03-01-2017, 11:25 PM
I'm working on a project and wanted a somewhat infinitely adjustable doweling jig that would allow me to work quickly and accurately.
What I came up with is a drilling jig made with two bushings (one for 1/4" dowels, one for 3/8"). The jig is used with a template that is purpose made for the project at hand.
The dowel jig allows me to lay-out a template specific to the dimensions of the piece I'm building. The jig employs 1/4" and 3/8" (ID) steel spacers as drill bushings driven into a small block of plywood and extending about 1/4" beyond the face. They're arranged in such a way that the jig can be flipped, depending on the size of the dowel holes I'm wanting to use.
The part of the bushing that extends beyond the face fits into holes I'll drill in the template. That is essentially the jig, crazy simple, eh?
The only problem is that the spacers/bushings are slightly (a few thousandths) oversized (OD) as they come from my local Ace hardware. So I chucked them in the drill press (I don't have a lathe) and used a file to reduce the OD for the last 1/4" or so. I employed a small block of wood with 3/8" and 1/2" test holes so I could sneak-up on the perfect OD.
Once I had the bushings filed, I made a small block of 3/4" Baltic plywood to hold them. The size really isn't that important but I'd suggest keeping the width a hair under 3/4" to make the jig it a little more flexible on narrow stock. I drilled the holes in the plywood block 1/64" undersized, and used my vise to push-fit them into the block of wood. They're snug in there, they aren't coming out. In fact, if you want to get them out, you will need to destroy the block. Don't ask me how I know.
FWIW, plywood works better for the block (vs. solid wood). My first solid wood block works fine, a subsequent attempt split the wood. The plywood won't split.
Next up was a template so I could test my concept on some test pieces (some scrap). I simply picked where I'd like a (1/4") dowel and drilled a corresponding hole (3/8") in the template. I added a final 3/8" hole that I could slip a dowel into and use it for an edge reference, to help keep the dowel holes aligned between the pieces.
The template is just 3/8" plywood (more Baltic). It could be hardboard, too, I suppose.
Now, this aspect will be more difficult to describe than to actually do, but that 3/8" dowel provides an edge reference that stays the same between all the pieces I'm drilling holes into. It is always pulled tight to the front edge or rear edge of each workpiece. Pick the front or the rear and mark the same edge on all your workpieces before you begin drilling holes.
One edge of the long dimension is a 2nd reference and I mark it on both the top and bottom of the template, this edge is ALWAYS OUT. You could just as easily call it ALWAYS IN or ALWAYS UP or ALWAYS DOWN, but you have to be consistent, no matter what you pick. Once you pick your 2nd reference, mark all your workpieces before you start drilling.
Whether I'm drilling the ends of the sides of the box, or the faces of the top/bottom, that ALWAYS OUT side of the template is facing what will be the outside of the box, and the dowel is pulled snug to the back of the workpiece.
When changing from drilling the sides of the cabinet, to the faces of the top/bottom, I have to flip the template but the ALWAYS OUT edge of the template has to remain to the outside of the piece I'm drilling, and that dowel always has to be pull snug against whatever I picked as my first reference (front or back).
But basically, by flipping the template, I'm guaranteed any error in the hole alignment symmetry on the template is reversed, so the holes in the two workpieces are aligned PERFECTLY.
So many poorly chosen words for something that is actually quite easy.
Anyway, the template doweling jig worked great and is very flexible and cost only a couple of bucks and 25-minutes to make, figured I'd share it here.
The project I'm currently working on is an old-school plywood sub box so I can relive my youth a little. Using this jig I was able to very quickly drill all the necessary holes and the alignment was truly perfect.
FWIW, I could have used one of my other dowel jigs (I have a dowel jig museum in my shop if anyone would like to visit) but when working with joints 18" wide, I'd have to shift even my longest jig once, and I didn't want to have to keep track of which holes and drill and which to skip. And I just wanted to try an idea that was banging around upstairs for a while.
