Wooden CNC

[Neale]

Lots of comments made with the best of intentions. It won't be popular, but I'm going to put a different point of view. I built my MDF router to the JGRO design around three years ago. It's a pretty poor machine by many standards. However, I originally built it to make an engraved plaque for a presentation, about 20"x16", with some nice lettering and a relief picture in the middle. It turned out OK. Since then, I've helped my son with an architectural project profiled from 18mm ply. All the bits cut and fitted together as drawn. I've engraved nameplates, and lots of other odds and ends (like profiling 25mm sapele about 600mm long) in between. So, why am I building something bigger, faster, stronger? Because it is slow, it bends and vibrates if you push it a bit, I used M10 studding with home-made anti-backlash Delrin nuts as leadscrews and the X leadscrew flaps in the breeze above about 900mm/min when cutting wood would be better at ten times that. The MDF moves with changes of humidity and it's near impossible to keep the bearings adjusted. And so on.

But, as I said, it does work. This is a hobby machine, so don't judge it by commercial standards. If you are doing fine engraving, top speed doesn't matter a jot as you'll never reach it - acceleration for all those changes of direction is much more important. Studding is cheap, even compared to multi-start trapezoidal screws. It's pointless thinking about ballscrews as the machine structure won't take the cutting forces involved at the speeds they would allow. I often hold work on small blocks machined in situ to give accurate alignment, even though the bed isn't all that flat. Jobs can take a while, so I get on with something else while the machine is running. In other words, I can work around or live with many of its limitations. I'm building a new machine in steel to overcome these problems, but that's at least in part because I love building tools and machines.

I wouldn't recommend, generally speaking, that someone builds a wooden machine, but everyone's situation and needs differ, so there's a place for them. Don't be put off by people whose needs and resources are not the same as yours. You might find more uses once you have a machine in the workshop; that might help you identify a replacement in due course. Pity that you are at the other end of the country or you could have had a warts and all look at a wooden machine and things made on it.