Checking joint sides

[Jim_Rogers]

Yesterday, I traveled to the Hancock Shaker village to visit with some students taking a workshop with Jack Sobon.

I snapped with method he uses to check the sides of a tying joist tenon's mortise in the long sill:



 

He is using his framing square against the sill (which is rolled on it's outside face, known as the adjacent face) to check with a combination square the sides of the tying joist mortise to see if they are parallel to the reference face surface.

Every time I visit with him I seem to pick up a tip for us all.

Jim Rogers

[jimdad07]

Seems that man would be well worth getting to know.  I read one of his books and he has a very clear way of explaining things.  You are fortunate to know him.

[logman]

Maybe I'm missing something here but as long as the timber faces are square can't you just use the comb square on the top face to check the mortise for square?

[Jim_Rogers]

Maybe I'm missing something here but as long as the timber faces are square can't you just use the comb square on the top face to check the mortise for square?

Sometimes the faces aren't square but the joints need to be true to the square face. This is how you check a mortise side to a non reference face side.

Jim Rogers

[Rait]

Hello. I have a question how to check for check for mortise/tenon joint sides if i do not have reference face (using snap line square rule). Timber Framing Fundamentals page 138 shows a jig to hold squares to the snapline but i havent been able to find a place to buy such. All i'v come up is to use stair gauges to fix the squares, (try to) hold both squares to same measurement at snapline (on both sides of timber) and then use combination square like it's shown here. However this seems to be better suited for three hand and 4 eyed persons which i am not, is there a better way to do it?



 

I am sorry for bumping up an old thread.

[klpauba]

I bet two "Squaremate Adjustable Clamp Fixture and Multiple Square Tool" (Amazon title) could do that.  I bought two of these (for $14 ea + shipping) for tenon/mortise checking (but it has many more uses).  There's a video on youtube on how to use it (just search for "squaremate").

Use the squaremate to join the two squares, let them set on the horizontal surface and clamp a piece of wood on either side at the same measure while lining them up with the chalk line.  Then figure out some way to keep it there!

[Ljohnsaw]

I am sorry for bumping up an old thread.

No, this is great!  That tip from Jim is great - hadn't seen that before.

[Rait]

clamp a piece of wood on either side at the same measure while lining them up with the chalk line.  Then figure out some way to keep it there!

My side faces are not parallel (and have curve to them), thats where the tip pointy things from the book woulde come handy - squares could be registrered straight to line and not rely on the face at all.

[tburch]

The jig looks like its using trammel points.

[Jim_Rogers]

The jig looks like its using trammel points.

Could be...
Jim Rogers

[klpauba]

Yes, I meant using some wood pointy things instead of the "trammel points" (although @tburch's thought of using them would work even better).