So normally when I want to do/build something I haven't done before I always ask the internet first. Because I'm sure someone has been thinking about it for a long time. Since there was so little information out there about this technique, I thought i'd blog about it for the next guy who is up against this task.
So my house has a small wrap-around porch on it. And when I got the house it had a set of pressure treated spindles forming the railing. While they were accurate for height, they were an off the shelf spindles/rail set that weren't very victorian as seen here.
During excavation of the crawlspace I had a lucky find. When the original spindles were replaced, a handful of them were thrown under the house! I found about 20 or so of the originals though badly rotted, a few seemed in good condition under the paint. They were definitely the originals because the pattern on them matched the small spindles at the top of the porch. They also were cut from thicker stock as compared to the modern day mass produced ones.
Mind you now this rail has been missing for at least 36 years as they are missing from this 1976 photograph.
So I set out to rebuild this railing from the savaged parts I had. The tough part was that I had about 3 good spindles from the lot I found and I would need OVER NINETY to complete the project.
I looked over options on how to duplicate them. One option is to buy a duplicator. These contraptions are very expensive starting at the bottom $300. They also cut slowly and you still have to tune your turning up by hand afterwards.
I found a few people on the internet who made duplicators with carbide knives, but nothing that was going to expedite my process. Then I found a few notes about cutting them with a router. Now at first thought this seems like a very bad idea. Having two things spinning at high speed at different angles coming into contact with each other sounds like a bad idea-and for the most part it is. But that is why a lot of development and precaution went into this process.
Anyhow lets get to it.
First off the stock. It is 8/4 poplar. Since they are painted they don't need to be anything fancy. Unfortunately spruce/pine/fir and other softwoods don't cut great on a lathe. It requires you to always have super sharp tools and are not very forgiving if they blowout. So poplar being the cheapest hardwood that paints well was my choice.
Next I cut them into slabs with a circular saw to make them manageable at the table saw. Each slab is two spindles long and 4 wide yielding 32 spindles per board.
Then the boards are ripped down to their final dimension of 1.75"x1.75". These boards started out a little cupped, so they required a little more attention at the table saw. If you don't watch out this could result in some trapezoidal blanks. One other note here is that I had some serious binding from internal stresses on my blade. A riving knife would surely help prevent this, but since I do not have one on my saw, I would drive a wedge in the slot past the blade to prevent this condition as seen in the photo.
Now that the blanks are cut to the final size I like to take one more step before putting them on the lathe. Because removing material while turning takes a lot of effort, i minimize this by setting up a jig on my chop saw to make some initial cuts where I know I will be hogging out material. I have my saw set up with a jig to accept the spindle at a 45degree angle lengthwise. The chop saw is tracked out to have the spindle length and the depth stop is calibrated to prevent the saw from going to deep. Then I make eight cuts (4 in each direction).
Then as you would turning any project, I find the center of each blank with a center finding tool and tap a small indent in with a punch to make it easier to locate on the lathe.
After that it's on to the main event.
So there are a lot of things to note about this that I don't mention in the video. First off this can be very dangerous. If you don't have sharp bits, or a stable rig or if you move too fast the router can get 'pulled in/across' the work piece. You must move slowly and get used to the feel when you do this. Along those lines I'm running the lathe VERY SLOWLY. I have a multi pully lathe, and then a Variable speed control on top of that bringing the stock speed down to 200rpm. At the same time i'm running my router at max speed of 25000rpm. The router seems to cut best when it is plunging into the work. You can see in the video that I make multiple plunge cuts before pulling the router across the work for the final form. While you can move sideways, it is a much slower operation. Also note I can only move left to right because of how the bit cuts. Moving right to left would drag the router which is momentarily seen at time 2:40.
And here are some on the house.
Overall this is a very effective way to duplicate spindles. I had previously tried a design i made based loosely on the pantorouter that looked like this. But there was too much slop in the linkages and was not as accurate as I desired so it was scrapped.
Other designs that appear to be real effective are the teen woodworkers Router Lathe and the badassed FLOATING ROUTER!