While the rest of the world is going forward I seem to be going in the other direction, ie; wooden hinges. I bought a book from FWW back in 1998 showing router projects and techniques culled from past magazine articles. There was an article there by Rob Cosman.which included a method of making wooden hinges. This is the type of hinge in question shown on my box below.
Main Problems producing a hinge using Rob Cosman’s method
In Cosman’s article, after making the hinge dowell the right diameter and length and cutting the individual segments, the next job was to drill short holes into the ends of each segment. As you most of you know, it is a daunting task to get these holes centered. Cosman had a special jig machined for him especially for this job. He then cut the welding rod hinge pin into short pieces to be inserted in the end holes between the segments. This works very well if you have that special jig. I tried it without and got a result that was so so, but I wasn’t satisfied with it. After a sojourn of a few years the little gray cells started working and I came up with a method that would work well without the jig. I am very grateful to Rob Cosman for his great article and introducing me to this type of hinge. They work very well, are more than strong enough and are, I think, pleasing to the eye. I have since learned that tea boxes in Scotland were made with this type of hinge during the 19th century and perhaps earlier. Here is a couple of links to some of them in case you are interested. The first one has the hinge in question. http://www.hygra.com/uk/tc/tc106/ and http://www.hygra.com/visualtea.html
Summary of work
The hinge starts out as a square stick which is composed of two halves. A small “v” groove is routed along the inside middle of each half to accept the one piece long hinge pin which is a welding rod. After routing the hinge halves are glued up and clamped. The next step is to create a round dowel of the glued piece to final dimension and then measure the length needed against the box it’s going on. This length should be divided into equal lengths preferably using an odd number of segments. The hinge pictured on the box above has 7 segments, but this hinge will only have 5. The segments are numbered with arrows indicating grain direction to keep them in the original order and then they are cut. The segments are then threaded onto the hinge pin and they are ready for gluing onto the box. The next and final blog on this will cover routing a mortise into the box and gluing the hinge into it.
Blog addendum added 27/01/2010
Antonio (Antmjr) has already come up with a new and better method to construct the hinge. If you use his method shown in in 3 photos below in the comments area, you will be able to skip the two piece routing, A glue-up is still required, but as you will see, much simpler and a lot quicker. You will have to use hinge pin that is of a diameter as the width of your saw kerf to keep the hinge stabil.
Many of you more experienced and knowledgeable woodworkers will have better ways to carry out the work described here, but I have tried to include as many as possible regardless of skill level, and to describe and show the work in great detail for that reason.
1. Router (best with a small or large table attached and a fence, but doable without)
2. Small hand plane or a machine planer
3. Any kind of saw that you can saw a reasonably straight line with.
4. A variable speed hand drill with an “on” lock
5 A sanding disk (optional)
6. A miter saw (optional)
7. Wood lathe (optional)
1. Steel Welding Rod 2mm or 1/16” diam. (hinge pin)
2. Sandpaper in following grits: 60, 100, and 180 or whatever you want to use.
3. Two small pieces of wood joined in an “L” shape so that it can be clamped to a bench. (Not needed for lathe owners)
As you can see I have tried to tailor this tutorial to someone with a limited tool kit, but if you have more, then of course it will save you some time and effort.
Step 1: Preparing stock
We need some wood. I’m using Birch here as the hinge will be used on my grandson’s birch plywood box.
The final diameter of the hinge will be 13mm or 1/2”, but I have cut the piece at 15mm thickness which is about 1/16” over the final dimension of 13mm or 1/2” thickness to allow for further cutting. This piece should be jointed and planed so that it is flat on both sides and of an even thickness. If you can’t plane it then you will have to figure this out yourself. The hinge diameter is determined by the size of your router cove bit.
Step 2: Cutting the hinge parts
I first ripped off a stick like on the thicker piece furthest right at a width of 18mm or close to 3/4”. This excess width will be reduced to 15mm when it is ripped in two pieces as shown to the left in the photo. That will result in 15mm square when the two pieces are rejoined which is a little over the final dimension. Be sure to rip the the wider side of the stick to end up with the correct width on all four sides. This all assumes you are cutting with a 1/8” blade.
Step 3: Preparing for gluing the two halves of the hinge together
You will be gluing the outsides of the two matching pieces together eventually, so here is where the prior jointing and planing will be appreciated. I still sanded mine on a sanding board in order to get an almost totally invisible glue line as shown below. So after this little job the mating pieces are very flat and when put together will form a square stick.