Anyway, I've provided some pics, maybe it will give others ideas to try.
What I came up with is a drilling jig made with two bushings (one for 1/4" dowels, one for 3/8"). The jig is used with a template that is purpose made for the project at hand.
The dowel jig allows me to lay-out a template specific to the dimensions of the piece I'm building. The jig employs 1/4" and 3/8" (ID) steel spacers as drill bushings driven into a small block of plywood and extending about 1/4" beyond the face. They're arranged in such a way that the jig can be flipped, depending on the size of the dowel holes I'm wanting to use.
The part of the bushing that extends beyond the face fits into holes I'll drill in the template. That is essentially the jig, crazy simple, eh?
The only problem is that the spacers/bushings are slightly (a few thousandths) oversized (OD) as they come from my local Ace hardware. So I chucked them in the drill press (I don't have a lathe) and used a file to reduce the OD for the last 1/4" or so. I employed a small block of wood with 3/8" and 1/2" test holes so I could sneak-up on the perfect OD.
Once I had the bushings filed, I made a small block of 3/4" Baltic plywood to hold them. The size really isn't that important but I'd suggest keeping the width a hair under 3/4" to make the jig it a little more flexible on narrow stock. I drilled the holes in the plywood block 1/64" undersized, and used my vise to push-fit them into the block of wood. They're snug in there, they aren't coming out. In fact, if you want to get them out, you will need to destroy the block. Don't ask me how I know.
FWIW, plywood works better for the block (vs. solid wood). My first solid wood block works fine, a subsequent attempt split the wood. The plywood won't split.
Next up was a template so I could test my concept on some test pieces (some scrap). I simply picked where I'd like a (1/4") dowel and drilled a corresponding hole (3/8") in the template. I added a final 3/8" hole that I could slip a dowel into and use it for an edge reference, to help keep the dowel holes aligned between the pieces.
The template is just 3/8" plywood (more Baltic). It could be hardboard, too, I suppose.
Now, this aspect will be more difficult to describe than to actually do, but that 3/8" dowel provides an edge reference that stays the same between all the pieces I'm drilling holes into. It is always pulled tight to the front edge or rear edge of each workpiece. Pick the front or the rear and mark the same edge on all your workpieces before you begin drilling holes.
One edge of the long dimension is a 2nd reference and I mark it on both the top and bottom of the template, this edge is ALWAYS OUT. You could just as easily call it ALWAYS IN or ALWAYS UP or ALWAYS DOWN, but you have to be consistent, no matter what you pick. Once you pick your 2nd reference, mark all your workpieces before you start drilling.
Whether I'm drilling the ends of the sides of the box, or the faces of the top/bottom, that ALWAYS OUT side of the template is facing what will be the outside of the box, and the dowel is pulled snug to the back of the workpiece.
When changing from drilling the sides of the cabinet, to the faces of the top/bottom, I have to flip the template but the ALWAYS OUT edge of the template has to remain to the outside of the piece I'm drilling, and that dowel always has to be pull snug against whatever I picked as my first reference (front or back).
But basically, by flipping the template, I'm guaranteed any error in the hole alignment symmetry on the template is reversed, so the holes in the two workpieces are aligned PERFECTLY.
So many poorly chosen words for something that is actually quite easy.
Anyway, the template doweling jig worked great and is very flexible and cost only a couple of bucks and 25-minutes to make, figured I'd share it here.
The project I'm currently working on is an old-school plywood sub box so I can relive my youth a little. Using this jig I was able to very quickly drill all the necessary holes and the alignment was truly perfect.
FWIW, I could have used one of my other dowel jigs (I have a dowel jig museum in my shop if anyone would like to visit) but when working with joints 18" wide, I'd have to shift even my longest jig once, and I didn't want to have to keep track of which holes and drill and which to skip. And I just wanted to try an idea that was banging around upstairs for a while.
Anyway, I've provided some pics, maybe it will give others ideas to try.