Joinery | Syzygy Woodworks

September 29, 2010

Lock-Rabbet Drawer Joint

A lock-rabbet joint, while not as strong as a dovetail joint, is still a strong, attractive and relatively easy joint to make. It is ideally suited for drawers. It can be made on either a table saw or router table.

As with much power tool woodworking, the time is in the set up. Once the set up is done, repeating the cut for any number of drawers is a quick process.

The first step is to mill your lumber. The picture below shows the pieces for one drawer box. The sides are 1/2″ thick maple, the front and back are 3/4″ maple. The length of the drawer front and back pieces is the same as the finished dimension of the drawer. The lengths of the drawer side pieces is half an inch less than the finished dimension of the drawer. As always, I have also prepared a couple of 1/2″ and 3/4″ scrap pieces to use for test cuts during the set up. It’s also a good idea to mark the outside face of each piece with chalk to avoid confusion.

With a 1/4″ dado blade in the table saw, cut a 1/4″ x 1/4″ groove down the side of each piece 1/4″ from the edge of the piece. This is the groove that will accept the drawer bottom, which is 1/4″ thick sheet material. Cutting the groove now gives you another visual aid as to which side is the inside of the drawer as well as which edge is the top and bottom.

Using one of the drawer sides as a gauge block, raise the 1/4″ dado blade to 1/2″ high. This is a rough adjustment and the blade height will be fine tuned in the next step.

The next step can be made by using a tall auxiliary table saw fence or with a tenoning jig as shown in the picture below. Using a scrap piece of wood and the blade at 1/2″ height, make a cut.

To confirm the blade is at the correct height, butt one of the drawer sides into the groove just cut. The drawer side should fit flush with the edge of the scrap piece, as in the picture below. If the drawer side is proud of the edge of the scrap piece, then the cut needs to be deeper and the blade should be raised. If the edge of the scrap piece is proud of the drawer side, then the cut is to deep and the blade should be lowered.

Now that the height of the blade is set, the distance from the tenoning jig to the blade needs to be set to 1/4″. I like to use a brass set up gauge for this.

With the outside face towards the tenoning jig, cut a 1/2″ x 1/4″ groove in the end of each side of the front and back pieces of the drawer.

Using either an auxillary fence on the table saw, or a piece of wood held with a fence clamp as shown, slide the table saw fence so that the piece of wood just touches the blade.

Lower the blade to 3/8″ of an inch.

With the outside face of the piece up, crosscut each end of the front and back pieces of the drawer.

The front and back pieces of the drawer are now complete.

Still using either a scrap piece of wood held by a fence clamp, set the height of the blade to 1/4″ and the distance of the blade from the scrap piece of wood to 1/4″. Then make a crosscut in one of the 1/2″ thick pieces of wood you prepared.

The astute among you will notice that I made a large block of wood to use as my “mini auxillary fence”. The one in the previous image did not reach all the way down to the table saw bed and made some set ups difficult.

The really astute among you will also notice that the position of the “mini auxiliary fence” in the shot below is far from ideal. Somewhere in the midst of making the new auxiliary fence, performing the cross-cut and then staging everything for the photo I had the auxiliary fence in the wrong position. My bad. Once the distance between the fence and the blade is established, the auxiliary fence should be moved back behind the blade, where it can perform it’s function as a stop block but not run the risk of binding the piece as you perform the cross cut.

This image shows the correct position of the auxiliary fence/stop block relative to the blade while performing a cross cut.

Proceeding on, the image below shows the results of the test cut. The piece is sitting proud of the edge of the drawer front by a smidgen. To correct this the blade needs to be raised by a corresponding smidgen.

The correct fit after raising the blade is shown below.

Once the correct fit is established, the cross cut is made on each end of both drawer sides with the outside of each drawer side facing up.

All that needs to be done is to perform a dry assembly of the drawer, establish the size of the drawer bottom, cut it and then a dry assembly of the drawer with the bottom in place.

When gluing the drawer together, checking the diagonals match is an easy way to ensure that the box is square. I find the square check for tape measures really convenient for this.

August 16, 2010

Building a Flat Panel Door

A flat panel door can be defined as a door in which the panel has no bevel or hip raise. It can still be considered a five piece door, as it consists of two stiles, two frames and a panel. The stiles are the vertical members of the frame, while the rails are the horizontal members.

The first step is to mill the wood for the stiles and rails of the doors. I am building three doors for some base cabinets. All three doors are the same size and the cabinets will be painted white. I am using poplar for the frame of the door and 1/4″ plywood for the flat panel. The stiles and rails are 2 1/2″ wide, 3/4″ thick and I cut them an inch or so longer than what I needed. While I was preparing the wood I also took the time to make some scrap pieces the same width and thickness to be used for test cuts. You can also see my set up block in the picture. You can also see my raised panel router bit set. For this project I will only be using the two bits on the left, the monster raised panel bit will stay in the box.

Mount the bit for cutting the profile on one edge of the stile and rails. I use my set up block to adjust the height of the router bit, although I still plan on making some test cuts in scrap wood. The profile in both the stiles and rails will be cut with the face side (the outside of the door) down.

