Routing stair stringers with the OF1400 and MFS.

A small staircase was needed on one of the jobs I was subcontracted to work on. The company I have used before to fabercate stairs had a six week lead time, that wasn't going to fit the schudle for this job. I remembered seeing in the Festool USA catalog someone was routing what looked like stair stringers with the MFS template...hmmm...I can do that.

The stairs for this job are for a semi finished basement, and the stairs will be painted to match the rest of the set. Time being the biggest factor on this job, it was decided (not by me) to use 2x12 dimensional lumber for the stringers and #1 pine treads because these are stock items. I had to match the existing staircase tread and riser sizes as closely as possible. To layout stairs you need to know the total rise and run, here the rise was a given, the height of the landing the new stairs would butt up to. The run had no restrictions, so I matched the riser sizes of the old.

I needed to get this job done, guys were waiting to install this staircase as soon as I finished it. So sorry, I didn't have a chance to take as many pictures of the project as I would have liked. I used a framing square with stops to layout for the treads and risers first.

The OF1400 is the best choice for this task, I have in the router a 3/4", 1/2" shank mortising bit to match the radius on the nosing of the treads. The mortises will be 1/2" deep, I made the three passes using the turret stops. When doing this kind of template work I use a systematic approach to make sure I don't miss a step. Once the template is moved it is hard to get it back in the right place, so make sure you have the depth right and you haven't missed any spots.

I configured the MFS to rout a L shaped mortise to receive the tread and riser. With careful measuring for the offset of the bit and guide bushing I was able to setup the MFS to make some test cuts.

I made some cuts on cutoffs to get the fit perfect, here the tread is being tested.

With the testing done it was time to get routing! I clamped the MFS to the stringer. There are a couple of things to note here, I used wood strips to act as stops inside the MFS, this would give me the right size slot for the treads and risers. I put packing tape on the bckside of the MFS and wood stops so they wouldn't move. What you can't see in this photo is the angle stops under the MFS to hold the template to the proper distance from the edge of the 2x12. Click on the image above to see a video of the OF1400 routing stair stringers using the MFS template.

With the first mortise cut check the fit, just to make sure. The MFS needs to be kept free of debris to make accurate cuts. Chips can get stuck in the profiles so I used my CT mini to keep everything clean.

Here a look at the first stringer with all the routing done, one down, one to go.

To make the second stringer the MFS needed to flipped over and the angle stops reset, at that point its pretty much more of the same. Oh, I forgot to mention this earlier, after the first tread/riser was routed in, I used a small square to set the MFS, this gave my prefect spacing on both stringers.

As I said, make sure you flip the MFS over to make the second stringer, that way you will have a set, not two of the same stringers.

The tread and risers are cut to length on the MFT.

With the treads and risers cut we are almost ready to test fit. The stringers need some work with a chisel to make the inside corner of the riser and the back of the tread square. And with that out of the way the time of truth has come, will it all fit together......

Well of course it fits, almost perfectly, you guys weren't doubting me were you? With the help of clamps the whole thing went together with no trouble.

To add some strength to the staircase I used Domino tenons to secure the tread and risers. I wasn't be able to clamp the treads and risers so pocket screws were used in place of clamps until the glue dried. The screws were remove before installation to help prevent squeaks.

With the Domino in the upright position and the fence set to account of the offset of the front for the tread and the top of the riser board, I cut the mortises for the front of the treads. Then the mortises for the backside.

Next, I drilled the pocket holes, I had to make sure I didn't drill a hole in the Domino mortise. The next step was to glue all the tenons into the top of the risers and the back of the treads, this saved a lot of time in the finale assembly. It was a bit of a challenge to glue and assemble this thing before the glue set. I really had to keep moving during the glue up so I don't have any pictures of the glueup.

Here is a picture of the back of the staircase, you can see the pocket screw holes.

As you can see here the joints turned out pretty much perfect.

Well, this picture is of the almost finished staircase, the only thing to do is install the cove molding at the top of the riser and underside the tread. This project was done in a few hours and installed the same day, in fact, that was the fist day of the job. You can't get a faster turnaround than that! This is the first staircase with routed stringers I've built, I don't think I would have attempted this project before I had the MFS. After the painters finished the stairs looked great and the clients were very pleased. Not to sound like a commercial but, with the right tools the job is: Faster. Better. Smarter.