Router Jig Design - Input/

[alex grams]

I am looking at making an adjustble jig for mortises/flattening spots for joints on round table legs, and would appreciate any input on the design.

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Several things I tried to accomplish
-Adjustable length: the top rails can be removed/changed in length.
-Adjustable height: The sides move up and down. I think though I am going to make a runner/key that is secured to one board and is maybe 1/2"x1/4" and runs in a dado on the other, that way vertical movement is guided and keeps the pieces aligned to one another
-The top is just a frame I can mount templates on the top for the router, depending on what type of cutting I am doing
-I can insert the jig onto the table without disassembling the spindle.
-For height adjustment, they only need to be rough, as the router bit travel will cover any fine tuning. I figure I can just cut blocks of rough height (1",2",3", etc) that I can put between the base and the bottom of the side boards to easily set them at a consistant height and parallel to the spindle.
-The base is keyed to slot into the width of the bed, with a piece of 1/4" metal (alum/steel) that will be pulled up snug to the T-Groove from the bed to secure the pieces from moving.

Any input/thoughts would be appreciated. I hope to make this adjustable to suit any needs in the future, but I haven't used a jig like this much, so it is tough for me to tell if there are any applications I may need it for that my design won't accommodate.

Thanks in advance.

[Dennis Ford]

That looks like it will work great, my only suggestion would be to beef up the diagonal bracing.

By making the top rails profiled; you may be able to flute pieces with shallow curves along their length.

[alex grams]

Thanks dennis, that is about my only concern too, stiffness on the verticals. I think I may do something more robust on the angle brackets. I may consider at the tailstock and headstock side putting a spanner than runs between the two vericals of the lower unit for stiffness, but haven't decided yet.

If the piece is long enough, I may consider making a middle section depending if sag becomes an issue.

[Dan Carroll]

Adjustable stops along the rails to allow for very fine adjustments in the travel of the router. Also something to keep the router from raising up as to cut. If you have a flat, square router base, have it ride in groves. I had a problem with the router wanting to jump to the side and/or rise up when I was router sliding dove tails for spider leg tables.

[Quinn McCarthy]

Alex,

I built a jig just like it for a porter cable plunge router. If you are interested I can post some pictures tonight.

Quinn

[Thom Sturgill]

I built a one-time jig for cutting a mortice for a table spindle. Here's a suggestion:

At both ends, make an open box the size of the throw of your lathe with a hole in the end about 2" diameter to allow the spur or live center free movement.
Attach a piece that fits between the ways to the center of one side on each box. Drill holes to pass a bolt through to a plate below the ways to fasten the boxes in place.
Slot the sides of the box so that your 'rails' can attach and move up and down. The slot only needs to go down to 1" above center. The tops (opposite the side with the mounting bracket described above) of the open box can be cut back to allow the router better access and a spindle extender can be used to allow the router to better access the top of the spindle.

For long spindles create a third frame with corners braced and use a pair of moveable blocks that supports the rails. Route down to it for each flute, move the center support over the area already fluted so that it is out of the way but still supporting and finish the routing.

Since mine was a one time jig, I sized the height of the box to the job at hand with a solid upper platform that I routed out as a template and clamped the assembly to the lathe with a pair of bar clamps. The assembly took less time than typing this response out.

[alex grams]

thanks for all of the input guys. Any pictures would certainly be appreciated.

[Quinn McCarthy]

Alex,

Here is he jig I made for mortising table bases. It is used with the indexing head on the lathe and bolts between the way. The routers bases are made from acrylic plastic. To use the punge router I made a base that rides on the very top of the jig with guides to run on the outside of the plywood sides.



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Hope that helps.

Quinn

[alex grams]

Well, I got my jig made up, and it worked pretty well. I have a 'slight' racking on it if i lean on it very hard (maybe 1/32" with a couple pounds side force) but it works pretty well. I made the main runners removable so I can adjust for a longer piece if need be, but I was very happy with it overall.

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