Lately I’ve been dreaming about a few Japanese machines that are really well suited for kumiko work. There is a potential project on the horizon involving some large and intricate kumiko panels, which has got me thinking about using these machines to make the work more manageable.
Mini Forte Thickness Planer
First up is the Mini Forte Thickness Planer. I first came across this planer years ago when doing some searching for kumiko related info on google. The company that makes this machine has ceased production a long time ago, but among folks that do kumiko or small furniture projects, this planer is somewhat legendary for it’s ability to accurately plane stock ridiculously thin.
My understanding is that this is a pretty robust little machine despite it’s size. The website where I pulled off the images posted here describes doing a bit of repair to one machine that is from 1985, and from what I can tell a few new parts are still available, which is good to know.
The feed rollers on this planer are pretty close to the cutter head, which is what allows it to plane material to usually impossible thicknesses. The picture below shows some 0.5 mm thick material after planing. That’s impressively thin!
Most planers made today have a limit to how thin they will go. My old Ridgid planer would only go down to 1/8″ or about 3mm. I’m sure a lot of you are probably familiar with the usual trick used to mill thin stock on planer that has a limit. By creating some sort of plywood platen that effectively raises the bed height of the machine, you can plane stock thinner than the machine will go. The problem is that many planers still have the tendency to devour and destroy material beyond a certain point. I could just barely get away planing 2mm (about 3/32″) stock on my old Ridgid planer, and had the same experience when using a Dewalt DW735. The feed rollers are just too far from the cutter head, so when the wood becomes thin and flexible it tends to get pulled up into the cutter. The result is a major loss of material on the ends of the stock.
So thinking about the need to mill LOTS of thin little kumiko strips, and not wanting to waste the last 6-8″ of every piece, the Mini-Forte is starting to look really tempting.
Hitachi Baby Supersurfacer
This is a machine I’ve been dreaming of for a long time. For those unfamiliar with supersurfacers I suggest you check out this video. Supersurfacers are essentially the machine version of a handplane, and they are truly awesome. I briefly had an old Hitachi supersurfacer back in NY, and though I barely had a chance to use it before we moved to Japan, it was a really cool tool. I don’t think I’ll ever give up my hand planes, but I can see the benefit of using a supersurfacer for making kumiko. For small kumiko projects using a handplane is fine, but if you need to plane a huge quantity of kumiko then a supersurfacer makes a lot of sense. And what better than this little Hitachi model PF 60 F2 Baby Supersurfacer.
Here’s a quick little video showing this machine in action.
It’s pretty simple as machines go. Essentially just a rubber belt that shoots the wood past a blade. For kumiko and shoji work, I’ve seen these used to not only finish plane the material but also fine tune the thickness. It’s a pretty handy little machine and they are plentiful on the used market here in Japan. I know of a few floating around the states too.
Sliding Table Radial Arm Saw
Last but not least for this short series of kumiko dream machines, is an indexing radial arm saw. Before we get to the really good stuff, here’s an old version of a saw designed for kumiko work. This isn’t a radial arm saw, rather it’s more of a sliding table saw, but one big step in the machine kumiko work direction.
There is currently one of these available on Yahoo Auctions for only ¥5000! The saw in the video is pretty old and crusty, but has some cool features such as the preset depth setting and the little plunging mechanism that allows you to do….. actually I’m not sure. It must have a very specific function but I’ve never used one of these machines, so I can’t offer any insight from real world experience. That said as crusty as this saw is, it looks to me like it would be really handy for cutting 90 degree half-lap joints for kumiko work.
Another interesting series of saws that are largely designed for precise crosscutting work are the Petty Work line of sliding table saws. These saws aren’t necessarily designed for kumiko work, but they could certainly do the job, and models like the Petty Work 300 WS have a long table for supporting long kumiko, door rails/stiles, etc.
But the real dream machine is an indexing sliding table, radial arm saw. These saws are really cool. The radial arm saw itself is made to be incredibly rigid so that flexing is not an issue, and the table slides left and right, and can be set to stop at specific points. That allows you to clamp a whole batch of kumiko to the table, and then move the entire table relative to the saw for really precise cutting. The saw head also pivots allowing you to cross cut at different angles for diamond and triangular pattern kumiko grids.
