Long Stopped Mortise… How to make?

[photog]

Long Stopped Mortise… How to make?

Greetings,
I’ve never done one of these before but have an idea, so I’d like to solicit the forum’s advice to confirm or deny.

I need to plow a 3/8” wide x 3/8” deep x 47” long mortise into the middle of 1 ½” square dresser legs. These grooves will accept the rabbeted edges of the dresser’s side panels.

I’ve discounted the use of the table saw and dado blades. I have a mortising machine, but making a 47” long groove with that doesn’t make sense.

My thought is to use the router table, it’s fence and start and stop blocks. Lower the braced and supported piece into the spinning bit, plow down to the stop block then shut down and lift off the piece.

I think the 3/8” depth is shallow enough to do it in a singe pass. I’d clean up the rounded ends of the mortise with chisel or mortising machine.

I’ve done edge treatment in the middle of legs using this technique before with success, but never buried a straight bit into a blind cut in middle.

Lowering into spinning bits or blade always gives me some anxiety. Better method anyone?

 

[zinfella]

The photo galleries are down, or I would show one method. I used my Festool rail and Festool OF 1400 router to make mortises. Using that method, the length was not an issue, as I just set stops at each end of the mortise and let the guide rail do it's thing.

 

[DaveO]

Router, edge guide and 3/8" upcut spiral router bit. Clamp some straight stock to each side of the leg to provide more width for the router to ride on and give a paraelle straight edge to guide the routers edge guide. Make your stop and start lines. Plunge in and router away, you should be able to do it in one pass.
Like what we did in this thread, second pic down.
http://www.ncwoodworker.net/forums/showthread.php?t=7321

HTH, Dave

 

[Jim Murphy]

I think you've got the right idea.

I would make one suggestion: when you drop the stock down on the bit, be a little shy of your mark and gently climb cut back to just slightly shy of the mark. Stop that same hair shy at the other end. A chisel is much easier to control than 22,000 RPM of sharp steel.

 

[Monty]

I would do it using a hand held router with a good edge guide. If you can clamp two of the legs together without interfering with the edge guide, you would have more support to keep the router steady, and when you're finished routing one leg you can turn the router around and run the edge guide along the other leg.

 

[Travis Porter]

Router with edge guide and spiral bit as suggested. That way if there if the board isn't perfectly straight, the guide will follow the curve of the board.

 

[photog]

Thanks much to all who replied. You can be sure I'll try the technique on a prototype scrap leg first. I just wanted to get a feel for the idea before steering down that road.

photog

 

[Grgramps]

Dan, Since you have a router table, I think that's the obvious way for you to do this. With an adequately powered router you could do this in one pass. If you are not totally comfortable with this procedure, why not make it in 2 passes? Try 3/16" depth for the first pass and move your stock from left to right so the bit will push the work against the fence. I can understand your apprehension if you haven't done this before - I've had the feeling more than once.
Roy

 

[Joe Scharle]

I think most folks fear overshooting the stops so I suggest drilling a hole at your start/stop points (forstner bit works well here) then rout the rest.
But once you've used your edge guide as few times you will have the 'grip'.
Good luck

 

[cpowell]

I think most folks fear overshooting the stops so I suggest drilling a hole at your start/stop points (forstner bit works well here) then rout the rest.
But once you've used your edge guide as few times you will have the 'grip'.
Good luck

Beat me to the punch!! I make a start and stop hole with my mortiser, then use the hole to set the router fence and depth. When you hit the hole on the opposite end you're done.

Chuck

 

[Monty]

I just re-read this - if you're putting a panel in the leg, are you using mortise and tenon joinery? If so, cut the mortises first, then at the router table you can drop the bit over the first mortise and run it until to get into the mortise at the other end. No need for start/stop blocks or any anxiety.

 

[NCPete]

thanks Monty, that is what I was thinking would be the way to do it, only other, more knowledgeable guys than me chimed in first. Seems that is the way I have watched Norm do it.

 

[photog]

Monty,

Yes, the joinery is M&T and just as you say, at each end of, and falling within the long 3/8” deep groove there two 2 ¾” tall mortises that are an additional 3/8” deeper to receive the upper and lower side rail tenons. If I cut these first, zipping out the long groove between them will be a walk in the park. Thanks

 

[zinfella]

Since my pics are now available, here ya go.................I hope!

 

[photog]

I cut the mortises using the router table and fence with relative ease and safety. The grooves are true and straight with no burning. I don’t want it to be perceived that I’m ungrateful for the advice from those who recommended the guided handheld plunge router technique.

The conditions changed to make the router table my choice because I did not have to lower the pieces onto a live bit. The plans called for mortises to receive the top and bottom rail tenons, which are deeper, falling within and on each end of the long groove. It was suggested that I cut these first, which I did on my HF mortiser with x/y axis vise.

With the router off, I was able to set the fence and position the piece with the bit in this deeper mortise. I switched on with the bit only biting air in this void. I proceeded to route the blind cut until the bit exited into the deeper mortise at the other end. I made a reference mark so I would know when to expect the release of resistance as the bit entered the end mortise.

 

[Monty]

Good to know it worked out for you. Now you're obligated to show us the final product when you're done!