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My daughter has these wooden blocks; they're about 5cm on a side. Two faces are machined(?) with various letters, as shown -- and my question is how this face was made?

  • It doesn't look laser-cut, because the lower surface does not look burned or charred;
  • It doesn't look CNC machined, because some of the gaps are impressively narrow and would require a ridiculously small machine bit;
  • It doesn't look "pressed" because that would probably not work on such fine details, but would just squeeze them all flat;
  • But then how was it likely done?

I got them for free 2nd hand, but I know that (for just wooden toy blocks) these were very expensive -- apparently it's some form of name brand, plus the painting is actually very nicely done and the wood itself is a very pleasantly-smelling sort.

Edit: Ooh, my wife explained it to me: They're Tree-D printed!

close-up of wooden block

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  • Oh look, we do have a woodworking exchange. Neat! – KlaymenDK Apr 13 '18 at 19:43
  • CNC + manual finishing off does seem reasonably likely given the precision. But as you say, seems an extremely expensive way to produce something of this level. So without having any firm idea of the whole process what about laser cutting? – Graphus Apr 14 '18 at 9:04
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There are CNC router bits as small as 1/32" (0.79mm) that would perform such tasks as this toy block. For obvious reasons, the feed rates have to be carefully managed.

A skilled operator might create the design for a larger bit to take out the open areas, then perform final passes with the detail bit. If one looks closely at the edge of the cut, it appears there is some roughness consistent with a cutting tool. Due to the tight quarters, it would be near impossible to sand those areas smooth.

I would not reject a combination of methods. CNC routing for the larger areas, detail bits for closer work, followed by hand cutting. I add the latter because of the sharp points in the corner details that would be impossible even with a 1/32" bit.

If the blocks are expensive, that reinforces the aspect of some hand work. It also allows that the entire block could have been done by hand, with appropriate tools of sufficient sharpness. The consistency of the curves contradicts that concept, however.

  • I completely agree that this could have been done solely with CNC routing, obviously using various bits. That just seems insanely expensive in terms of required work time... – KlaymenDK Apr 13 '18 at 19:50
  • A v-bit can give the impression of a sharp corner. With a big industrial CNC, a tool changer would mean that multiple bits isn’t a hassle, especially if they’re making a large number of blocks on the bed at once. – Dan W Sep 2 '18 at 22:32
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Similar work is normally done on a pin router. In the most common arrangement a router table is fitted with a guide arm that aligns a pin with the blade, similar to a turntable. The pin is captured in a template and the work moved around to duplicate the design. A web search should illustrate a plethora of home made and industrial versions.

In a similar vein, there were numerous machines for cutting wood block type which allowed for changing the scale of the template. Hot metal typesetters (used for almost the entirety of the 20th century) have a maximum type size. Display types, such as advertising, often had to be cut into wood instead. Even though that's been supplanted by large format printers there was at one time quite a bit of machinery for mass producing intricate wood carvings.

Best guess is it was cut by a custom made machine provided by an industrial tool maker. Otherwise it was probably a custom carrier/template on a pin router. (Possibly two, one to hog out with a large bit and a smaller second pass for detail.)

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Another possibility is that the work was not done by a router approach, or at least not all of it. A possiblity is that the circle and larger corner walls were done using a router with a largish bit, say the inner diameter of the corner pieces. Then the central letter and the inner corner details were cut from a matching thin sheet using a fret saw and then glued in place.

I'm pretty dubious about getting a router bit to handle the details of the central letter, especially the intersection of the vertical bar and the central horizontal bar. A thin saw blade would have no problem, and would handle the sharp inner corners you see on the letter corner and the corner detail pieces.

Even more radically, all of the internal walls could be cut from a thin sheet and glued in place, with a well cut into the face using a considerably larger router bit. While this would seem to be a lot of work, a positioning jig would make accurate assembly simple, and it would explain the apparently smooth bottom of the well. I'm not sure how you'd get the tool marks out of the wood if you used a small-diameter routing bit, but that may simply reflect my lack of experience in a rather specialized technique.

  • Thanks for the suggestion, but there is no glue involved, and all the grain lines up flawlessly - this is a single piece. – KlaymenDK Jul 14 '18 at 7:07

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