Making deep mortises

[Kevin]

Hi all,

I'm making a large mission-style mirror frame. The sides are 6" wide and will be mortised to receive tenoned 3.5" rails. I'd like to make pinned tenons and in order for the pin to be located near-ish the center of the side piece, I'll need to cut pretty deep mortises (2-3 inches). The mortises will be 3/8" wide. What is the best way to cut these mortises? I have a plunge router, but I don't know if there are bits that can go this deep. Drill out most with a forstner bit in my drill press, then clean up with a chisel?

Thanks!

Kevin

[Lowell Holmes]

I would consider marking the limits of the mortises on both faces with a knife and mortise each face with a plunge router 1" deep. Then clean up the middle with a forstner bit and a chisel.

I am just as likely starting the mortises with a chisel on both faces to define the mortises and then drill out the rest.

A couple of practice joints would be appropriate anyway.

Chris Schwarz has a good article in the current Woodworking magazine on the subject. It is worth a read.

In a previous issue, they did a craftsman mirror you might want check out. You can get the articles on line.

[John Grossbohlin]

Since the tenons are not through tenons I think I'd stick with a mortise of maybe an 1 1/2 to 2 inches, rely on the glue, and use decorative pins. This rather than try to do blind mortises 4 inches deep (1/2 of 6" plus an inch so the pin has something to pass through). The forstner bit should suffice for this task.

John

[Swingman]

"Kevin" wrote

Be aware that mortise and tenon joinery has some rather specific, time tested dimensions for best strength/results over the life of the piece.

Considering that the traditional depth of a stopped mortise for maximum strength is 3/4 the width of the leg/stile, it is unlikely that even an "end mill" used in your plunge router (available in much longer lengths than router bits) will be able to get you to that depth (4 1/2" in your case).

IME cutting lots of mortises, your best be in this instance is your last sentence above. Cleaning up drilled holes, with a good sharp mortise chisel made for the task, is not difficult at that depth, and it will have the added benefit of giving the authentic dimensions of the placement of your pins.

[SonomaProducts.com]

You can just do a standard depth mortise and then do any of the following.

- Set the pin on the visible face offset toward the seam of the joint. Actually very common in Stickley, Greene and Green, etc.

- Set the pin from the rear face so you get the strength of the pin 50 years from now when the glue has failed.

- > Hi all,

[C & S]

Your application does not require any serious strength Glue is more than enough.

That, or pin closer to the side of the stile. It would look more traditional that way.

-Steve

[Kevin]

Thanks for all the good advice! I'm going to try a less-deep mortise and just offset the pin closer to the inside of the stile. After checking out the Stickley piece and also the mirror in Woodworking magazine, I think I actually like that look better than the design I had first imagined.

Thanks again!

[spaco]

Maybe this is the long way around, but couldn't you make up the sides from 3 pieces of thin stock, gluing them together, while leaving out material where you want the mortises to be?

Pete Stanaitis

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Kev> Hi all,