difficult cut-advice please

[rdewinter]

I need to make an accurate cut on the end of a 1 1/2"x2"x24" piece of popular. The cut is what I will call a saddle which fits over a tenon. The cut is about 1" wide x1 1/2" deep. To clarify see picture below.
Sounds easy, huh? But I need square sides so the saddle fits over the tenon and this saddled tenon fits square and tight into a 3/8" groove in an adjoining piece. Incidentally, this configuration forms the base of a tilting table for my laptop.

The cut!! Cut it like a tenon with a tenon jig? If so, how do you stabilize the 24" vertical piece? Band saw or sabre saw? Don't think so, not accurate enough. Even thought about laying piece flat on the ss, but can't get a flat bottom. How about securing the piece to a sacrificial fence in the mitre gauge? Secure it somehow in a sliding table?

Suggestions welcome.

[wa2crk]

Hi;
Could you clamp some pieces of scrap to the work piece to provide a stable base for a router and use the router and a guide fence to make the cut?
I know that the router will leave round corners but they can be chisled square and as long as the visible parts are good the part not seen can be less than perfect.
Bill

[charlese]

Good Morning, RD! Right now I am thinking of several ways to make this cut, so I'll just start rambling on. Maybe a method that makes sense to you will appear.

If you think of the cut as a thru mortise rather than a saddle, a 1" drill bit would be a good way to hog out most of the wood. Trim with a chisel.

You could clamp the piece vertically to a mortising jig then using a saw blade, or a dado blade (set to a smaller width) make multiple passes to remove most of the wood. Again clean up with a chisel.

You could use the horizontal boring mode of the Mark V with a SS router chuck and the miter gauge to make multiple passes for both depth and height. This could be very accurate if you use the adjustable stop ring.

I see you have a sliding crosscut sled. You could use this along with the horizontal boring/router mode, instead of the miter gauge.

Got to get into the shop now, will check back later.

P.S. If you choose to use the horizontal boring position - You could clamp the work piece to your sled and clamp the sled to the table, then rout your saddle vertically, rather than horizontically

[brown_hawk]

Use the SS as a giant jig.

Start by raising your SS saw blade as high as it will go, leaving the front as close to vertical as it can be. Move the quill as far to the left as the table will let you. Set the fence up with the proper distance for each side of the saddle, and a stop block. Make sure that the stop block is measured from where the front of the blade comes through the table, or a little short. Use the far side lock to make sure you cannot extend the quill beyond that point by accident. With all of that setup done, release the quill and let the blade go back.

After releasing the quill, and with proper support for the length, 1) run the piece into the saw to the stop block. 2) Flip the piece and repeat. Move the quill closer to the fence. Repeat 1 and 2. Repeat as necessary. This will allow you to make sure the last cut on each side is right on. The bottom part of the cut will have the waste removed, and you can try the saddle on the tenon to assure a perfect width. Clean out with a chisel, or even move the fence to remove more before you chisel out the remainder.

Take plenty of time with the setup, and the rest will go easy.

Hawk

ETA: I did a cut like this once, and working from the middle of the cut out gave me more confidence than trying to both cut on the line and make sure of the correct depth in one cut. You might want to sneak up on the depth also.

Also, with the blade that high, make doubly sure that the guards are in place. Even if you have to rest the guard on top of the fence.

For the stop block, if you don't have one that attaches to the fence, make a sacrificial fence, and a stop block with a slot in it. Flat head screw and washer through the stop block into the sac. fence. The slot will allow adjustment of the stop block.

Hawk

[dusty]

I would cut the left and right cheeks like a tenon (using the tenon master). The 24" piece sricking straight up is not too hard to handle. Then I would hog out the center with repetitive passes, adjusting either the tenon master for each one or using the quill.

Clean out the bottom with a sharp chisel.

The same thing could be done on the bandsaw but I prefer the table saw and tenon master.


It could also be done by drilling out the center and cleaning up the cheeks and bottom with a chisel.

I still prefer the tenon master and table saw.

[easterngray]

Build a jig that fits over the fence from three pieces of MDF. The piece that rides against the front of the fence facing the blade is cut from stock wide enough that you can cut a tall post in it's center. In other words, cut it from twelve inch stock and make the center post rise to the full width of the stock. C-clamp your 24" piece to be mortised at both the bottom and the top of the post. That should be plenty stable to get a square cut. Use a dado blade and cut away. Alec

PS - WAIT A MINUTE!! Couldn't you just use the hollow chisel mortising attachment in drill press mode for this cut?

[dusty]

If you have a Tenon Master, I think that is the way to go.

Using a saw blade:

Set the depth of cut, I think you said that would be 1 1/2".

Set the face of the tenon master the required distance away from the blade (1/2"). You said the stock was 2" wide and the cut would be 1" wide. This would leave 1/2" on either side. Cut one cheek, rotate the stock in the tenon master 180 degrees, cut the other cheek.

All of the stock between the two cuts must be removed.

Using a dado blade:

If you use a dado blade, set it for a tad over 1/2" wide. Set depth of cut for about a 1/4" to start and then sneek up on the depth (1 1/2"). Set the depth back to 1/4". Rotate the stock in the tenon master. Sneek up on the depth of cut.

Using the dado would be my choice.

[sandyj]

Think Differently - use a handsaw & chisel - work inside the pencil marks.
Regards
Sandy

[Nick]

I like Sandy's suggestion -- think differently. You don't have to make this piece by sawing/routing/dado-cutting a single board. You can achieve the shape you're after simply by gluing three boards together.

If you've already cut the boards , are committed to create the saddle joint in them, and you don't have a tenon jig, then make one. They are ridiculously easy to build -- there are dozens of designs for them in my books alone and a buh-zillion more out on the 'net. I have one that I use with the tall fence that I showed last weekend on Sawdust Session #18 that is just two pieces of wood -- a 3/4" x 10" x 10" scrap of plwood and a 3/4" x 1-1/2" x 10" scrap of hardwood glued to the plywood. I butt the work up against the hardwood, clamp it to the plywood with a small hand screw, and push it along the tall fence and over the blade. This or any other well-designed tenoning jig will hold the stock vertically just fine.

With all good wishes,

[rdewinter]

Good suggestions all. Thank you--you guys are creative thinkers and obviously good craftsmen as well.

I think Nick's suggestion rings clearest. Think differently or at least think further ahead. I am blindly following a plan. A little different glue up and/or milling of the stock would have provided an accurate and square saddle with less possibility of error. Thanks Nick--your forcing me to think and plan ahead; which, by the way, is one of the reasons I like woodworking.

Charlese--your horizontal ss mode with router chuck and mitre gauge sounds intriguing but I don't understand the method.

Easterngray--I like your hollow mortising chisel idea. Just clean up with a sharp chisel. One problem-don't have that accessory. Darn!

Dusty--tenon jig is probably the best idea since I have the pieces milled. I built a tenon jig but will have to alter it to make the fence higher as it is only 10" tall now and it's a couple of degrees off (hazard of home made jigs)

I'll post a picture of my final joint and share my methodology.

Thanks again,
Bob
San Diego