# Splines for strength on a mitred jewelry box. Do I really need 'em?



## Babieca (Apr 13, 2014)

I'm making mitered a jewelry box out of 1/2 inch walnut.

I was planning to put maple splines in it (the top and drawer dividers will be curly maple). Now that the box is glued up, I really like the clean look of it without splines.

The end grain miters are getting a little bit of an internal spline from 1/4 inch plywood that is serving as the box bottom/ drawer runner. It is glued into 1/4 deep dadoes at each mitered joint. (After the fact I realized that I should have done stopped dadoes for the drawer runners. Oh well. That's what learning looks like)

I don't expect these joints to take a beating. For this kind of application, do I really need the added strength of the splines?

Thanks for your input!


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## jmartel (Jul 6, 2012)

No, you don't. They do add strength, but a jewelry box is a low stress application. The splines are merely decorative.


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## wapakfred (Jul 29, 2011)

It doesn't take much to knock apart an unreinforced miter joint,but if you glued those bottoms in, that should be enough.


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## rad457 (Jun 15, 2013)

I don't know! fill that box full of GOLD and she may burst! LOL!


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## jmartel (Jul 6, 2012)

> It doesn t take much to knock apart an unreinforced miter joint,but if you glued those bottoms in, that should be enough.
> 
> - Fred Hargis


A miter joint is 3x as strong as a butt joint. Check out the FWW test.

http://paul-flores.com/downloads/Joinery_Failure.pdf


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## levan (Mar 30, 2010)

If you want a clean look but still want to use splines for strength you can hide the spline vertically inside the miter before glue up. I would go ahead and put horizontals in this one for the added strength. 
best wishes 
Lynn


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## jdh122 (Sep 8, 2010)

Take a look at the beautiful boxes made by BritBoxmaker using his ez-miter technique. un-reinforced miters, and as far as I know they don't fail. I think it should be fine.


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## a1Jim (Aug 9, 2008)

Miters basically are butt joints which are not as strong as other joints the link above points out that it in the test on was surprisingly strong. I don't think that is the norm.Butt joints with all end grain just don't have the strength that other joints have. Do you have to spline a miter in a small box ? No but in my thought it's a good idea .

Here's a quote from the above link.

" Though the miter was surprisingly strong, structural limitations
make it hard to recommend the unreinforced miter for furniture making
tasks. When assembled, the joint is angled at the typical
45°. However, as wood expands and contracts over time, the 45°
geometry will change (see drawing, below), causing joint failure "


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## CharlieM1958 (Nov 7, 2006)

I only use splines when I want them for appearances. I don't think they are necessary at all for decorative boxes.


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## shipwright (Sep 27, 2010)

Not necessary. I've done some destructive testing myself using hot hide glue on good fitting miter joints and if anyone puts as much force as it took to break them on a jewellery box they shouldn't own nice things. That said if you want, for your own peace of mind, to reinforce them… vertical splines as mentioned above will get the job (over)done for you.
Just my opinion of course.


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## Neptuno (Oct 17, 2014)

I don't think you need anything, if the joint is neat and tight. Mitered joints like that do not really classify as endgrain joints, as the 45º angle makes for a, lets say, half endgrain only. Be sure to size the 45º miters with diluted glue before the final glue-up, for much added strength, thus guaranteeing that the joint will not starve.

Adding vertical splines, or biscuits of that matter, would facilitate aligning the glue-up, specially if you are doing many boxes.

Pedro


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## timbertailor (Jul 2, 2014)

No. With today's glues, the wood will split before the joint gives way.

Just consider them decoration.

P.S. Very diplomatically said, Paul.


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## a1Jim (Aug 9, 2008)

Babieca
Obviously many folks commenting here make more boxes than I do and much more involved boxes too.. I'm a person who over kills most of my construction so it may not be necessary for you to do the same as I do.
End grain is end grain no matter what angle it is cut at. I do agree with that sizing of the end grain will add to is strength .I think the best way for you to resolve this for yourself is by gluing up a test miter for yourself and do your own strength test,to see what you think.


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## Babieca (Apr 13, 2014)

Thanks for all your thoughts.

I'm going to leave them out. If this leads to catastrophic (or even minor) failure, I'll update. For future boxes I may go the vertical spline route.


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## OldEd (Dec 26, 2013)

I do believe that the strength, or lack of same, depends on the wood. As was pointed out above, modern glues are very strong. "Properly glued" joints are strong - I've made end-to-end joints which have held up for the past ten years. HOWEVER - I was using a very dense wood: don't know what it was, I got it as a gift from a friend of a friend, who brought back a few bf from somewhere in S. America.

I've also done it with pine - you have to prepare the material by soaking the end grain of both pieces in thinned glue so that it soaks it up and thus you don't get a glue-starved joint, as was also pointed out above.

True, splines will add strength, but in small things, such as jewelry boxes, they can be a real pain to put in. And a correctly glued joint should withstand most normal stresses.

So go with it…


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## bannerpond1 (Mar 15, 2013)

Splines are one more step in the process, but I have decided they're worth it in ease of glue-up in making the miters fit perfectly with less clamping. The peace of mind that I've strengthened the joint is worth something. Most folks actually like the look of the spline because it shows it's hand made.

The bigger the box, the more I'd lean toward using the splines.


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## Waldo88 (Nov 7, 2014)

For what its worth; I have a little walnut box with 1/4" sides that I made back in shop class more than 20 years ago, held together with nothing more than glued butt joints on the sides. As a 20-something I actually used to use it quite a bit and its been moved A LOT. Today its still as structurally sound as the day it was made.


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## shipwright (Sep 27, 2010)

A couple of folks have mentioned "modern" glues as if they believe that "old glues" were not as strong. Having used both I can tell you that about the only difference between "modern" glues and the hot hide glue that I use now is that I don't need clamps as often and my glue doesn't mess with my finish. Both are much stronger than most wood.

Sorry, just a bit of a sore spot.


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## RHutch (Jan 14, 2010)

I'm with you. Could easily hijack the thread with this one. 


> A couple of folks have mentioned "modern" glues as if they believe that "old glues" were not as strong. Having used both I can tell you that about the only difference between "modern" glues and the hot hide glue that I use now is that I don t need clamps as often and my glue doesn t mess with my finish. Both are much stronger than most wood.
> 
> Sorry, just a bit of a sore spot.
> 
> - shipwright


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## RHutch (Jan 14, 2010)

I've made some decorative boxes without taking the time to add the splines. I'm always wondering when they're going to let go. I'll never do it again.


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## Finn (May 26, 2010)

I have made well over a thousand small cedar boxes with mitered corners and no splines. In the 7 years I have been making them I have not had one come apart. I have also made larger cedar trunks and not used splines. I do install interior gussets in them though. I have made and sold about fifty of them. I once dropped one off of my bench onto a concrete floor and it hit on a corner with no damage. In my opinion splines in smaller boxes are decorative.


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## Dark_Lightning (Nov 20, 2009)

I have had small boxes break when I dropped them (a lot more than once) and have considered splines in the mitered corners. In retrospect, it may be that the joints were starved, as I only glue them up and haven't sized them first, even though I know better. As soon as I get my "honey-do" list and auto restoration objectives reduced, I'll be making some more boxes.


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## Pono (Mar 10, 2012)

Yes you have to have them a mitered end joint is the worst joint.The splines add strength and a decorative add on.I have made thousands of boxes close to 6k or more wholesale retail everything.All the samples i gave the customers commented on later that mine held up and not others you have to do it if you want it to last.









Easier to have your insides sanded and finished before glue up equal to what you do on outside helps it not warp


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