In my opinion, one of the most difficult joints to make is a miter joint. Although they are very attractive, they have almost no inherent strength, and require a high degree of accuracy to get all four corners of a box or frame to meet without gaps. To ensure that they remain closed, I use a spline of some design to strengthen the joint.
A number requested additional information on the Miter Spline Jig I use when making boxes. I can’t take credit for the design of this jig, but for the life of me, I can’t remember where I got the idea; perhaps a magazine or maybe a woodworking buddy.
It’s very simple in concept; a carrier that allows me to pass the mitered corner of a box or box lid over the table saw blade at 45 degrees. I think the close-up pictures speak for themselves. The jig is crudely made, but the right-angle is dead accurate. I’ve been using this for about four years. Perhaps someday I will make one that looks like it belongs in Shop Notes; NOT. LOL



Here I have just cut two spline slots in the four corners of the previously glued up box body. The blade is tilted to ten degrees and the box was flipped so that the slots angled in opposite directions. The splines will be cut from American Maple and will be one saw curf wide. I will also use American Maple to make the trays that will fit into the box – but that’s a few blogs away yet.

A close-up of the spline slots.

-- CanuckDon "I just love small wooden boxes!" http://www.hilsbiblechurch.org/






















17 comments so far
MsDebbieP
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14096 posts in 1039 days
posted 818 days ago
it looks so simple
-- ~ Debbie, Canada (http://www.execulink.com/~yohan)
Lee A. Jesberger
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3709 posts in 858 days
posted 818 days ago
Don;
From these angles, it’s easy to see. In the earlier photo, it looked like the box would be several inches from the saw table. Had me bewildered.
Thanks for posting this!
Lee
-- by Lee A. Jesberger http://www.prowoodworkingtips.com http://www.ezee-feed.com
TomFran
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2501 posts in 873 days
posted 818 days ago
Don,
Thanks a lot for your willingness to share your knowledge. The pictures are very helpful.
Isn’t it amazing that some of our jigs, although not very attactive, do an amazing job at their intended purpose?
-- Tom, Surfside Beach, SC - Romans 8:28
PanamaJack
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4447 posts in 956 days
posted 818 days ago
Great pictorial Don. Another great blog.
-- Carpe Lignum - Seize The Wood,
Thos. Angle
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4015 posts in 841 days
posted 818 days ago
Don, Thanks for sharing. Seems the first of these I saw was in R. J. DeChristophoro’s Book “The Complete Book of Power Tools” I see no reason that our jigs need to look like our furniture. They only need to be functional. Most I use once or twice and that’s it. Your box works very well and that is what you expect from it. Keep going with these boxes, Don, because I just happen to LIKE little wooden boxes alot too.
-- Thos. Angle
Joel Tille
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214 posts in 1123 days
posted 818 days ago
thanks for the closeups. This could be in shop notes, in the shop it’s all about fuctionality not the beauty, that is what should be the end product. Of which you have many great examples.
-- Joel Tille
mot
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4901 posts in 915 days
posted 811 days ago
Well, that clears that up! Thanks for the post Don! Great tutorial. (subliminal CSS plug being sent down under)
-- You can discover more about a person in an hour of play than in a year of conversation. (Plato)
Brad_Nailor
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1192 posts in 836 days
posted 800 days ago
Great jig. Who cares what it looks like..if it does what its supposed to do its awesome! I am going to build one just like it! I love miters and I like the splines for decorative more than structural purposes. I love the angled effect too..a little tweak that makes all the differance in the beauty of the finneshed piece!
-- David, South Windsor, CT "I love the smell of sawdust in the morning"
Hawgnutz
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522 posts in 955 days
posted 790 days ago
Very nice jig, Don. Looks better than soem of my jigs….LOL As long as they get eth job done, who is gonna look at em, anyways!
Gonna have to make me one, too.
God Bless,
Hawg
-- Saving barnwood from the scrapyards
Andy
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562 posts in 787 days
posted 779 days ago
Don, what type of blade do you use for cutting splines slots? I use a standard ATB saw blade which means the bottom of the kerf is not flat.I then use the edge of a file to clean them up. Tedious and not consistant results. I am thinking about getting a flat top grind ripping blade which will make a perfectly flat bottomed kerf.Whats your thoughts.Thanks in advance.
-- " If I can make it,so can you" Andy in Oregon
CharlieM1958
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7467 posts in 1097 days
posted 779 days ago
So many jigs…..so little time.
-- Charlie M. "Woodworking - patience = firewood"
CharlieM1958
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7467 posts in 1097 days
posted 779 days ago
BTW, this may be (read: probably is) a dumb question, but I noticed the spline cuts don’t seem to be perpendicular to the box side. Is this an appearance choice, or is that part of what adds extra strength to the joint?
-- Charlie M. "Woodworking - patience = firewood"
Don
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2590 posts in 1056 days
posted 779 days ago
Charlie, there are no dumb questions, only dumb answers. I hope this answer doesn’t sound too dumb.
It’s simply a design choice. I like the look, but my wife doesn’t. I can only hope that my client does.
-- CanuckDon "I just love small wooden boxes!" http://www.hilsbiblechurch.org/
Don
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2590 posts in 1056 days
posted 779 days ago
Quote Andy: ”Don, what type of blade do you use for cutting splines slots?”
Andy, I have the same problem. I use a very narrow and sharp chisel to flatten out the bottom of the slot.
I, too, find this less than fully satisfactory. I plan to purchase a cheap saw blade and have it ground flat for this purpose. It will only get occasional use, so I don’t think that I should be necessary to spend good money for the blade.
-- CanuckDon "I just love small wooden boxes!" http://www.hilsbiblechurch.org/
Krisztian
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89 posts in 778 days
posted 776 days ago
Very nice jig,Don.I need to make one,just like yours.
-- Krisztian VA My website: www.vacarpentry.com
Ethan
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751 posts in 1053 days
posted 776 days ago
If you can get to a home depot, the Ridgid 50 tooth combination blade sells for $29 and makes flat bottom cuts.
Popular Woodworking magazine listed it as one of the best buys for a saw blade earlier this year. It came in just under the really expensive WWII and Freud blades, but at a fraction of the cost.
-- Ethan, http://greystonegreen.blogspot.com/
Don
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2590 posts in 1056 days
posted 775 days ago
Ethan, thanks for the heads up. Out of the question for me, though. I live in OZ. LOL
-- CanuckDon "I just love small wooden boxes!" http://www.hilsbiblechurch.org/