Lee Valley & Veritas
Woodworking Newsletter
  Volume 8, Issue 1 - September 2013    
Table Top Fixing Blocks
  Four different methods of attachment
Tabletops can be attached to skirts (often called aprons) using hardware such as Z-shaped metal brackets that slip into a narrow kerf made inside the skirt. They can also be attached using figure-8 shaped fasteners, which are screwed onto the top of the skirt after boring shallow holes to accommodate the heads of the fasteners, while the other ends are screwed under the tabletop. Another method is to use 45° metal brackets screwed inside the skirt and under the tabletop. Finally, you can use shop-made wooden clips. (All four methods are shown from right to left.)

When using the traditional method of wooden clips, they are screwed under the tabletop and embedded into mortises made inside the skirt. The best way to allow for natural wood movement is to mill slots into the wooden clips as well as to not over tighten the fixing screws. To further refine the look of your project, you can mill stepped slots to conceal the screw heads. Here's how to do so.

Milling Stepped Slots
  Making the guide
First make a template guide to mill the stepped slots. Take an approximately 6'' sq. scrap piece of 1/4" hardboard, MDF, HDF or Baltic birch plywood (which has no voids) and glue and nail it to another scrap of 1" x 2" that will act as a fence. Let the glue cure.
  Setting the bit height
At your router table, chuck up a 5/8" two-flute straight router bit and set it for a one-pass cut, as shown. Since the slot is short, the router bit won't have time to build up much heat.

If you plan to use a guide bushing larger than 5/8", use the appropriate sized router bit.
  Setting the fence
Draw a center line on the piece of 1" x 2" (approximate size) hardwood that you're using for the wooden clips. Drop the template onto the router table, keeping it against the fence. Move the fence until the center line of your stock is in line with the center of the router bit and lock the fence down.
  Setting up the stop blocks
Install one (or two) stop blocks and have your push stick handy. I installed just one stop block, since only one pass was needed and because the slot length is arbitrary. Refinement has its limits, I believe! If, however, you're not comfortable doing it by eye, use two stop blocks, one on either side.
  Plunging the bit through the template
Hold the template at an angle against the right end stop block (shown in previous picture). Turn on the router, slowly plunge the template onto the bit, slide it to the left about 1" and turn off the router, waiting until it completely stops. If you're satisfied with your new template, cut off the thin corners or sand them round. Drill a small hole to hang it on the wall.
  Marking out the slot
At the workbench, mark the beginning of the slot, about 1/4" from the end. The template will be used to determine the entire length of the slot.
  Positioning the template on the workpiece
Place the workpiece with the mark flush with the end of the template slot. It is held down between one jaw of the bench vise and the fence of the template. Keep the template flush with the bench top for added stability and to prevent it from flexing. This 6" square base is the perfect size for the router to ride on.
  Two routers fitted with different sized guide bushings
Here is where two plunge routers and two identical guide bushings come in handy. One router is fitted with a 5/8" guide bushing (earlier I used a 5/8" router bit to mill the slot in the template) and a 3/8" straight router bit to match most screw heads. The second router is also fitted with a 5/8" guide bushing but with a 3/16" carbide spiral bit, which is more than enough for most screw shanks.
  The first milled slot
If you're using only one router, rout the first step of each slot with the 3/8" bit and then rout the second step with the 3/16" bit. You will have to relocate the template guide, but each location has been marked, so it should be relatively foolproof. Make the 3/8" step first, deep enough to conceal the screw head. The second pass is a through cut with the 3/16" bit. For this application, I appreciate the design of the Kreg® pocket-hole screws, with their washer-type heads and self-tapping tips.
  Multiple slots cut
After milling the first slot, take the time to establish where you will mill the tongues or tenons. Mark the starting point of the next slot and repeat the process all the way down the workpiece.
  Cutting the tenons
At the table saw, cut the tenons using the saw blade or your dado blade set. A board screwed to your miter gauge will help to safely support this long and narrow workpiece.
  The individual blocks
  The blocks in use
Finally, the miter saw (or the band saw) is both secure and well suited for cutting off the blocks.

To secure the blocks, each screw must be driven into the middle of the slot and the blocks fully embedded in the apron's groove. They should be close to the legs but not leaning against them so that the wood can feely expand and contract (mostly sideways) with changes in temperature and humidity.

As you can see, you'll end up with quite refined attaching blocks to secure tabletops to skirts. This is an easy way to emphasize your craftsmanship, and the time invested in making such refined parts is minimal in comparison to the pride you will take from your work.
Text and photos by Serge Duclos

Serge Duclos started woodworking 40 years ago after purchasing a house. He soon found it was a way to relax from the stress related to his job as a human resources professional. Since retiring in 2004, Serge continues to enjoy his pastime and to update his bilingual woodworking blog http://atelierdubricoleur.wordpress.com with his projects, as well as his tips and techniques.
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