How to Build a Trivet Using a Simple Trammel Jig

Homemade Kitchen Coasters Utilizing a trammel jig and a plunge router, you can make a whole set of intricate trivets in almost no time. If it’s time to purge the scrap bin or you’re just looking for a way to turn your router into Santa’s mechanical elf, here’s a clever little project to try this holiday season. You may have seen “waffle” style trivets before, but we’re giving ours a twist by milling them with a router mounted on a pivoting trammel jig. Stopping the swooping cuts short of the edges of the trivets creates a “captured” one-piece design, or you can rout right through the edges of the blanks and wrap a frame around the routed core as seen on the facing page. I used a 1/2"-diameter spiral bit and 3/4"-wide spacers to form this pattern, but you could certainly experiment with other bits and spacer sizes to produce more unique styles. The only requirement is that the bit be set slightly deeper than half the thickness of the trivet. That way, a series of cuts on both faces opens up the lattice pattern. Once you have the jig built and your blanks made, these trivets are perfect for production-style gift making.
Building the Trammel Jig
[caption id="attachment_4806" align="aligncenter" width="405"]Assembling the Trammel Jig The trammel jig is fairly easy to assemble and, while it doesn't alter router's cutting radius, it allows you to make repetitive cutting patterns very simply. The jig is really simple to build. Start with a 22"-square scrap of 3/4" plywood or MDF, and draw a diagonal line connecting two corners. Cut a 6"-square trammel support from 1/2" scrap and bisect it with a pencil line. Fasten it to the base with glue and brads so the outermost corners of the support align with the edges of the base and the pencil marks of the two jig parts line up. Now rip a pair of 1/2" by 2" fences, cut them to an overall length of 15-5⁄8" and miter-cut one end of each to 45°. [caption id="attachment_4826" align="aligncenter" width="351"]Trammel Support Block Once you've put the mitered ends of the jig fence together against the support block, nail them down to secure them to the base. Butt the fences against the support piece so the tips of the miters touch. Make sure they form a square “pocket” for the trivet blanks to register against before nailing the fences to the jig base. Line the “field” area inside the fences with sandpaper attached with spray adhesive. Later, this will hold the trivets stationary as you rout them. I left the base’s outer corner bare where the trivets and spacers don’t reach it.
Adding the Trammel
[caption id="attachment_4846" align="aligncenter" width="366"]Establishing the Pivot Pint Draw a layout line 12" from the centerline of your bit to establish the pivot point of the trammel. The trammel is a scrap of 1/2" material cut 6" wide and 20" long; this width fit my router base nicely. If your router has a wider base, change the trammel width to suit it. Set the router near the trammel’s end to mark mounting holes for screws, as well as to establish where to bore a clearance hole for the router bit. Mark the trammel carefully with two layout lines: one identifying the centerpoint of the router bit and a second drawn 12" back from this line, before making the bit clearance hole and fastening the router to it. [caption id="attachment_4863" align="aligncenter" width="367"]Setting the Correct Position of the Trammel Slide the trammel along the support block until the router bit touches the outer corner of a trivet blank to set the position of the jig. You’ll need one of your 6"-square trivet blanks to mount the trammel properly on the jig. With the router bit installed, set the trivet blank in the corner formed by the fences and balance the trammel on it and the square support block. Slide the trammel along the support until the inside edge of the bit just kisses the outer corner of the trivet blank. [caption id="attachment_4869" align="aligncenter" width="367"]Boring the Pivot Hole Use the dowel's pivot point line to find where you can bore a dowel hole to complete the trammel. Make sure it lines up evenly over the support before boring a 5/16" dowel hole through the trammel and support — right into the base. Center this hole on your 12" layout line drawn previously. Now insert a 2" length of 5/16" dowel to engage the trammel’s pivot action. You’re nearly ready to start routing trivets, but first, make up 14 spacer strips from 1/2" scrap. Mine were 3/4" x 14".
Making Tricked-out Trivets
After you’ve prepared some snazzy trivet blanks (I tried patterns of contrasting species, glued side-by-side or as two 1/4"-thick face-glued laminations), making the trivets is easy. Set one pair of spacers against the fences so their intersecting ends overlap in the jig’s inside corner. Set your bit depth, and lock your plunge router’s base accordingly. For trivets with stopped router cuts, I drew layout lines 1/4" in from the edges of the blanks to set the starting and stopping points for each cut. Trivets with separate frames don’t need these lines. [caption id="attachment_4870" align="aligncenter" width="475"]Starting to Cut the Trivets Making your first cuts on the trivet face using a pair of spacers along the jig fences and cutting a little deeper than halfway through the blank in the first slot. Start the router and make your first cut, milling to final depth in two passes. I used a 1/2” upspiral router bit — but any sharp straight bit should do fine. Swing the router clockwise or counterclockwise — either works fine, but keep the trammel pressed down firmly against the trivet blank to prevent it from shifting. [caption id="attachment_4871" align="aligncenter" width="476"]Making More Trivet Cuts Continue adding and subtracting spacers and feeding your router clockwise and counterclockwise to make further cuts, but keep the trivet stationary as you pivot the router. Once you complete the first cut, pull the trivet forward, insert another pair of spacers and repeat for the second, longer “swoop.” Continue adding spacer pairs between subsequent cuts until you reach the other corner of the blank. Now flip the blank over, give it a quarter turn to establish the “X” pattern and repeat the whole routing process. This time remove one pair of spacers after each pass. [caption id="attachment_4872" align="aligncenter" width="477"]Continuing on Trivet Assembly Flip the trivet and give it a quarter turn to make an "X" cutting pattern on the second face, continuing to cut them in the reverse of how you made the first side. In minutes, you’ll have your first trivet knocked out and be on to the second. Sand away any bit burn marks or fuzz, and round over the edges. For trivets with frames around them, I used quick-set epoxy to secure the mitered frame pieces. [caption id="attachment_4873" align="aligncenter" width="420"]Final Trivet Assembly Sand away any burns and imperfections and epoxy the pieces together, and the trivet is completed and ready for use or to be given as gifts. The recipients of your curvy kitchen coasters will no doubt appreciate their delicate look ... but secretly you’ll know that the bigger satisfaction — plowing those arching cuts and seeing the pattern develop before your eyes — was really all yours.