Check out how massive the sliding arm setup is on this saw.
These saws take up a lot of space, and currently owning one is far beyond the scope that I can handle both financially and size-wise, but someday a machine like this would be a real joy.
The modern version of this type of machine is computer controlled, allowing you to basically program in the exact width of cut and spacing between each half-lap joint.
Before moving to Japan I seriously contemplated making my own kumiko saw, using a radial arm saw and cobbling together some sort of sliding table with parts from McMaster-Carr. But the weak link is really the radial arm saw. Any tendency to flex side to side or up and down as you move the saw makes for a poor cut. I still think it can be done, but it would take some digging to find a radial arm saw that can cut accurately enough for something as fine as kumiko work.
Thanks for reading and hope you enjoyed this quick look at a few unique machines from Japan.
Thanks for this post. I’ve always wondered why big Japanese manufacturers like Hitachi haven’t developed and marketed versions of these machines for North America. (I might put groovers on that list of machines I’d like to see here). I suppose because of the different level of surface finish demanded in the different markets, and of course, cost.
The hassles of finding Japanese machines like these and then adapting for the change in voltage is also daunting to most of us.
A super surfacer is on my “when I win the lottery” list. I have read that to get the most of them one also needs to get a knife grinder accessory and that is a stumbling block since now you have to buy two machines. Not a problem when you win the lottery!
I’ve often thought the same thing regarding these tools being limited to the Japanese market. Super surfacers from Hitachi were briefly sold in the US, but I think the complexity and finicky nature of the machines really limited their sales… at least that’s my guess. Groovers also have a somewhat specialized function that I think is pretty limited outside of traditional woodwork in Japan, and I also imagine that they probably don’t meet OSHA standards with a complete lack of blade guard.
I really can’t speak to the voltage differences/issues between Japan and the US or other countries, but I’m also really curious at what level it becomes a concern. I’ve used quite a few 100v Japanese tools (circular saws, planers, supersurfacers, etc.) in the US plugging into 120v outlets and there were no noticeable ill effects. And I know of several people who have been using 100v Japanese circular saws for years in the US without issue. But this is something I’d really like to learn more about especially in regards to larger machines running on higher voltage.
Sharpening is a big issue with super surfacers and I imagine that’s partly why they never really caught on outside of Japan. There are now several makes/models that will take replaceable blades which eliminates the need for a dedicated sharpening machine, but that also is an ongoing expense and can be tricky to order from Japan. That’s the route I think I’ll be heading though. The little Hitachi super surfacer I posted about here, has an option for either a blade that requires sharpening or replaceable blades, and I’m going to opt for the replaceable blades. That said investing in a sharpening machine is also tempting since it could also allow you to sharpen your own planer/jointer blades.
Another great read thanks Jon
I visited a kumiko workshop in Saga, Kumamoto and they had a magnificent computerised sliding table saw, at a magnificent price. Well worth dreaming about though.
As an amateur kumiko maker I’m interested in thicknessing machines and my friend has a German one which he uses for mini-furniture making (1/12th scale). Supposedly this can be set to remove parts of one millimetre, but I don’t know about the thinnest dimension possible. This alone would be a welcome step forward for someone with my skills
Cheers
Keith
“a magnificent computerised sliding table saw, at a magnificent price” – haha I can believe it!
I would love to take a tour of that shop in Kumamoto, that must have been a cool experience. With computerized machines like that, I suppose a lot of the wood milling/cutting becomes simplified to the point that the majority of the labor involved simply goes into assembling the screen. Which probably still takes a considerable amount of time especially for really elaborate designs with tons of pattern pieces.
Is the replaceable blade option for the PF 60F2 something that can be purchased separately or have to look for a unit with that option? I’m visiting Tokyo next month and hoping to maybe find an unit to bring back home.
Hi David, I believe you can purchase the replaceable blade holder for that model separately. Here’s a link to one website that sells it. https://www.homemaking.jp/products/detail.php?product_id=79219
I don’t have any experience swapping one of these holders out, so I can’t offer much insight, but the model numbers match so I believe it should work for that machine.
Best,
Jon