Finally got around to building a sliding table for making horizontal mortises this past Saturday. I came real close to pulling the trigger on the MLCS horizontal router table with mortising attachment but decided to give this a try first. I actually copied a lot about the MLCS design. I was mainly looking for a way to easily setup and do loose tenon joinery, and didn’t want to purchase a Domino. At some point in the future when making raised panels I may wish I had the horizontal table, but this solution works very well for making the mortises. I was surprised how well it worked actually, and the cuts were much better than anticipated given the slower rpm of the Shopsmith vs. a router (and a badly burned old upcut bit).
I’ve got two Shopsmiths in my shop which I picked up dirt cheap over the years. The 10ER is primarily dedicated as a lathe and occasionally used when I need a scroll saw. The Mark V spends most of its life as a belt/disc sanding station. I had been thinking about how I could take advantage of the Shopsmith and some of the features that would work well for the mortising function. The unit makes a good horizontal boring machine and their site demonstrates some methods for slot mortising but it didn’t provide exactly what I was looking for. I already had the router bit chuck. The table can be easily and smoothly adjusted for height so the mortise position can be precisely positioned. The bit can be very easily plunged using the quill feed lever and has an adjustable stop for setting the correct depth. I found I could easily keep one hand on the quill depth lever and use my other hand to slide the sled back and forth. Tightening the quill lock just enough to provide some friction even seemed to keep the bit at the correct depth without locking or keeping my hand on the lever.
The photo of the bottom of the sled shows a short section of T-track on each end between the miter bars. The thumbscrew stop on each end is adjusted to provide for a precise stop for the length of the mortise. Other than the stops on the bottom, it is setup and functions similar to the demo on the MLCS website.
I’ve got some “slick strip” tape and aluminum angle on order. I’m going to mount that along the edge to create a 1/8” high fence to register the wood against, and the other edge will wrap under and ride against the bottom of the shopsmith aluminum table. That should provide a little extra safety and prevent the sliding table from being able to lift up and off.
Now I’ve got to make some loose tenon stock and find the time to start a project.