Step 4: Getting the hinge pin ready and setting up for routing
Next I prepare my hinge pin. I can’t buy welding rod without flux on it, so I have to hammer it off. This takes 30 seconds, then I go over it with sandpaper for another 15 seconds and It’s done. Now the rod can be used to set the height of my rounter bit which is an arrowhead bit or whatever you call it there. I set the bit height to 1/2 the diameter of the rod. It portrudes just a tiny bit above the table by 1mm or slightly more that 1/32”. Be aware that if you are using wood with a high tannin content such as Oak for example, it will react with the steel hinge pin. To counteract this reaction you need to either seal the groove the pin sits in or the pin itself. I haven’t done this myself, but I think the groove could be sealed with polyurethane and probably the same for the pin. However, you might want to check this out from a better source to be sure.
Step 5: Routing
A little “V” groove will be routed exactly in the middle of the inside of each hinge piece to house the hinge pin. The pin will remain in one piece unlike Rob Cosman’s version. This means that you will be able to remove the top of the box at any time after final installation by simply using a small punch to tap out the pin enough so it protrudes a little on the other end and then pulling it out the rest of the way with a pliers. Please note that I’m using the simple little router table that I showed how to build in a recent blog.
Ok we are almost ready for glue-up, but first we have to check the fit of the hinge pin. Oh oh, a little loose! No problem, we just do a little planing or sanding if you prefer. Now you know one of the reasons for being a little over-dimensioned.
Ok, now were good for go. The hinge pin should be a tight fit! We are ready for glue-up. I glued up without the hinge pin inserted. If you are putting the hinge on a lathe for rounding then I would suggest you insert the hinge pin while the glue is still moist and then pull it out again and wipe off any glue on it. This is just to clean out the hole. If you will be planing and sanding the hinge round as shown below then I suggest letting the glue dry before inserting the hinge pin. I may take a little force to get it through, but you will have a very tight fit that helps with the with the rounding. I ground a little edge on the end of the hinge pin to help cut it’s way through. Don’t use too much glue or you will never get the hinge pin through!
You can laugh at all these clamps (I did), but the glue-line came out great. Watch out for slippage under clamping.
Now to find a washer that is the final hinge diameter. Found it! Next step to center it on both ends of the hinge piece and put pencil lines around it. This will be your guide to plane, sand or whatever to knock off the corner edges. I used a block plane for this.
Step 6: Making a sanding jig for rounding
The planing is done, so now I am making a little sanding jig that runs off my hand drill. As you can see it’s pretty simple. I have inserted the hinge pin and it’s tight enough to drive the hinge around at a moderate fast speed. Note that the other end of the hinge pin revolves in that little hole being shown. The hole should be just a hair larger than the hinge pin so it will run smooth. Both ends of the jig are clamped securely down. It’s important that the hinge be properly aligned between the two ends and that the hinge is level. If you hinge pin is too loose to drive the hinge then I would suggest you epoxy glue the both ends temporarily, melt glue might work too. The advantage of using the hinge pin to drive the hinge is that the hinge pin will remain centered. This is a sanding jig and should not under any circumstances be used as a lathe.
The hinge will be rounded using 60 grit sandpaper. The sandpaper is best folded into a square and it should be held onto the bottom of the hinge while it revolves driven by the drill. Be patient and don’t apply a lot of force or you will bend the relatively weak weld rod drive shaft. It took me about an 1/2 hour to get it round. I could have done it on my lathe in a couple of minutes. I used a caliper set to 13mm or 1/2” to check my progress and when I was near finished I used the finer grits of sandpaper to get a nice surface.
Step 7: Cutting the hinge segments
First remove the hinge pin (photo1), then measure the width of your box (side to side) and then divide that measurement by the number of hinge segments , in this case 5 (photo2). Now set up your cut with a stop block on your saw. Cut each segment about 2mm or 1/32” long (photo3). This will allow you sand the ends a little flatter on a sanding disk or whatever. Make sure the ends of the segments are 90 degrees to the sides. Be careful not to sand off too much*
Now the hinge segments put back on the hinge pin in numbered order and with the arrows all pointing in the same direction. The hinge as shown below is now ready to be glue into the box.
The next installment will probably be next Monday or Tuesday If my grandson can come over to finish the box on the weekend.
I’m sorry this blog is so long winded. The Rob Cosman article had about 3 pictures and a short paragraph or two to explain his method, but I’m not very good at this so quantity outweighs quality for me. Thanks a lot for reading, and I hope you found it interesting and/or rewarding.
-- Mike, American in Norway The four steps towards competency: 1. unconscious incompetence, 2. conscious incompetence, 3. conscious competence, 4. unconscious competence