A couple of people asked me about this jig during my shop move, so I figured I'd do a quick writeup. Can't do any woodworking for a while anyway.
My lunchbox planer snipes. It’s very slight, and usually I can just sand it out. Or, if I have enough material, I’ll just cut my stock long and then simply trim the sniped end. But when I’m making something like an end-grain cutting board, snipe is an absolute no-no. To compensate for the snipe, I created a sled that provides a leading edge for the board. The edge consists of a piece of plywood with a thin sacrificial strip of hardwood that will be planed along with the work piece. This means the edge receives the snipe instead. Most people know about this technique, but I've never seen a jig that makes this easy to set up.
The sled is made out of ¾” melamine, 12” x 36”. Plywood would also be a good choice. The width should match your planer. You can make the sled any length, but 36” can handle reasonably large pieces without becoming unwieldy.
First, route ¼” holes along both sides, 1” in from the edge and 1” apart. Each hole should be ½” deep. These holes will receive the "stops".
Next, create “stops’ using ½”, ¾’ and 1 ½” plywood (the latter is made simply by laminating two pieces of ¾” plywood). Each stop should be 3” wide and about ½” narrower than the sled, in this case 11 ½”. Drill two ¼” holes into each stop, ½” deep. Glue ¼” x 1” dowels into these holes. The distance between the dowels should match the distance between the routed holes in the sled. Use dowel points to ensure the stops fit snugly in the sled.
Note: For the ½” stops, you will have to trim the dowels since the ½” plywood is only 15/32” thick.
If your planer only snipes at the beginning or the end, you only need one stop for each thickness. If you have both snipe at the beginning and end, you’ll need two stops (as shown in the last picture).
When planing a board, determine the right stop to use. If the final thickness is to be ¾”, use the ¾” plywood stop (which is actually 23/32” thick). Next, use hot melt glue to attach two thin strips of hardwood to the stop. The combined height of the stop and strip should be about 1/16” over ¾”. Secure the board with a couple of drops of hot melt glue as well. Double sided tape can also be used. (In the picture, I put a bit of oil on the strips to make them easier to distinguish).
Now run the sled with the board through the planer. The stop with the sacrificial strips of hardwood will engage the rollers before the work piece, and receive the snipe instead. If your planer has trailing snipe as well, attach the second stop at the end of the board. Note that this does reduce the capacity of the sled by another 3”.
Once the board is planed, you can easily pop off the strips and replace them with new ones. My shop never seems to have a shortage of thin strips of hardwood, there’s always a leftover piece that’s useless for anything else.
Tips:
-To make it easier to remove the strips, seal the stops with polyurethane or apply some clear packing tape. Wax is not a good idea since it will interfere with the hot melt glue.
-With some extra holes in the stops, you can make them stackable if you offset the dowel holes. This allows you to stack the ½” stop on top of the ¾” stop, in case you need to plane a board down to 1 ¼”.
-This sled doubles as a simple planing sled when a board is too wide to face joint in the jointer.