Sliding T-bevel, marking guage

[Bill]

1. A sliding T-bevel seems like it would be a useful markup tool. Any special reason they put a potentially blood-letting 45 degree point on the tail end of the blade (to help make it a combination square?)?

1. I bought a (wheel) marking guage recently, but now it seems to me that a "mortise and marking guage" would be generally more useful. Can you think of any reason I might want to keep the first rather than just "upgrade" to the second? Is the wheel marking guage more helpful in marking the part of the mortise or tenon that goes contrary to the grain than the other marking guage would be?

Bill

[Chris Friesen]

Good question....I've got no clue. Shinwa makes some reasonably priced ones:

?c=1&p=32594&cat=1,42936,50298,43508> 2. I bought a (wheel) marking guage recently, but now it seems to me that a

The mortise gauge (with two blades) is actually often more useful when marking the tenon than the mortise. If making the mortise the same thickness as your tooling, you really only need to mark one side.

Depending on the wheel gauge, you may be able to purchase additional heads for marking mortises. This is the case for the Vertias and the Tite-Mark, for instance.

It's worth having a mortise gauge, but if I were you I wouldn't get rid of the other one--it's often useful to have multiple gauges set to different measurements in case you need to go back and mark something that you forgot about the first time.

Chris

[Bill]

To me, a beginner, it seems that marking the tenon from alternate sides of the end of a beam using a single-bladed guage would yield better results than try to center a double-bladed guage by hand.

I think those that use the double-bladed mortise guage adjust the guage off of the cut tenon, and it seems that this would give a little more control than marking directly from the tenon itself. Because, for instance, you might cut the mortise just a wee-bit smaller for a snug fit.

Please correct me (anyone) where appropriate!

Best, Bill

[Bill]

(ONTO the end of the beam)

using a single-bladed guage would yield better

[CW]

Any error is then doubled.

[Chris Friesen]

Especially when working with hand-dressed lumber, your stock may not all be exactly the same thickness. By referencing all measurements from the show side of the stock, the exact stock thickness doesn't matter. The show side will be exactly as planned and the back side can be either left as-is or flushed up as appropriate.

Typically you would set the gap between the knives of the mortise gauge from the tool used to cut the mortise, be that a router bit, hollow chisel, mortise chisel, etc. The fence is then set to locate the tenon on the thickness of the stock.

For the mortise, you can use the same gauge if the members are the same thickness (door frame) or a separate gauge if they're not (table legs and aprons).

Chris

[Bill]

Not the error in the measurement of the shoulder width, and this way the tenon would be more likely to be centered. At least, that's the way I thought about it. How do you prefer to think about it--by calculating the tenon width in advance and then trying to mark the lines about the center by eye, or do you use a measuring rule?

Best, Bill

[Lew Hodgett]

RE: T-Bevel

Don't leave home without one, especially if you want to work on a boat.

RE: Tenons

They are why table saws exist.

Lew

[CW]

That would give you uniform shoulders but, if the tennon doesn't fit, what difference are uniform shoulders going to do you? Marking from both sides of the stock will work if your wood is exactly the same size (unlikely if dressed by hand) and you hold your gage just perfect. You will have far better results with this (and everything you make), if you pick a side and work from there.

[Bill]

Thank you for a good lesson!

Bill

CW wrote:

[Lew Hodgett]

------------------------------------- Pretty decent justification for a planer IMHO.

Lew

[Chris Friesen]

Until you get that gorgeous piece of wood that's just wider than your planer...and you want to keep it full width.

It never hurts to know how to do things by hand, even if you rarely need to use the knowledge.

Chris

[Lew Hodgett]

-------------------------------- I don't trust boards that wide not to cup.

Much prefer glue ups of narrower (6" max) boards.

Lew

[Bill]

Do you alternative their "cup direction"?

[Jeff Gorman]

The accepted drill goes as follows:

Nominate a face of each piece as the datum face (Face side) and an edge at right angles to it as the Face Edge. Mark with an 'l' type mark with the bottom of the ell shooting off towards the face edge. Mark the face edge with a vee that joins the bottom of the ell.

Always work the gauge's stock on the face side.

Set the gauge points to the size of the tool making the mortise. Actually with the tool just resting between the point at their very very tips. This ensures a very slightly wider tenon.

To get the joint central to the workpiece, estimate the setting of the stock, with the gauge against the face side make two dents.

With the stock on the opposite face make dents alongside the others.

Reset the stock so that the points fit exactly between the pairs of dents.

Repeat if necessary.

Good luck,

Jeff

[Bill]

Thank you for going into such detail. If I understand what you've written correctly, it will work great if the two pieces of stock to be joined are the same size/width.

Also, the "one marked line" version described earlier may give superior results if the two pieces to be joined are not the same size/width.

Bill

[Bill]

In case anyone else is interested in this discussion, here is a link to a fine YouTube video on cutting a mortise and tenon joint by hand:

[Larry Jaques]

On Wed, 27 Jan 2010 04:14:49 -0500, the infamous "Bill" scrawled the following:

--snip--

for the video. I wish he'd been more professional about it.

1) He cut down into the shoulders of the tenon piece several times as he quickly hacked off the excess. 2) He didn't pad the mortise piece from the clamp, so it was sure to have a dent where it was clamped down. 3) And did you notice the gapers he left as he fit the tenon into the mortise? At 5:44 into the film, the gap shown is roughly 3/16". The mortise is longer than it should be, reducing the strength of the joint.

[Bill]

You have a good eye:

Should he have just been "more careful" to stop on the line?

Not only is it longer, but it looks wider too. Is this an error, or is cutting it a little wide unavoidable? At the beginning of the video he points out that the difference between a good fit and a poor fit can be measured in thousandths of an inch. Did he fail his test?

Bill

[Larry Jaques]

On Wed, 27 Jan 2010 12:40:19 -0500, the infamous "Bill" scrawled the following:

Yes.

Width is 1/3-1/2 the stock thickness. I think you're mistaking depth for length. By length, I mean the long dimension of the rectangular mortise hole. Yes, it's an error if you don't make the hole the same size as the pole. ;)

He sure did. I know it was made for teaching, but a professional (like Frank Klausz in his M&T video) does a bit better, showing only what the student -should- see.