A close up shot of my set up block. I keep this in a drawer right next to my raised panel router bit set.

The fence is then moved so that it is flush with the bearing of the bit.

After routing a profile in a scrap piece of wood, I use the rail section of my set up block to see if the two surfaces meet flush on the top surface. I got lucky this time and the fit was perfect 🙂

I then routed the profile on one edge of all the stiles and rails. Remember the cuts are made with the show side down. For this project it was not that important as the doors will be painted, but if you are not painting the doors you will want to take care to chose the best side of each stile and rail and then to route it with that side down.

I then took the stiles to the table saw and used a cross cut sled cut them to length. To calculate this length I measure the height of the door opening and added 1 /4″. My crosscut sled was not quite wide enough to enable me to use its stop block, so I used a fence clamp and a block of wood as a stop block.

The next step was to calculate the length of the rails. I wanted the door to overlap the door opening by 5/8″ all round. The depth of the groove in the stiles was 3/8″. The width of the stiles was 2 1/2″. So the length of the stiles needed to be:

(Door opening width) + (2 times 5/8″) – (2 times 2 1/2″) + (2 times 3/8″)

To many years in school dealing with the metric system means that I suck at working with fractional inches, so I always reach for my handy ProjectCalc Plus at times like these!

The router bit for routing the sticks in the rails is mounted in the router table and set to height using the set up block. Again the fence is positioned so that it is flush with the bearing.

Remeber those scrap pieces of wood. Route the profile in the end of one of them. When making this cut it is important the the rail be kept flat on the table face down and that it remain at 90 degrees to the fence. It is also important that the cut be backed up to prevent tear out as you are routing end grain. There are a number of commercial rail coping jigs that will allow you to achieve this easily. I don’t have one, although every time I build some doors I promise to buy myself one. So what I normally end up doing is to cut a piece of 3/4″ plywood or mdf, making sure that one corner is a perfect 90 degrees. Then I use that sacrificial piece of plywood to hold the rail square to the fence and to back up the cut.

Satisified that the set up of the router bit was correct, I made the coping cut in all of the rails. Remember to make this cut with the face side of the rail down!!

Calculating the size of the panel is pretty simple. Measure the frame opening, then add for the 3/8″ groove all round and then subtract to allow for expansion. With a solid wood panel you would want to subtract at least 1/8″ all round. With the more stable plywood panel that I’m using I subtracted 1/16″ all round. The groove is 1/4″ wide so the undersize 1/4″ plywood fits pretty loose in the groove. However with a couple of coats of paint it should fit just right.

Test fitting the panel.

I like to paint the panel before gluing the door together. That way if there is any expansion of the frame then there won’t be any unfinished part of the panel exposed. This is probably more important with solid wood panels, but it is a good habit to get into.

When gluing the door together the panel is not glued into the groove. Glue is only applied to the coping cuts on the rails. The glue should be done on a flat surface so that the door will be flat and it should be checked for square. I really find the square check for tape measures useful when checking for square.

In closing, and before you head out to the shop to start making a set of doors, I invite you to review a previous post on router feed direction and bit rotation.

October 6, 2009

Making wooden hinges

Choosing and installing hinges has always been a frustrating part of the process of making a hinged box. The array of hinges available is staggering, yet often it is difficult to find just the right hinge for a particular project. I’m also guilty of not planning far enough ahead, and so when it comes time to install a hinge my choices are severally restricted because of the thickness of the wood I’ve used or the design of a particular box. Lastly I’m nervous about mortising for a hinge, messing it up and destroying all the work I’ve put into building a box.

While trying to decide on a hinge for the knife display case, all these factors came into play. In addition I had a lot of details that I did not want detracted from by a shiny metal hinge. I did some research and thought I would try make some wooden hinges. To my surprise I found them easy to make and install. They also looked really nice, and I thought they would add to the overall look of the case.

I milled some maple to half inch thick and 1 3/4″ wide. The width was determined by the finger joint layout, I was using a 1/4″ straight bit in the finger joint template on my Leigh D4R jig. The joints could just as easily made using a jig on a table saw or router table.

Using a 1/4″ round over bit in my router table I rounded over the ends of each piece.

Using the finger joint jig, I routed pins in both ends of one board, and sockets in both ends of the other board.

Each board was then cross cut in half and a test fit revealed a nice snug finger joint. I then pulled the joints apart by about 1/16″ and clamped the pairs together against my drill press fence. The plywood in the image ensured a clean exit hole. It is important that the drill be perpendicular to the table. The entry and exit holes need to be in perfect alignment on each side or the hinge will not open nicely.

After drilling, and before removing from the clamps, I inserted a 1/8″ brass rod cut to length into the hole, and two wooden hinges were complete, ready to be cut to fit and installed.

