|September 30. 2006|
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Dovetail machine 101 & 102
Porter-Cable Dovetail Machine
How do I use my new 12" dovetail jig I got from: Porter-cable, Sears, Harbor Frieght...etc. Answer:
With lots of patience!
HAHAHAHA I own the Porter-Cable one, but I'm almost certian that all of these half-blind dovetail jigs are about the same, just made with different materials. For example my P-C uses hardened aluminum for the template and others are made of plastic; mine cost's more but will it make better joints Most likely not, but it may last longer. The way they are used is all about the same. This article deals with 1/2" dovetails only, other sizes will require a different template and different directions/ demisions. Now for the Directions Assemble the jig as shown in the directions or so it matches a good picture. Install either a 14deg 1/2" dovetail bit with a 'top' mounted 5/8" bearing or a 14deg 1/2" dovetail bit and a 5/8" Guide bushing in your router. Turn your router upside down, set template on top of router and adjust depth until you have 9/32" of bit projecting beyond the template. Remove the template, measure the bit height above your router's base plate and write this distance down. You may need this setting later, you'll find out in step four. See picture to the right::
Take your drawer front and place it inside up on the top of your jig. Place the template over this so that there is slight friction betwee the two but do not let the drawer front hang over the front edge of the jig. Slide the drawer side up, inside facing out until it touches the fingers on the template and secure. Make sure that the edge lines up with the center of a gullet in the template. Your jig should have came with an 'L' bracket that sets this offset between the front and side. Slide the D. front so that it contacts the side, as in picture. Tighten all the clamps and check the listed demsions. The critical demensions are shown on the pic. 3/16" from edge of gullet or finger to edge of front. Bottom dead center of gullet should be 19/32" from end of front. See pic to the left::
After double and triple checking your set up place router on top of template and climb cut slightly, move router right to left to score drawer side, then final cut left to right. You may not have to score the side if you are using solid wood but scoring will lessen chip-out. Now for the Test Dry fit the pieces together. Take the top out of the jig, then remove the side and assemble. Your fit should be a snug, not tight fit. If the fit of the joint is too loose increase slightly the depth of cut, that is to say set bit projection to 19/64". If the joint is too tight, which in my case is more likely, decrease depth of cut. Once you are happy about the fit of the joint re-measure the bit projection and write it down, you will need this next time. If you change to a different bit, same size, type, but different copy, re-test for fit, which you should do on each project anyway. If you measured carefully then most likely your test cuts will be fine. How does the edge of the drawer side line up with the edge of the front? The pins (front) should be dead even with the side of the drawer or slightly proud. If proud sand to finish. If way proud decrease 19/32" demension, edge of front to bottom dead center of gullet. If your drawer side will not seat flush or slightly below flush increase gullet depth The picture above shows the left side and left front mounted in the jig. If your drawer top and side don't meet correctly, increase or decrease 3/16" demension. When you are done you should have a half of a pin on the top of your drawer front. Finally make sure you have written all of the demsions that have worked for you. You might want them in the future. If you really want a half pin at both the top and bottom of your drawers cut your sides and fronts wider (deeper) than you think final size will be and once the tails and pins are cut to satisfaction trim to width (depth).
Dado for your bottoms as a final milling step so that you make sure that the dado lines up with a tail, otherwise it will show on the side. Lightly label all drawer parts with pencil so that you don't get rights and lefts confused. Hopefully if you did everything right it will look even better than this.
The drawer sides will have to routed seperatly. To route the tail board or drawer sides you will have to install a piece of scrap as a backer board in the top of your machine and the drawer sides just like for regular drawers.Picture of set up with backer board installed.
Install your front, inside up in your machine noteing the offset demension in the picture. You may have to remove the nylon spacers from under the front clamp knobs. They are shown in this picture off to the right.
After you have routed all the pins finish the fronts by ripping to width and rabbeting the top and bottom. Mark a line centered on top of a pin, measure over towards the board's edge the distance of your rabbet's width, mark another line to rip off. as in picture.
Cutting rabbet. Drawer front ready for next step: dadoing for bottom.Make sure you cut the dado for the drawer bottom between pins as shown or it will show from the side.