken Hume

Hi, Ken -
That's the stuff I like to know
That, and where to post, apparently....
Thanks for the input!

In timber framing each timber is given a name based on its location in the frame.
A tie beam usually ties two walls together going from post to post, but they can go from plate to plate. A collar beam usually goes between two rafters.
Tests by Ed Levin have shown that collars only "tie" rafters together when they are as low as one foot above the foot of the rafter, or lower.
Once someone suggested three different names for "collars" based on their elevation between the rafters. I don't recall all three names but I usually call and collar a collar beam and not a collar tie, as the word tie implies it is tying the two rafters together, when in a lot of cases it is in compression holding the two rafters from sagging.

Jim Rogers

Tie beams under collars. Do they come in different shades of blue, with patterns? Tim

Websters...collar... (mech.)...used for restraining motion within given limits.

Who is to say what direction of motion the collar tie is restraining, out ward or in ward motion. The tie is keeping the rafters locked in this position. In the case of a collar tie it is simply tying the rafters together, keeping them from sagging, or coming together, restraining motion. I think the misconception is that some folks think a collar tie is restraining out ward thrust, once they get past that everything is hunky-dory.

A culvert is a collar that is with holding back the dirt. This is a collar in compression. Collars aren't just for restraining outward motion.

So is it still OK to call a collar tie a collar beam or the other way around, regardless of their color. Oh, and horses sometimes wear collars that are in compression, and they are pushing the load that is in back of them. Tim

I think it is helpful to refer to a piece in a frame depending on it's use. I also think it can be important to identify pieces designed to be in compression vs. tension since it can change the joinery (and engineering?). Ties are in tension. If a piece is not in tension, it should not be called a tie. Just to make things controversial, king-posts and queen-posts are designed to be in tension and thus should not be called posts!

Jim

In Discovering Timber-Framed Buildings the simple term collar is used with out the mention of tie or beam, just collar. If this member needs a color tie for the party it should be grey.

Hammer beam truss work uses the term collar. If the buttress or skimpy post fail the collar changes to a tension member?

Jim, if the tie beam on a king rod truss has a post or two under it is the king now a post? Tim

Tim:
If it's a rod it's a rod. Again, members are named based on their location. I don't believe that having other timbers under it has any effect on it's name.
Jim Rogers

Pendant isn't in wiki! But it must be that dangly thing under the tie beam, just under the joggle piece. (see wiki...king post). Tim