Hand Profiling a Helical Handrail

Tips and tricks for putting a profile on a spiral-stair handrail using a hand-held router. March 24, 2008

Can anyone give me some information on profiling round, helical handrail? Basic techniques and steps would be great. This will be about 2" diameter, and not exactly true radii. I can probably try to do some sections on the CNC, but that seems pretty time-consuming.

Forum Responses
(Architectural Woodworking Forum)
From contributor B:
We put a bearing guide roundover bit in a hand router and just make four sets of multiple passes (getting deeper each pass) along the rail.

From the original questioner:
What do you do to keep the router from tipping, or cutting too deep, when you get to the point where there is no bearing for the bearing? Do you make a little reverse-profiled guide for the back or top of the piece?

From contributor B:
If I understand your rail profile correctly, there is always support for the bearing. The roundover bit cuts from any side while the bearing travels the center of the rail from that side. What am I missing here?

From the original questioner:
It seems like when I have done this before, on half-round bullnoses, if the router bit is a true quarter-round, then the bearing is slightly below the center line of the profile, and it is trying to move in towards the center of the circle, because there is no bearing where you have previously removed material, causing a less than perfect full-round effect; it looks like a slight ovoid. Am I making sense?

From contributor M:
I made a couple of helical handrails in teak last summer. I did mine by putting a roundover bit into the shaper (it has a router bit adapter), so I could take advantage of having a feeder (feeder tilted up so only one wheel makes contact).

Yes, there was some hand sanding involved, but not too bad. If you decide to use the handheld router approach, why not clamp a guide block to the router base so it's exactly tangent to the bearing?

From contributor H:
With curved rail, it's all time consuming. I have been doing this for quite a while, the way contributor B stated. There is always hand work involved. It is "wood working." The shaper method does work depending on how long your rail is. A 16-20 ft "spring" is hard to keep steady in the shaper. An extra set of hands is very handy also. Trying to do it faster sometimes ends up taking longer because you end up doing it again.

From contributor B:
Yes, I know exactly what you are talking about. You can either hand sand the slight ridge that is left, or put some electrical tape on the bearing to increase its diameter slightly. Both solutions work.