First published – 30 June 2017

For those lucky enough to have a CNC machine in the workshop – this is the way to scarf and cut your plywood!

Andre from Australia is building the small boat “Noosa” in his workshop in Melbourne and sent me these pics of his progress so far, kindly allowing me to share them with you.

Andre has a CNC router in his workshop and is using it to make his boat – with precision. It took him a little while setting it up, it was the first time cutting plywood with his machine, but once everything was ready, it took just 2 hours to cut all the parts of the boat.

ply parts ready to cut - CNC

Using dxf files eliminates the following steps;

        Scarfing the plywood sheets beforehand is no longer necessary. For hull parts that are longer than a plywood panel, the parts are cut in sizes small enough to cut from a plywood panel or to fit the machine.

Finger joints are cut on the ends of the pieces to join them together, instead of grinding feathered edges and joining plywood panels to make them long enough. This eliminates a job I was always happy to get behind me — scarfing the full-size panels of plywood before marking out. It is often possible to make more efficient use of the wood too.

        Drawing the parts to be cut onto the plywood is no longer required. The dxf files provide the machine with the dimensions. This eliminates drawing the parallel lines across the plywood, marking out and joining the dots and tracing out the parts. No batons, no lofting, no mistakes.

        You don’t need to cut the wood either. Another time-consuming job, carefully cutting along the lines that you have marked out. The machine does it super accurately and much quicker than you can. The resulting parts are perfect in shape.

It is brilliant and very precisely done as you can see in his photos. Hats off to Andre, well done.

It is not likely you would buy a machine like this, just to make a small boat like Noosa, for a one-off job. But if you have one there already, or know someone that has a machine, it shows how cool the technology is that’s available today and what is possible even at home. I must admit I am jealous! A CNC router is definitely a tool on my wish list, for my next boat build… 

Like 3D printers, the price is coming down, and the performance is improving almost day by day. Kits and DIY ways to make a router are also appearing – so you can automate and do with precision at home, what was up until a few years ago, only affordable in the industry. For a project like building a big yacht, it is something more than worth thinking about, it is probably an essential bit of kit these days. 

Cutting intricate shapes in plywood is a time-consuming job and is a large part of the build, in both small boats and large ones. For making everything from temporary hull frames, hull panels, to bulkheads, to the interior joinery on a bigger boat. 

It also eliminates the need to print or plot from drawings, and then to have to transfer the shape on to wood before cutting it out. With digital files, the information is sent straight to the CNC machine, saving time and mistakes.

Update – 12 April 2019;  Things move fast. It’s nearly 2 years since I wrote this post and in that time it’s gone from the odd enquiry back then about CNC files, to now receiving enquires almost weekly. So, from this week onward, CNC files will be available as an optional extra to any plans on this website. 

There is a learning curve, and it takes time to get set up, but once you know what you are doing you can really save time down the track, and everything is cut to perfection. Great work, Andre. ?

Thanks for reading,

Tim Weston