October 4, 2009

Inlaid half blind dovetail joints

I planned to make inlaid half blind dovetail joints for the frame of the knife display case. The frame is made from African Mahogany and the inlays are tiger maple. This article will show how I made the joints. For more information on the Leigh Jig please visit their website. The article which I followed is one of Leigh’s technical bulletins. Their manuals are very well written and illustrated. Another excellent source for information on the Leigh Jigs is Al Navas’s blog, Sandal Woods.

When making half blind dovetails with the Leigh Jig it is critical to understand the following:

Bit selection is based on the thickness of the pin board.
The bit selected will only produce one specific cutting depth. If you have the bit set to low the joint will be too tight, if you have the bit set to high the joint will be too loose. Only one depth of cut will make a perfect joint.
The pins and the tails are both routed with the same bit.
The scale setting determines how much the pins protrude from the tails. You only want the pins to protrude by about 1/64″ to make for easy clean up of the joint.

The process for making inlaid half blind dovetail joints consists of first making a set of end on end half blind dovetails with two pieces of contrasting woods. Then making a regular half blind dovetail joint where the tails are smaller.

The first step was to prepare the lumber to the right dimensions. While I was doing this I also prepared a couple of test pieces to use in setting up the router and jig and to practice the joint on. I marked all the pieces with white chalk, indicating the sides of the frames (the tail boards) and the front/back of the frame (the pin boards). I also marked the show side or outside of the frame.

As well as the four sides of the frame, I also needed to prepare a spacer board, the inlay board and two shims. The spacer board is used on the Leigh Jig to rest the guide fingers on. The shims are used to help set the fingers of the jig when doing the inlay. The inlay board and shims needed to be milled to a particular thickness. The pin and tail boards are 5/8″ thick and I wanted an inlay of 1/16″ thickness. I was using the 120-8 cutter (router bit) which has a 14 degree angle and a cutting depth of 7/16″.

The inlay board thickness needed to be equal to the cutting depth + inlay thickness. i.e 7/16″ + 1/16″ = 1/2″

The shim thickness was determined by the following formula in the Leigh Bulletin: inlay thickness x 1.28 i.e 1/16″ x 1.28 = 0.08″ (The angle of the cutter bit determines the factor by which you multiply the inlay thickness by in order to determine the shim thickness.

Having prepared all the lumber the next step was to layout the fingers on the jig. As my board was only 2 1/2″ wide there were not going to be many dovetails! It is important to make sure that you have room for at least two shim thickness between each pair of fingers. The guide fingers need to be moved by this amount later in the proceedings.

The assembly is then rotated into the half blind pins mode with the scale set to the thickness of the tail board. The pin board is placed horizontally in the jig and moved forward so that it touches the tail board that is vertical in the jig. You can see in the image below that the tail board is set low enough that the router bit will not touch it!

The pin board is then routed. This is not the normal procedure when making half blind dovetails using the Leigh Jig. Normally the tail board is routed first. For inlaid half blind dovetails the pin board needs to be routed first so that an inlay can be glued into the pins.

The assembly is now rotated to the half blind tails mode and the inlay board is placed horizontally in the jig. It is moved forward so that it is flush with the front face of the tail board mounted vertically in the jig. The inlay board is routed out. When routing the inlay board you need to make sure you route back far enough so that there is enough of a tail to fill the tail sockets.

After making a test fit I took the inlay board to my cross cut sled on my table saw and cut off a couple inches of the end which had been routed. I then glued the inlay into the pin board. As you can see in the image below I did this on both ends of the pin board.

Once the glue had cured, I took the piece to my cross cut sled again and cut the inlay board flush with the end of the pin board.

Now comes the magic trick. With the jig assembly still in the half blind tails mode the guide fingers need to be moved so that the next set of pins and tails that are cut are slightly smaller than the first set. The Leigh Bulletin does a great job of explaining how the guide fingers need to be moved, I’ll do my best here.

The right hand fingers are loosened and moved to the right by one shim thickness. They are then tightened. The left hand fingers are then loosened, slid to the left so that two shims fit between the left and right fingers, then the left finger is tightened. The half pin guides need only to be moved inwards by one shim thickness. The easy way to do this is to move the “spare” fingers (the ones to the far left and right of the joint that are just used to rest the router on) flush to the half pin guides. Then the half pin guides are loosened, slid in by the the thickness of one shim and tightened. The “spare” guides are then moved back out. It sounds pretty complicated, but it is actually fairly simple to do.

Having moved the guides, and with the assembly still in the half blind tails mode, the tail board is routed out. As you can see in the image below the tail board is mounted vertical in the jig and raised so that it touches the underside of the guide fingers.

We’re nearly there!! The assembly is rotated to the half blind pins mode. The pin board with the inlay is mounted horizontally in the jig and moved forward so that it touches the tail board that is vertical in the jig. Again you can see in the image below that the tail board is set low enough that the router bit will not touch it!

The pin board is routed out and finally the inlaid joint is revealed! I don’t need to tell you how exciting a moment this is!

The results of all those steps, an inlaid half blind dovetail joint.

Category: Joinery

Lock-Rabbet Drawer Joint

Building a Flat Panel Door

Making wooden hinges

Inlaid half blind dovetail joints

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