Technical Thursdays - Coasters and Placemats archive
Thursday 3 April 2014
Anthony Bailey makes table top accessories with a mini router tableError loading Partial View script (file: ~/Views/MacroPartials/cwsGalleryImages.cshtml)
The projectWhen you have a dinner party, or just a meal, don't spoil the table top or table cloth. Protect them and make a feature by having proper placemats and coasters which can also find their way in to the lounge when you are relaxing with a coffee or a glass of wine. All you need is some good quality ply, in this case birch ply or sapele-faced MDF, a tough lacquer or varnish to protect it and some offcuts of MDF to make templates.
The jigSTEP 1
To make these items we need to make simple MDF templates for accurate shaping. However, this gives me the perfect excuse to make a mini router table for a DeWalt Twin Base router. It has plenty of power, comes with a plunge base and a fixed base that the motor can is screwed up and down inside, and is quite compact. This table would also suit the Bosch Palm Grip router, or any standard laminate trimmer. So long as you can still adjust the cutter height, any machine of this type will do the job nicely
The machines are not really designed for inversion, so the first job is to remove the baseplate screws and the baseplate itself - don't lose them whatever you do! You will need longer machine screws of the right thread type. Don't assume the thread is metric; you may strip them, which is not a good thing
Choose a 9mm offcut of ply for the table top. It doesn't need to be large as we are only asking this setup to do smaller work. Use another, longer, board as an upright to clamp the table in your vice and to fix the router table to. Glue the two together at a right angle with a batten in the corner to give it strength. The batten needs to be shorter to allow for the vertical brackets that will be fitted next
Now glue two brackets into the resulting 'L'-shape, inboard from the ends, leaving space as we need to leave room for clamps which will hold the fence in place. These can simply be butt-glued in place
Make up a fence in a similar way to the table, but with four brackets - two of them need to be either side of the cutter opening to form the basis for an extraction port, to which a pipe can be fitted later. The fence can be clamped to the table easily and accessories parts clamped to the face of it
Mark the table surface in the middle where the mounting holes need to be. Do this with some care as the rather small holes could easily be out of line and prevent the router from fitting. Drill and very carefully countersink just enough for the screw heads to lie below the table surface
Once the fixed base is successfully bolted into place, fit a large diameter straight cutter with a bottom cutting insert into the router collet. You can push the motor can into the fixed base so it snaps into the winding collar - in the case of the DeWalt - and wind it up with it switched on and machine a hole through the table, which is now ready for use
The cuttersJust two cutters are required this time. A 19mm straight cutter for making the templates and the cutter hole in the router table top and a 12.7mm bearing guided straight trimming cutter for shaping the workpieces accurately.
Making itSTEP 1
Decide what size and shape your coasters and placemats need to be, and make 6mm MDF templates to suit. All the primary cuts must be accurate and smooth, preferably done with a router, straight cutter and guide, or on a sawtable with a crosscut blade. Any rounded corners need to be done accurately and as identical to each other as possible. Use a fine tooth handsaw to remove most waste then a wood file or fine rasp, finishing with medium abrasive paper so you end up with smooth shapes to use as templates
Round coaster or placemat templates can be made up using an inboard trammel. You will only need one of each template, of course, but you can then make as many coasters or placemats as you want
Make sure the blank or blanks are slightly larger than the template you have made by about 2-3mm. This will ensure you have enough to machine away without straining the router too much
Use double-sided tape to fix the template to the blank, centring it so there is an even amount of waste area all round
For templating, the straight fence isn't required, but you do need to make up a batten with a rounded lead-in 'nose' to act as a safe feed-in to the cutter itself. It must be firmly clamped on the table and close to the cutter so you push the workpiece into the direction of cutter rotation. Note the clear Perspex safety guard on top
A bottom bearing-guided trimming cutter is mounted in the router. Move it up through the table using the fine adjustment facility to align the bearing so it will run against the template, ensuring the cutters are high enough to completely trim the edge of the workpiece
Press the template and blank combination down on the table with the template on top. Remember you must feed from your right and push along to the left of the cutter so you are moving into the direction of cut. The lead-in point will prevent you from accidentally going to the right of the cutter which would cause the workpiece to be thrown to the side.
Placemats and coasters need a protective coating, such as a heat and moisture resistant lacquer. Use several coats, flatting off in between
Use self-stick flock sheet on the undersides to protect table tops. Cut it oversize and stick it on, then turn it over and trim carefully along the sides of the finished coaster or placemat
When the job is done, you can use your newly built mini router table and fence for all manner of routing tasks!