Pin Hinges
Updated 1/16/12
I spent a lot of time developing a way to let the lid swing down into the box, yet still maintaining a fairly tight reveal on all four sides
The difficulty is the lip itself. It doesnt allow the back of the lid to drop into the box, so thats where we need to cut it away a little deeper at the back. I call these pockets.
The other difficulty is in getting the hinge placement spot on or it wont open at all or not far enough to stay open.
Here is how its done:
Use the same pattern bit and bearing setup that you just finished using for the lip of the box. What we are going to do is crank the bearing up in several stages to cut deep pockets
just at the back for the lid to drop down into.
It will look like this.
The finished depth.
The finished width.
Set a fence 1 1/18'' to 1 3/4'' from the center of the bit.
You will need to experiment with this depending on your bit and bearing setup.
Pin Location:
As the lid drops into the box it scibes a larger arc than it would if we were using barrel hinges or butt hinges.
If we located the pins at the far back corner, then the lid would contact the back lip before it fully opened.
After much experimenting, I came up with a placement that allows the lid to swing down into the box and then lean back enough that it will stay open on its own. Also this location will position the pin in the center of the lid, after we grind away the top portion of the lid.
Remember we have a lid that is 3/4'' thick,and our recess is 1/2'' deep,which leaves 1/4'' of the lid standing out of the box.S o, if we shape the top of the lid down to the lip of the box we will end up with a lid that is only 1/2'' thick at its edges, which places the pin in the center of the edge.
Drill the hole the diameter of your brass pins. I use 1/8" brazing rod found at most hardware or welding supply stores.
Drill about 1 1/2" deep total. I am using a simple jig with steel bushings, one leg is for the left and the jig swings around to do the right. Tou can eyeball it with a hand drill or use a drill press.
If the pins are not in alignment the lid will swing up crookedly and bind up.
The lid will be off and on several times while you remove the wood on both the lid and box at the back. I use long roofing nails to act as temporary hinges, they are easier to get out. Polish them up so the slip in smoothly.
Before we can open the lid we need to pare away some wood on the top and bottom, at the very back edge.
Tip:
Wiggle the lid up and down when you have the pins in,even if its a little bit,remove the pins and look for rub marks where its tight and sand those away. Keep doing this.
Warning: I want to caution you about going too fast because it is very easy to remove too much wood at the back, leaving a thin line that will disappear if you grind into it. Final sanding will remove additional wood, aggravating the problem even more. If you arent sure how much wood you have left along the back edge, then just stay away from there when shaping.
This photo
shows a side view of the lid after beveling the top/back edge and bottom/back edge and corners. Final fine sanding will be done later.
Here you can see the line where we stopped the top bevel, and if you look to the far right, in the middle, you can see a flat spot about 1/4'' high.That is the only area that is still in contact with the back of the box. Carefully hand sand along this line until the lid opens without rubbing. Do this at a downward taper.
Keep in mind that your finish will add little material to each surface and you may get areas where it will rub.This is one of those things that depends on many factors including humidity. Just be sure it works pretty good for now and you can fine fit it later just before finishing.
And here we have a working lid.