Seat carving with Arbortech’s TURBOplane
Disclaimer: This post is done on behalf of one of my generous sponsors from down-under, Arbortech. The opinions and experiences using their TURBOplane contained below are my own.
Carved furniture can be a very different kind of woodworking. Free-handed removal of material is a completely new experience for me, where I’m used to cutting straight or curved lines with blades. Power carving can be like a messy version of high-speed woodworking in three dimensions.
When teaching yourself how to use any rapidly-rotating sharp tool, starting out simple is usually the best way to go when honing a new skill. This replica of David Ebner’s “Renwick Stool” was a perfect opportunity to give a test run on the Arbortech TURBOplane with a real piece of furniture. Now in full disclosure, this was not the fist time I made tool-to-wood contact with the TURBOplane. I first got the hang of it on a very neolithic looking, low-profile bowl. This will be a part of a future post I’ll be making on a series of carved bowls, and I promise to take you past the neolithic period.
The design of this stool has a carved seat depth of about 1″ from the highest to lowest points, but not all of it is actually from carving to that depth. The highest points of the seat on the front and back ends are actually made by joining two separate pieces that have been cut at a 5-degree angle along the joined edges. This creates a nice lip that can be easily smoothed out by subsequent carving and sanding. The underside of the front and back edges are also eased (from the middle to the outer edges) to a thinner edge of about 5/8″. This was actually the first material I removed from the seat before tackling the seat surface in the next step.
The TURBOplane attaches easily to most angle grinders, and comes with a variety of high-density plastic washers and inserts that serve as spacers between the cutting disc and your angle-grinder guard. The TURBOplane is definitely one of those tools that gets easier to use over time. There is definitely a sweet spot of contact that I found between the cutter and wood that is tangent along the 8-11 o’clock positions. Beyond that, you also have a graduated depth of cut (how much material it removes before it bottoms out past the cutting edge) that you can work with by tipping the grinder at various angles. So users have to think about two dimensions—tangent of contact point as well as angle of attack—between tool and wood surface in order to successfully use this tool.
These two dimensions provide a wide variety of shapes, curves and contours that you can create with the TURBOplane. However, it’s overall 100mm diameter (just shy of 4″) is a bit more limiting on harder to reach places. That didn’t present any problems for this particular project, but for smaller diameters like the inside of a bowl, you’ll need to downsize to the Mini TURBOplane. I’ll cover that tool in greater detail in the future bowl project post.
With the underside of the seat carved to the desired shape, I ran the sides of the leg assembly along the table saw at a 5-degree angle, tapering each side so the leading edge was about 5/8″. This is then shaped with a rasp and files to match the curves of the underside of the seat. Once that is complete, the three pieces can be glued up square ensuring the bench sits flat to the ground and maintains the 90-degree inner angle between legs and seat.
The process I went through to create an even, concave seat was to draw out a grid of 1″ squares across the top surface. At the intersection points of the grid lines, I marked out locations to drill holes. The grid intersects towards the center of the seat received the deepest holes at 3/4″, and then 1/2″ further out from the grid, with the final holes only going to approximately 1/4″ deep. This gives you a reference point for when you begin to remove the material.
I also learned in the process of carving away this material, that like most power carving tools, the Turboplane generates lots of dust. Now the sapele dust always smells a bit like pine, nutmeg and cinnamon, by my lungs didn’t think that was worth the risk. Beyond the dust mask and other protective gear, I jury rigged a few dust collection hoses close by to help collect the stray debris. Best option and my personal recommendation after a few shop clean-ups? Do as much of your power carving outside when possible and let everything blow away in the wind.
Overall, I was able to achieve a reasonably smooth surface with the Arbortech TURBOplane for the seat bottom of this project. It performed nicely along both the concave and convex surfaces, although you to have to address your project a bit differently with the tool to really take advantage of it’s geometry and cutting surface. Seeing how this was my first go at really trying to achieve decent results with the tool, I’m happy with it’s performance as well as my learning curve. I look forward to integrating more free-form carving into my project work outside of this trial run, and think the TURBOplane is the tool for the task.