While a normal wood lathe has plenty of capabilities in its own right, there's no shortage of accessories to allow you to do more. I've already explored the disc sander so the next logical step seemed to be the fluting jig.
Why a fluting jig? Because you have an indexing head lathe and have never used it... but the most common use is to use a V-tip router bit to carve vertical lines along columns or posts. I wanted to give this a try in pen making (as well as using wide straight bits to create 6/8/12-sided pens with flat faces.
Similar models are on the market already but most are for mini lathes and include the router. Kind of redundant since I've already got a trim router in the arsenal and why buy when you can make it?
Another interesting use is in roughing out large, delicate blanks. By setting the lathe speed extremely low, you can use the router and a larger bit to carefully remove waste from large bowl blanks and similar items.
Step 1: Building the Base
Starting from the bottom, use some 3/4" plywood to cut a base for your jig to sit on. I made mine fairly large so that I have space to work on larger projects, maintain support if the router adds too much weight, and also clear the tailstock.
Cut 6-10" of material to create the stops that will fit within the notch on your lathe bed. These will be glued along the bottom of the base and will hold everything in place later on.
Make another set of blocks slightly larger to go below the first. These will catch the bottom of the lathe bed once they're assembled.
Drill a hole through the top of the base and through both blocks to make room for a bolt. I used 5/16" carriage bolts and matching wingnuts for the top.
Step 2: Building the Router Mount
Moving on from the base, we now need a way to hold the router in place. Most of this was made from the plywood cutoffs from the base. I wanted it to be flexible enough to support different routers in case mine gives out or if I need one with more power later on.
It contains a bottom and two sides with dadoes for stability along with a front and rear support to hold the router. Begin by measuring the size of your router body and making sure your mount will be wide enough to accommodate it, along with enough left over to attach everything together.
Cut a square for the bottom and make 2 dadoes that will hold the vertical sides in place. Similarly, make the dadoes in the sides to contain the front and back supports. Make sure that the spacing does not exceed the length of the cylindrical router body.
With your saw or drill of choice, cut the holes in the supports and ensure your router fits cleanly in place. For extra support, attach some felt feet around the sides.
Glue the sides in place but do not permanently attach the front and back. This will allow us to adjust the height of the router. In theory this won't change, so you can always do it later but I don't like the idea of not being able to switch routers.
To keep the router in place, use a drill press to bore a hole from the tops of the front and rear supports down into the body of each. These will accept the mounting bolts later on. To give them something to attach to, use a larger bit and drill a shallow hole in each side of the lower supports so they intersect the vertical holes already in place. Carefully position a nut in each hole and screw the bolts in place. I used an impact wrench to pull the nuts into the wood so they wouldn't fall out later on.
To hold on to the router, I used some machine handles from my router table. Drill a hole on each side of the base slightly smaller than the threads and tighten them down. After the first test, I realized they were a little long so I glued on an extra plywood standoff as well. These will keep the ends of the handles from digging into the table. It also gives me enough clearance to add nuts into the bottom if the wood threads fail.
Step 3: Iterative Design Considerations
By this point you might have noticed that things have changed in the pictures throughout this project. Since I was designing things as I was building them, this occasionally meant that I had to go back and make modifications.
A few of them:
-The square bottom of the router mount didn't get close enough to the head or tail of the lathe because the head/tail stocks got in the way. I needed to remove the corners.
-After several measurements, I still managed to cut the front/rear supports too short. This ended up working out in the end because I used some shims to very carefully set the height of the router.
-The blocks I cut on the underside of the base were thicker than the lathe bed and weren't able to lock it in place. I needed to use a block plane to remove about 1/16" from them.
Of course, there are also changes I'd make for the next model. Among those:
-Make the front of the base larger so it's easier to move the router for faceplate work.
-Extend the center of the mount base beneath the bit so there's less chance of the bit catching (happened in a test :( )
Step 4: Finishing and Assembly
Once you've go everything assembled, polish the surfaces that will meet and apply several coats of a highly-durable finish. I used wipe-on tabletop varnish and sanded between each coat to keep everything nice and smooth. After that, I added a layer of wax to each surface so the mount glides over the base.
Step 5: Testing It All Out
And that's all there is to it! Time to test things out!
...Of course I had some significant problems along the way. I decided to test my new system with a walnut bowl blank and did some roughing work with the router and then did alternating spirals on the inside and outside. I would recommend starting with something similar but I'd like to know your results.