21-09-2013, 07:23 PM
Over the years, I've made quite a few bits of simple test gear which ordinarily, in days gone by I'd have used plastic or aluminium 'project boxes' to house them. It dawned on me as a woodworker that I could make little comb-jointed boxes from scraps of oak, which would not only be money saving, but would also give a 'retro' appearance to my projects as so often, test gear, crystal sets and the like were housed in comb-jointed boxes. I keep my eyes open for scraps of oak flooring and such like in rubbish skips and from other sources, which I saw to the desired thickness on my band-saw, then sand on a belt sander.
You can of course buy jigs for making such joints, and dovetail joints, some of which are eye-wateringly expensive, and when a simple jig could be made at no costs from scraps of ply offcuts it made no sense anyway to buy something one can make. (In a similar vein, I can never quite grasp why woodturners by gouges and chisels with turned handles already on them when they can but unhandled chisels and gouges and make their own handles in minutes for next to nothing).
The following notes will make no sense at all unless read with reference to the pictures, but I hope they make sense with the pics!
The router jig consists of two main parts - a table on which to mount the router, with a guide slot to guide the other part - the 'sled' back and forth as slots are cut. I made the jig to cut 14/" slots to form comb joints, but the material can be thicker than 1/4" - up to say 1/2". On the front edge of the underside of the table is a 50mm square length of wood screwed to the table to enable it to be clamped in a woodworking vice when in use. The router is mounted beneath the table and router bit is set at the desired height plus 0.5mm clearance so that when the box has been assembled and glued up, the joints stand a little proud at the corners to allow them to be cleaned up on a belt sander.
The 'sled' has a guide piece that protrudes at the front which fits the guide slot so that the sled can move back and forth. A 1/4" 'peg' if fitted to the base of the sled over which the work-piece is slotted as each slot is cut. The work-piece is progressively moved along as each new slot is cut, to position the work-piece to cut the next slot. The work-piece is held firmly against the vertical front of the sled and the sled moved forward on the guide to cut each slot. The vertical front of the 'sled' has two panels with two slotted screw holes to allow for slight sideways adjustment as the slots and combs must be of exactly the same width or they'll be too tight or too loose. A test piece using scrap offcuts can be made first, to ensure that the combs fit together accurately.
When one work-piece has been cut, it's important for its mating piece to have the slots cut in the correct position so that the two pieces aren't offset. To achieve this, when the slots on the first piece have been cut, that pieces is reversed, placed against the 1/4" peg, and the mating piece butted up alongside it to cut the first slot in the second piece. I've attached a couple of pics of test pieces to show what the joints look like when assembled.
When the four sides have been glued up, I fit an oak ply base, and four fillets inside the box at each corner. I usually make front panels from scrap PCB material, which I spray white and add lettering made on a label printer as my CAD skills don't extend to making neat front panels.
Though I find it satisfying to make these little boxes, it's time-consuming so it makes no economic sense to make them as a 'going concern' for others - I get little enough hobby time as it is!
I hope that the above notes when read in conjunction with the pics, makes enough sense and provides enough information for anyone who might contemplate making such a jig, but if not I'll be happy to help further by PM.
You can of course buy jigs for making such joints, and dovetail joints, some of which are eye-wateringly expensive, and when a simple jig could be made at no costs from scraps of ply offcuts it made no sense anyway to buy something one can make. (In a similar vein, I can never quite grasp why woodturners by gouges and chisels with turned handles already on them when they can but unhandled chisels and gouges and make their own handles in minutes for next to nothing).
The following notes will make no sense at all unless read with reference to the pictures, but I hope they make sense with the pics!
The router jig consists of two main parts - a table on which to mount the router, with a guide slot to guide the other part - the 'sled' back and forth as slots are cut. I made the jig to cut 14/" slots to form comb joints, but the material can be thicker than 1/4" - up to say 1/2". On the front edge of the underside of the table is a 50mm square length of wood screwed to the table to enable it to be clamped in a woodworking vice when in use. The router is mounted beneath the table and router bit is set at the desired height plus 0.5mm clearance so that when the box has been assembled and glued up, the joints stand a little proud at the corners to allow them to be cleaned up on a belt sander.
The 'sled' has a guide piece that protrudes at the front which fits the guide slot so that the sled can move back and forth. A 1/4" 'peg' if fitted to the base of the sled over which the work-piece is slotted as each slot is cut. The work-piece is progressively moved along as each new slot is cut, to position the work-piece to cut the next slot. The work-piece is held firmly against the vertical front of the sled and the sled moved forward on the guide to cut each slot. The vertical front of the 'sled' has two panels with two slotted screw holes to allow for slight sideways adjustment as the slots and combs must be of exactly the same width or they'll be too tight or too loose. A test piece using scrap offcuts can be made first, to ensure that the combs fit together accurately.
When one work-piece has been cut, it's important for its mating piece to have the slots cut in the correct position so that the two pieces aren't offset. To achieve this, when the slots on the first piece have been cut, that pieces is reversed, placed against the 1/4" peg, and the mating piece butted up alongside it to cut the first slot in the second piece. I've attached a couple of pics of test pieces to show what the joints look like when assembled.
When the four sides have been glued up, I fit an oak ply base, and four fillets inside the box at each corner. I usually make front panels from scrap PCB material, which I spray white and add lettering made on a label printer as my CAD skills don't extend to making neat front panels.
Though I find it satisfying to make these little boxes, it's time-consuming so it makes no economic sense to make them as a 'going concern' for others - I get little enough hobby time as it is!
I hope that the above notes when read in conjunction with the pics, makes enough sense and provides enough information for anyone who might contemplate making such a jig, but if not I'll be happy to help further by PM.
Regards, David.
BVWS Member.
G-QRP Club Member 1339.
'I'm in my own little world, but I'm happy, and they know me here'
BVWS Member.
G-QRP Club Member 1339.
'I'm in my own little world, but I'm happy, and they know me here'
