Bird Mouth Joinery: A unique tool box 

Thanks for looking at the video, and glad you liked it! I have a list of future topics; let's see if my energy holds up. They are really fun to make!

+Old Man from Scene Twenty Four Thanks for your kind comment! Sorry I missed it earlier. It is strange that such a useful and venerable joint is so little recognized in recent times, despite the ready availability of easy-to-use router bits.

Thanks for your kind comments, ponkkaa! I think you'll have a lot of fun with your BMJ bits!

Kind words, much appreciated!

+Robert Ungar Comments much appreciated, Robert! Good luck with your BMJ projects. Questions? Contact me via my website!

Kind words indeed! Thanks!

tubbs094 Thank you!

Lou Adzima Thanks, Lou! Glad you liked it.

Thanks, Stefan!

Thank you very much! I'm glad you liked it.

Glad you enjoyed it. Many thanks!

Thanks Dublin47! I hope that your Irish Christmas was as fine as ours in San Diego!

Don Fillenworth Thanks, Don!

Thanks, Brent! Re thinner stock for the project, you're reading my mind. If I do this box again, I'll use 5/8" or possibly 1/2" stock. As is, it is rather heavy and probably unnecessarily so. I could have chosen less dense woods, too!

Thanks for the kind comments, Petrushka1611. I think that your idea of using fabricated panels as staves, instead solid wood, for a larger box is terrific! As long as the frames for the panels are strong enough overall, and have enough solid wood at the edges for the bird mouth joints, it should work just fine. And I don't see why there should be a stylistic clash at the corners; that would depend on how you design the panels. I can see both an inexpensive outer shell of veneered ply or something fancier like solid door panels built with thinner stock. I'd be delighted to hear how it turns out!

If I end up making something instead of just talking big, I'll definitely let you know. My wife decided to go with a plastic trunk, since it will be occasionally thrown in the back of a truck and knocked around, but I'm now thinking about making a hope chest for my niece.

+Jeff Pritchard Thanks for the kind words and insightful comments. I did think about wood expansion but in the end, because I wanted the box to be maximally strong, decided to risk it. The box is not all that wide and the woods in the bottom are relatively low in movement. Also, there is some compensating expansion of the box body from the cross grain corner pieces. And I have a habit of challenging the common wisdom where it doesn't seem to make sense. On a solid wood 36" wide tabletop, for example, I would definitely make allowances for wood movement. So far, and the box has been getting some serious use, it seems to be completely intact.

Thanks, Steve!

will you be doing any more projects?

Thanks for asking, Steve. Yes, I have a list of hope-to-do videos and am about 25% done with a new one. It details napkin holder construction, a topic that I mentioned briefly in my 8-side BMJ video.

great, will be watching for sure. Steve

I greatly appreciate your generous comments! Sorry about ignoring the handle shaping; it seemed like too much for a single video. It was done by approximate Forstner boring of the hand hole, bandsawing the outside curve, rounding off the hole and outside curve with a rasp, and a lot of sanding. Re using a dado stack for the joinery: why not? Typically, mast makers using BMJ use angle cuts with their table saw for the same purpose (two cuts are required.) For masts, stock thicker than 3/4" is often needed and the commercially available bird mouth router bits aren't big enough to handle it. Getting perfect joint angles with a table saw might take a lot of fussy adjustments, however.

David, thanks for the additional info much appreciated. I really liked the formula you added to the original info on these bits. Might want to add that as a link under your info about section.

Thanks for the nice comments! I appreciate your looking at it. Re the glued-in panels; I was wondering if someone would call me on it. My intent was to rigidify the box, as it will be hauled around and no doubt get banged up with rough handling. As I see it, the width of the panel is borderline for requiring allowance for movement, so I took the chance. Time will tell; I'll fess up if I start to get popped joints. There is one other violation of construction conventional wisdom that may catch up with me!

Hi Tim! Glad you enjoyed the video. No tray inside but it would be easy to make one as a drop-in. It could be built essentially the same way as the lid, but slightly smaller so that it would slip inside the box. I am using the box for hauling tools around but it doesn't get a lot of action; so far not much gouging or scratching, etc.

David - Thanks for your comments! Glad you liked the video. You are not the first to notice some of my glue-up practices. In this case I may be near the size limit for getting away with neglecting wood expansion. I decided to do it because I wanted maximum strength in the box; I expect it to get banged around quite a bit. I'll fess up if I have joint separation in the future. I'm also at risk with the cross-grain corner glue joints. I've been making smaller containers using this construction methods for years without problems.

