Compound Angle Sine Plate Jig

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Project by lew posted 08-25-2013 11:07 PM 3526 views 5 times favorited 14 comments Add to Favorites Watch

Our neighbor recently asked if I could make her a small chair for her daughter. The little one is going to be home schooled and she needs stuff for her study/work area. Without thinking, I said “Sure, I can do that”! Well hind sight is 20-20 and now I realize why chairs are not cheap!

The neighbor sent me a link to the type of chair she wanted- I was in trouble!! This chair wasn’t going to be 1x material screwed and glued together! Other than the seat and top rail, everything was turned and there is not one 90° angle on the entire piece. In fact almost every hole is drilled at a compound angle. Second problem- no plans!

So, where to start??

Fortunately, I have a very old child’s chair that belonged to my Dad. Unfortunately, it was much too small for the little girl. I figured I could use the old chair and scale up the dimensions and create a larger version. A little Internet research and some actual child measurements and I have the sizes I need to start.

But those dang compound angle holes are going to be a pain. For accuracy, I’d like to use the drill press for the holes. But, you know how hard you work to get the drill press table perfectly aligned and once there you hate to change it. Maybe there is a way to make a jig!

Her’s what I came up with…

The jig sets on the drill press table and pivots/tilts in 2 directions.

The new “table” can be raised or lowered via some piano hinge pieces left over from another project.

The assembly pivots on a large dowel (piece of turned maple) to add the “second” angle.

The tilted assembly and table are held/locked into place with plastic knobs and hardware

And the entire jig is bolted onto the drill press table.

I know what you are thinking- all that work for one chair. Maybe, but she has 2 daughters and lots of other home schooling friends. Just planning ahead.

Thanks for looking!

-- Lew- Time traveler. Purveyor of the Universe's finest custom rolling pins.

14 comments so far

View HillbillyShooter's profile


5811 posts in 2489 days

#1 posted 08-25-2013 11:18 PM

That’s one complex jig. You’ve really thought this through—nicely done.

-- John C. -- "Firearms are second only to the Constitution in importance; they are the peoples' liberty's teeth." George Washington

View jaykaypur's profile


4017 posts in 2605 days

#2 posted 08-25-2013 11:37 PM

Nice tool and a good design/build on it.

-- Use it up, Wear it out --------------- Make it do, Or do without!

View doubleDD's profile


7870 posts in 2240 days

#3 posted 08-25-2013 11:53 PM

Well built and thought out jig. Great job.

-- Dave, Downers Grove, Il. -------- When you run out of ideas, start building your dreams.

View grizzman's profile


7836 posts in 3500 days

#4 posted 08-26-2013 12:08 AM

well dang lew, ive had that same jig just sitting over in the corner of the shop, i could have sent it to you..:)...well at least you know how to make one now…so get busy and lets see the chair…oh…i have another corner in the shop, guess what is sitting there…::))

-- GRIZZMAN ...[''''']

View Karson's profile


35145 posts in 4597 days

#5 posted 08-26-2013 01:04 AM

Great Lew

-- I've been blessed with a father who liked to tinker in wood, and a wife who lets me tinker in wood. Appomattox Virginia †

View Roger's profile


20952 posts in 3001 days

#6 posted 08-26-2013 01:10 AM

Very cleavor indevor. Nicely engineered.

-- Roger from KY. Work/Play/Travel Safe. Keep your dust collector fed.

View waho6o9's profile


8516 posts in 2774 days

#7 posted 08-26-2013 01:51 AM

Very nice Lew, thanks for sharing!

View Michael Wilson's profile

Michael Wilson

588 posts in 2687 days

#8 posted 08-26-2013 02:35 AM

I’ve started with this idea no less than 4 times in the last few years, but was conveniently distracted at the hard part :-)

View CalgaryGeoff's profile


937 posts in 2679 days

#9 posted 08-26-2013 03:43 AM

That device on the drill press is one unique jig. The chair and desk must be great as well. Seems like woodworkers usually say yes to special request projects then figure out how to make them. Good work.

-- If you believe you can or can not do a thing, you are correct.

View SPalm's profile


5325 posts in 4079 days

#10 posted 08-26-2013 11:02 AM

I open my big mouth too many times also. Oh well, all good in the end.
The jig thingy looks great, now on to using it.


-- -- I'm no rocket surgeon

View MShort's profile


1797 posts in 3615 days

#11 posted 08-26-2013 12:46 PM

Looks like you were determined to make it work. Nice jig setup.

-- Mike, Missouri --- “A positive life can not happen with a negative mind.” ---

View RichCMD's profile


401 posts in 2138 days

#12 posted 08-26-2013 02:12 PM

Very cleverly done.

-- Ride the bevel!

View lew's profile


12422 posts in 3952 days

#13 posted 08-27-2013 03:34 AM

Thanks everyone for the kind words. And, yes, she has asked for another chair!

-- Lew- Time traveler. Purveyor of the Universe's finest custom rolling pins.

View Jim Bertelson's profile

Jim Bertelson

4250 posts in 3361 days

#14 posted 08-27-2013 06:12 AM

I will tuck this in my bonnet for future needs….......good solution. Still on my cruise, but will be home this weekend. Itching to finish some stuff in the shop….......

-- Jim, Anchorage Alaska

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