Mortise through 3" hard wood?

[John TenEyck]

Gary,
Also, if you're having trouble lining up your router on both sides properly, then I've seen this done several times with a saddle-style jig that has templates on both sides of the piece that are locked in place by an adjoining saddle and keeps them perfectly lined up, so you don't have to move the jig when you flip.

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This. Then leave the radii in the corners and round over the edges of the tenons to match. It will make a miserable job most any other way pretty easy.

John

[Gary R Katz]

I'm not having much luck responding to each entry, but wow, what a wealth of ideas. I could quit the project and spend a few months trying each one only because you guys got my curiosity activated...Naugh, I don't think I'll do that. I almost built a saddle jig before I tried the other methods and I might go back to that idea.

[Mel Fulks]

Gary,you will find this is a great think tank ,don't worry about thanking us . Just let us know if any of these ideas actually work....and we'll try them.

[Silas Smith]

if you were closer i do it for you in minutes. My Stenner cuts though mortises 6" deep from one side with a single finger.

I'm taking my ball and going home now.

Seriously, I've never seen a Stenner in action before, absolutely awesome!

[Gary R Katz]

Thanks Mel, I'll let you know how it works out, maybe even post a pic. Thanks everyone for the great ideas, I learned a lot of new things.

[Shawn Pixley]

I did similar through mortises a couple of years ago on slightly harder wood. Eight through mortises and eight standard mortises. I used my table top mortiser for the entry and exit as deep as it could go. I did spend some time sharpening and polishing the bit/hollow chisel. I also has to stop and let it cool during the process. I then used sharp chisels to remove the rest and clean them up. There was a full day on the mortiser (with a fair amount of time waiting for the bit to cool). There was the better part of the second day cleaning and tuning with chisels. My sharpening improved as a result.

[Jim Matthews]

If they're through mortises, why not use a jigsaw with a good blade and an exit guide?

Start with a through hole large enough to pass the blade with some clearance.
Tack a batten to the outside edge of the mortise, on both shoulder sides.

On the opposite face, tack a batten that traps the "shoe" of your jigsaw so it can't twist.

You can also shave the shoulders with a blade if your jigsaw has a zero oscillation setting.
(Teeth facing the shoulder, the saw moved laterally along the shoulder wall.)

I use the Bosch line of blades, and they cut oak well.
I used them this way to cut a single mortise in Angelim Pedra which has a Janka rating of 3040.

I suspect that you're having alignment problems as the opposing faces aren't precisely parallel.

If you use the batten guide method, you're only referencing off one face, and guiding the blade at the exit.

[Chris Friesen]

I've had good luck with a drill press and a Forstner bit. Drill at each end initially, then at intervals in between, then go back and remove the waste centering the bit on the waste bits if there isn't enough wood left for a full "bite". Finish up by drilling every 1/8" or so and you'll have a decent mortise. If you like you can do a final cleanup with a chisel or float.

[Mark Bolton]

Oddly we are working on a large trestle table for a customer at the moment which has deep mortises (3. 5") in white oak.

We use the DP w/2 1/4" forstner to punch out three holes getting rid of most of it then a template with fences under, clamped, and router with straight bit for the cleanup. If your parts were good and square you could get clear through 3" this way if you had a big enough router.

https://picasaweb.google.com/lh/phot...eat=directlink

https://picasaweb.google.com/lh/phot...eat=directlink

[Danny Thompson]

A mortise float will work aggressively, is easier to control than a chisel, and reduces the risk of gouging the mortise wall. What I used on a similar project: http://www.lie-nielsen.com/joinery-f...ortise-floats/

[Michael Peet]

You can drill out most of it and clear the remainder with a chisel. Clamp a guide block right on the line. Of course the guide block must be square to the surface. Start with the cross grain ends first to prevent splitting.

P1020324.20.jpg

Mike

[Brett Robson]

I'd use a router to cut half of the mortise depth, then drill a 1/2" hole through the bottom of the mortise, flip the piece over and stick a bearing-guided flush trim bit through the hole and route out the other half. Square up the corners with a chisel and you're done.

[lowell holmes]

Great solution! I wish I had thought of it.

[Gary R Katz]

I've never seen floats before but they look like they might allow for more control than a chisel. I like that idea.

[Gary R Katz]

Hey Shawn, your post reminded me to check my chisel bits and yes, they need to be sharpened. I keep forgetting to check my tools for sharpness and with this hard oak I'm going to have to keep up on this. Sharpening should help since I could only shave a small amount at a time.