I was thinking the exact same thing. On the top I see the need for strength (after all thats where the handle is) but I have some reservations about the bottom half, with the crossgrain corners and the fully glued bottom. I would guess the type of finish, or lack thereof, may be the determining factor of how much expansion and contracting will affect it.

Gracias, gra643!

Thanks, Joe! I don't see why it couldn't be beveled as you suggest, with the benefit of a better seal. I've thought about putting interlocking lips on the top and bottom to ensure a rigid alignment and tight seal, but never tried it. Any thoughts on how to go about it?

Thanks for the comment and question. It is an entirely valid concern and quite a few other woodworkers have asked about my use of cross-grain glue joints. Unequal wood expansion between the two parts of the joint is the concern here, and must be taken into account for larger projects such as cabinets or tables. As the size of a glue joint decreases, however, joint stress also decreases. This tool box is the largest piece where I have used cross-grain glue joints and, more than two years after assembly, with frequent handling, there is no sign of joint separation. On smaller, earlier pieces cross-grain joints are still good after at least 8 years. So far, I have never seen a failure. I use these joints because, combined with bird mouth joinery, they offer easy access to a wide range of decorative and design options.

It's a valid point. After some thinking I've figured that longer sides are fixed to a bottom frame, and that they constrain angle pieces mechanically. Even minimal adhesion should keep the joint strong.

Hi James. Thanks for your comment! I was waiting for someone to question me on my cross-grain glue joints! I have been doing this for several years on somewhat smaller boxes, and have had no problems so far. This toolbox is the biggest example that I've tried it on, and it may be pushing the limits; if I have trouble in the future I'll comment on it. Three months of substantially varying temperature and humidity here since it was assembled haven't caused problems (yet!) Re reinforcing bird mouth joints, I hadn't given it much thought until now. My first thought is that it's ordinarily not necessary. If special circumstances require it, splines might work, wouldn't be difficult, and could add a nice decorative touch. It's possible that some type of biscuit or floating tenon could be inserted, but the fabrication set-up might be complicated. I'd be interested in any thoughts that you have on the subject. Do you have a specific application in mind?

davidhenry32 Thanks Dave. I have made some desks in the past, all with traditional joinery; mortise and tenon, dovetailed drawers, etc., but in the past few years I have only been doing small projects, like jewelry boxes and bandsaw boxes. (A big factor is the cost of good wood.) I found your video on bird mouth joints to be very interesting. I'm sure I had seen the joint before in one of my woodworking books, but never thought of using it, mainly because I always make four-sided boxes. Now that you have demonstrated it though, I will probably give it a try. I don't think I will buy the router bit though. I think for me it would be better to use a dado stack on my table saw. I think it would work just fine. In my mind I envision making a sled sloping at 22-1/2* rather than tilting the dado. I would have to do some experiments though to test out the idea. About reinforcing the joints - I was mostly just thinking out loud, wondering if you had ever needed to do so. I guess on your vases with vertical grain joints any reinforcement would be superfluous, but I can see on horizontal grain joints the possible need for a spline of some sort. Thanks for making the video. It was very instructive, and enlightening.

James Carr James - thanks for the useful and informative reply! I really like your dado stack idea; it has the potential to overcome one of the significant limitations of the commercially available router bits. They are good only for stock thickness up to about 3/4". If you try it, I would very much like to hear how it turns out. I've never seen the idea suggested before.

+gary24752 Hi Gary! Thanks for checking out my video. The 8-side bird mouth router bit used for the project was purchased from Lee Valley, but similar bits are available from several sources, e.g. search Amazon for bird mouth router bits.

Hi Bill! I'm a long way from an expert on glue but I would be careful about using wood glues on stained or otherwise finished wood. The chemistry of wood glues is aimed at sticking to raw wood fibers and any prior finishing raises questions in my mind. I'm sure that in some cases, with some stains and some glues, the glue bond would be OK but I wouldn't risk it if you are counting on a full strength bond. If sanding off the stain is not possible, I suggest trying epoxy glue; that seems to bond to almost anything. Good luck!

Hi Charlie! It's great to get a message from Ireland! The Whiteside 3508 bit appears to be exactly the same as the 8-side bit from Lee Valley that I use in my videos; I just checked it out. The bit height settings should be similar; for 3/4" stock, 3/16". For 1/2" stock, 1/8". The generalization for the 8-side bit is to set the bit height at one fourth the thickness of the stock, then do tests and make any small adjustments as necessary. Good luck!

