Custom Stair/Handrail Components

[moehink@ieee.org]

I don't own a CNC machine (yet), but I have been wondering whether it could handle custom handrail pieces. I am just finishing a staircase project that included several custom made handrail components. Instead of using standard components (goosenecks, easings, etc.) I laminated thick stock and cut appropriate curves in top and sides to create a custom 3D "connector" between two handrail sections. For anyone who is familiar with "tangential handrailing" this is essentially the same concept. After cutting the basic shape, I routed the profile, which can be a real challenge on stock that is curved in 3 dimensions.

Based on my limited CNC knowledge, I believe I would need a 5-Axis machine to cut the shape and rout the profile along its length. I noticed the ShopBot prototype 5th axis on the Jamboree page, and was wondering if this would handle the application I have described. Obviously I would have to keep extra stock (or temporary "legs") on the piece so it could be fastened to the table during the routing process without the risk of rocking.

Sorry if my question is long-winded and confusing, but the components are difficult to imagine and harder to describe. Please let me know if anyone has an opinion regarding the feasibility of this idea. I am also curious if a availability date has been defined for the ShopBot 5th axis. Thanks.

[rgbrown@itexas.net]

Craig,

You are correct in saying a stair rail is a complex piece of carving. I do not think it is something that will require a 5 Axis machine. To build as you described "and rout the profile along its length" probably would take "a 5 Axis Machine".

A 3 Axis machine can easily carve anything it can reach "From the top". By properly indexing the part, any view can be the 'top'.

Another 'way' might be the 4th Axis. And to further confuse things, someone creative with tool paths and a good 3D modeling program can define tool paths that can cut simply amazing things.

Many of us dream of the 5 Axis, make anything CNC machine. Few of us have the software and knowledge to program one of the devils. When I win the lottery, I'll have my secretary tell everyone how nice a 5 Axis machine is and have her brag for me on how easy it is to program. I can hear me saying "Fire that SOB and see if the next guy can program that damn thing", after the third or fourth employee the machine ate.

Ron Brown - rgbrown@itexas.net (mailto:rgbrown@itexas.net)

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