Chair rail mortise

[woody dixon]

I am attempting to build my first chair and need help on how to cut mortises of the bottom of the top rail and top of the bottom rail. The rail is curved and therefore there is no straight edge for a router or mortiser to register to. One way to do this would be to make a template and use a router with a bushing. That would be somewhat difficult since the mortises track the curve. In searching for answers I found references to how easy this would be with a horizontal mortiser but I can't visualize how that would work. Anyone ever do this with a horizontal mortiser or have any ideas on how to do this? Thanks.


Woody Dixon

[Davis Young]

This wouldn't be that easy with a horizontal mortiser because you would have to reposition the rail at each mortise and there would be way too many chances to introduce error. The template would be the better choice, with all the mortises for all the slats in one template. This way you only have to position the template once per rail and the mortises will stay relative to each other.

[John Lanciani]

One chair - by hand and eye (drill press then chisels for me)
100 chairs - cnc router

[Wayne Lomman]

The best approach is to machine the mortises and tenons before cutting the curves. If that isn't possible or it is too late, make a jig to hold the rails at the appropriate position for your preferred machine. Chairs go much better hand in hand with good jig making. Cheers

[woody dixon]

If I make a template, is there an easy way to make it since the mortises are on a curve. Using a plunge router to cut the slots in the template I have no edge for a guide and freehand seems inaccurate to me. Do I use a drill press to remove most of the waste and clean up the template with a rasp or file?

[Brian Holcombe]

I think may be helpful to post a picture of the part.

Judging by the context provided so far I would drill it then chop it square with a chisel.

[Joe Calhoon]

I ran into this making some chairs for myself. I just centered the mortise on the clamp and it seemed to work fine. Not sure if it would work the same on a horizontal mortiser.
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[David Eisenhauer]

This is one of the type things that pushed me to return to further exploring the hand tool work methodology that I started with 30 years + ago, then slowly replaced by machine working methodology over the years. Some times it is just easier, quicker and with quite acceptable results to just do it by hand rather than struggle to come up with a machine setup. Hand work is probably quite a bit more accurate than pure machine-work only folks realize. Your current project may not be the time/place that you wish to try some hand work out, but keep it in mind for the future.

[Wayne Lomman]

This sounds nuts, but if you want a jig to be good, make a jig to make the jig. What I mean is you need to set up some sort of guide to make your final accurate shape in the jig.

If I understand correctly, you want your mortise to be curved. That's easy but it means a matching tenon which is not so easy. The best solution is to divide the longer curved mortise into two or more narrower mortises as one should do with any wide mortise to keep some strength in the rail. This means you machine two or more straight slots instead of one longer curved slot. Cheers

[lowell holmes]

I learned to make chairs from Paul Sellers at Homestead Heritage back in the day.
We chopped the mortises by hand. I have made nine rocking chairs for family and
friends. I always chop the mortises by hand. You make a plywood pattern for the
mortises and draw the areas to be chopped out and just do it.

To see an image, google "Brazos Rocker". I sit in a chair daily that looks like the
the first chair that comes up. It is mesquite wood.

http://www.sustainlife.org/blogs/woodworking/brazos-rocking-chair/

[woody dixon]

Thats what I am trying to visualize. The mortises are not curved but are at an angle with straight sides. Enclosed is a picture. The middle mortises could be cut with an edge guide riding against the rail(I have not cut the curve yet) but the 2 mortises on either side are at different angles. What kind of a jig would accomplish this?364731

[Brian Holcombe]

Just drill and chop or just chop. Develops a bit of confidence with hand tools in addition to getting things like that done much quicker than would making a jig.

[Pat Barry]

Thats what I am trying to visualize. The mortises are not curved but are at an angle with straight sides. Enclosed is a picture. The middle mortises could be cut with an edge guide riding against the rail(I have not cut the curve yet) but the 2 mortises on either side are at different angles. What kind of a jig would accomplish this?364731
Without know what the vertical members actually look like or need to look like, I would suggest the possibility that these could be squared off and then simply done with a standard drill / mortice attachment. If they absolutely need to be rounded then I would go with a drill press and forstner bits to remove most of the waste and finish with chisel method.

[Keith Hankins]

The best approach is to machine the mortises and tenons before cutting the curves. If that isn't possible or it is too late, make a jig to hold the rails at the appropriate position for your preferred machine. Chairs go much better hand in hand with good jig making. Cheers

+1 what he said