The problem was almost certainly taking a cut that was too big. For 3/4" stock I always take at least two passes to reach the final depth of cut. The 6- and 8-side bits take a pretty big bite. The kind of wood also makes a big difference. A few preliminary experiments, as you point out, are a good idea.

Thanks, Julien! Glad you like them!

Russ Veinot Hi Russ Thanks for your comment! You're not the first to question me on my cross-grain glue joints and I realize that this contradicts a common wisdom of the woodworking world. However, I have been doing this for several years on somewhat smaller boxes (check my website), and have had no problems so far. This toolbox is the largest example that I've tried it on, and I'm sure there is an upper limit, depending on the species of wood and range of humidity changes the box will experience. Almost a year of substantially varying temperature and humidity here (San Diego area) haven't yet caused problems. I kind of enjoy challenging the common wisdom and, in this case, feel that employing crossgrain joints in a thoughtful way substantially increases my range of design opportunities.

Thanks for your very kind words, mcneile3! A great Christmas present!.

Hi, Carlos! Thanks for your kind words. Hopefully, more videos are coming.

Thanks, Pete!

+David Handley Thanks for your interesting insights! I agree that there is a similarity to locking miter joints. Both joints hold the work pieces tightly where you want them, very useful for assembly. Using bird mouth joints requires more parts and therefore a bit more (but easy!) work, but has the advantage of allowing multiple sides in a box and more decorative potential.

+Atif Hasan Hi Atif! Thanks for the kind words and for looking at my video. I've been using the toolbox for over a year now and it does have a scratch or two. The polyurethane finish seems to help minimize the biffs and scrapes. I've since built one out of 1/2" plywood (with a simpler handle) that is just as strong and significantly lighter in weight.

Very glad you like them! And let me know how the work with the 8-side bit goes. I consider that bit the most versatile of all of them.

davidhenry32 I'm going to make some bowls, and some flower pots, and some boxes. Just bought a bunch of wood. If all goes well, I'll take some pictures. I'm glad to hear that you think the 8 sided bit is the most versatile. It was the first one I bought, and I was hoping I hadn't chosen badly. :-)

Hi Nick! I'm sure that 1/2" baltic birch would work. I used it for a similar but smaller box without problems. Thanks for your interest!

davidhenry32 thanks for the reply. You earned a subscriber because your toolbox video went so far in effort to avoid showing standard work while still displaying it clearly and focusing on the subject at hand: joinery with birds mouth bits. Thanks for your work.

Many thanks for the comment and question, James! Re cutting apart a single assembly: good eye! This is a very practical idea and I use it often for smaller boxes. In this case my canary stock was not quite wide enough to get the box height where I wanted it. I have a video on building napkin holders coming soon (hah!) that relies on this idea.

That makes sense. After I commented I think I noticed you used that technique on another box. I only asked because I thought there might have been a reason other than stock width. I'm definitely looking forward to trying this AND to seeing your next video.

+Jack Derouen Thanks, Jack!

Thanks for the kind words, Juan! Sorry about omitting any details on making the handle; I was worried about the length of the video and was trying to emphasize the bird mouth joinery aspect of the box construction. The handle started with a 1x3x20" piece of lytchee. After laying out the desired shape, the hand hole was roughly bored out with multiple passes with two sizes of Forstner bit, and the outside curve cut by band saw. The final handle shape was completed by use of a rasp, and a lot of sanding. The handle piece was then glued between the two pieces of canary wood that form the other parts of the lid.

davidhenry32 Thank you very much for the description of how you made the handle, your work it is certainly first class, I enjoyed you video a great deal and I am looking forward for the next one. good work.

Glad you enjoyed it!

+lewis irvine Thanks, Lewis!

Thank you for your generous comments, Malcolm! I have a RU-vid channel (davidhenry32) where all 10 of my videos can be found.

Thanks, Terje! If you buy those bits, I think you will have a lot of fun exploring with them.

Thanks, Erik! I hope that you give bird mouth joinery a try!

Thanks, MRrwmac! It was fun to do.

Hi Raymond! Glad you enjoyed the video! I mostly use bits from Lee Valley where they are called bird's-mouth joinery bits in the online catalog. For a variety of other suppliers, search Amazon for birds mouth router bits. Good luck with the bits; I'm sure that you will have a lot of fun with them!

Thanks, Yonatan!

bert kraan Thanks, Bert! As I have explored bird mouth joinery over the past several years, It has been amazing to discover how versatile it is.

Hi Jamie - Comments like yours make it all worthwhile!

How kind of you! Thanks, Leopoldo!

Thanks, Simon!