Timber Framers Guild Forums Tools Tool Forum Its like a square, can't remember what its called

Metalwork - Ugh!

Big Als Mother is a Big Al with big feet. Dave Carlon has the only one I know of. It has a much larger base on it so you can use it with more accuracy on wany timbers.


Dave

I have a guy that can water jet metal....and can weld the wings back on a hummingbird...
So if this thing doesn't work right....I'll have one next week that does...LOL

all good carpenters are at least an occasional metal worker.

Dave:
I've seen Big Al's mother now that you mention it....
Jim

I know this is a five year old thread about the Big Al but a timber framer has asked me if these comments by Clark about the Big Al not being accurate are true.

Ok so here's what I did. I got out my Big Al and my regular framing square the one that I use for all my timber framing.

And I compared the 2" slot on the big Al to the 2" body of my framing square. And it was exactly the same. Next I compared the 1 1/2" tongue of the framing square and it was exactly the same.

The only thing I can say about Clark's comments is that one, he got a bad Big Al or two he got a bad framing square. Most likely it's the framing square.

Has anyone else checked their Big Al to their framing square and found a difference?

My Big Al was made by Al himself back in 2000. Are the new ones off?

Jim Rogers

Check the width of the slots on your big Al. They should be an inch wide. I put the blade of my Starrett combo square into the slots on both of mine, and it's sloppy. Maybe 1/32? I've gotten used to it, and know how to compensate for it. CB.

IIRC the slots are wide by a fraction to account for pencil thickness... sort of remember someone telling me that when I bought one at a Heartwood workshop way back in 200?...

Dave, we unscrewed the base and added wide aluminum 3" angle stock as its replacement. Yup, silly wane, fixed it right up.

I just checked my Big Al and yes my 1" framing square tongue is sloppy in the slots between the bars.

But I guess it comes down to a question of accuracy or tolerance. How accurate does it need to be?

If the tenon is laid out 1 1/2" off the reference face and then 1 1/2" thick using a Big Al. And the mortise is laid out 1 1/2" off the reference face and then 1 1/2" wide with the same Big Al aren't they the same?

If they are both off the same 1/32" more or less, does it matter?

They should both line up and go together, with the faces flush to each other. At least that's my opinion, that they should.

And I have just tested two timbers, here and now. One is a 3x5 brace with the 1 1/2" layout of the tenon. And the other is a 6x8 tie beam and it's mortise is 1 1/2" off the reference face and 1 1/2" wide both laid out by the same Big Al. And when put together the reference face of both timbers are flush.

My point is if you use the same layout tool for both joints and they are both off by 1/32" or so, it shouldn't matter.

Jim Rogers