Is Powermatic Mortiser Easier to Cut with???

[charlie b]

Sorry about not responding sooner - still trying to come up with an illustration of some examples. An integrated chair leg/ chair back is an example. With the feet of the chair outside the outline of the front and the back of the chair seat, the mortises need to be angled

| | / +------+ / \ +----------+ / \

The ASCII diagram below, though the angles are too extreme, shows a rear leg part being mortised before being shaped on the bandsaw.

Mortising Chisel & Bit / / / / / / / / +--------------+-+------------+-+---------------------+ | | +-----------------------------------------------------+ chair leg chair back bottom

Make sense? Trying to convey 3-D info in 2-D when angles other than 90 degrees gets tricky.

charlie b

[Doug Miller]

[snip]

Hey, no problem -- thanks for responding. If you hadn't, I'd still be wondering.

Ahh, now I see the cause of the confusion -- we are picturing two entirely different types of chairs. Your picture is of a chair with non-vertical legs, having the same horizontal separation between the left and right sides at both front and rear. *My* picture is of a chair with *vertical* legs, having a wider horizontal separation between the front legs and the rear legs, e.g.

Side View Top View

| +-------+ back | / \ | / \ | / \

+---------+ +---------------+ front | | | | | | | |

I understand clearly how the tilting-head mortiser can cut the angled mortises needed for your picture of a chair. But how on earth can it cut the angled mortises needed in *my* picture, unless the fence and leg can be pivoted 90 degrees?

-- Doug Miller (alphageek at milmac dot com)

How come we choose from just two people to run for president and 50 for Miss America?

[charlie b]

snip

So many ways to use M&T joinery and so many ways to do them. If you combine the chair example I did with the one you did things really get harry and things get really interesting. A horizontal boring/mortiser machine can do a bit more than either a fixed or tilting head chisel and bit mortiser. Add the jig described by the url below and you can cut mortises at almost any angle or compound angle. A guy in the Yahoo Robland X31 group came up with this slick jig. With its two T-slots you can cut just about any angle on any axis, assuming your mortiser has the throw and the bit long enough.

The horizontal boring/mortiser is the fifth function on the Robland X31. The pictures on the lower half of the following page shws the XYZ table and the bit in the chuck on the end of the joiner/jointer - planer cutter head.

Between roof rafters and chairs the old high school trig class finally starts coming in handy. Sometimes I even use the analytical geometry I learned in college. Now calculas and differntial equations ...

Fun and intersting this woodworking thing.

charlie b

[Doug Miller]

[snip ascii art]

Thanks for the great links, Charlie!!

-- Doug Miller (alphageek at milmac dot com)

How come we choose from just two people to run for president and 50 for Miss America?