Puzzle joint to combine 2 parts of stair stringboard

In partnership with Maxicam we offer a complete software to CNC solution that includes our cabinet software Polyboard, nesting optimisation software OptiNest, VCarve and of course a 3 axis CNC.

This configuration is optimised for nested based furniture manufacturing but if we add our stair software StairDesigner it can also be a great solution for general stair building.

Stringboard Management

One of the annoying problems that arise when building stairs is that one often finds oneself with strings that are longer than the bed of the CNC. This is of course the case if your CNC is a smaller model but can also arise even when you have a CNC with a 4m bed as it’s not rare to have strings up to 5m long.

Here is a typical case where a simple straight stair requires 2 strings of 4m50 long.

To machine these stringers on a CNC with a bed of less than 4m50 we have 2 possibilities, either machine in 2 operations moving the stringer on the machine or make the stringers in 2 parts.

If there is enough space either side of the CNC it’s always possible to machine one long string with 2 separate programs by sliding the string along the machine bed. This requires having a straight edge and some precise positioning points so that the 2 machine programs will align.

Puzzle Joint Solution

A simpler solution is to use the CNC machine to cut the stringer in 2 separate parts and join them with a puzzle joint.

Stringer in 2 parts with puzzle joint

This solution has several advantages:

  • Firstly, it is not necessary to align the stringer to each separate program and each part can be cut and calibrated separately.
  • And secondly it’s much easier to prepare the wood 2m30 long rather than 4m50.

A board of 4m50 x 300mm can get heavy and cumbersome and if you have ever tried to assemble and plane up accurately such a board on a jointer and thickness planer you’ll know what I mean!

Because of its amazingly accurate cutting, a CNC allows us to cut joints that would be near impossible or at least tricky and time consuming to cut buy hand.

In this video we show how to draw the puzzle joint in CAD and prepare the StairDesigner DXF drawings for machining in VCarve.

As you can see using the correct methodology this can be quick and efficient and long strings can be made very easily on a CNC with a smaller bed.

In this second video the strings are cut and machined on the CNC, including the puzzle joint. The completed stair with a very neat puzzle joint in place is also shown.

Affordable Manufacturing for both Stairs and Furniture

So whether you build furniture or stairs or both, a 3 axis nesting CNC offers an affordable solution with minimal space requirements. At the same time, it will allow your company to manufacture much more effectively in today’s competitive marketplace.

With our partner’s Maxicam, we offer the entire start to finish workflow in house. Our focus is very much on providing a complete solution for your business, not just the software or CNC in isolation. And all fully supported of course.

Please click here to view our specialist woodwork CNC machine configurations and contact us for more details.

    4 replies to "Stair Building made easy with a 3 Axis CNC Machine"

    • Jessica Darcey

      Great idea and love the puzzle joint.

      • Stefan

        Thank you very much for your message…

    • Linda Brandon

      Great solution! do you feel there is any issue with using more than one puzzle joint per stringer? i have a 2×3′ bed on my cnc

    • Ness tillson

      No problem to have several joints on the same stringer.

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