I am pleased to introduce KATO.

This puzzle is comprised of nineteen blocks with holes, assembled with fifteen dowels, plus four snap-fit fasteners for the claws, and one additional snap-fit fastener to secure the back to the rest of the body.

The assembly requires no screw or glue. It can be disassembled and reassembled as many time you want.

Just like my three first models, KATO is a member of the series of 3D puzzles I've designed using my virtual building set, PUZLO.

KATO files are provided at 100% and 75% scales, and you can also print them at 50% if you wish to create the entire family. But when reducing the scale, the calculated clearances for the dowels to fit into the holes proportionally decrease, requiring an adjustment of the dowels cross-sectional dimensions to preserve the gap.

In the two versions presented, the parts in the files are arranged on two build plates, but you can arrange them differently while maintaining the orientation of the parts as shown to avoid the stair-stepping effect in the curves.

PLATE 1 The first plate contains all the main parts. They are positioned to ensure smooth curves and avoid a stair-step effect. Your 3D printer should handle bridges created at the ceilings of the holes.

PLATE 2 The second plate contains the dowels and the snap-fit fasteners. In the two versions presented, precise clearances have been calculated so that the dowels should slide well into the holes without wobbling. However, these clearances cannot be guaranteed due to variations in filament types, printing speeds, and machine performances. Therefore, it is advisable to run a quick fit test with one single dowel before printing all fifteen required for the final assembly. For this purpose, I included a Test Dowel on Plate 2.

More details are provided in the PNG reference file “KATO_Printing and Scaling” (recommended reading before you start).

You will also find a complete, step-by-step calibration method in EDU LAB 1 (PUZLO), including:

• how to print a few test dowels,
• how to judge the fit (“smooth slide” — no jamming, no wobble),
• and how to fine-tune the dowel size in your slicer without changing the holes.

If your first test dowel is too tight, do not force it—adjust the dowel scaling slightly and test again until you get the fit that feels right on your printer and filament.

Technical Specifications Model dimensions:

• 100%: 54 x 180 x 198 mm
• 75% : 40,5 x 135 x 148,5 mm

Filament The model presented is made with a bioplastic PHA : REGEN color ‘natural’ from BOSK. Estimated filament needed (including dowels and attachments) and with 15% infill.

• 100%: 209 gr
• 75%: 108,6 gr

Printing

• Nozzle size: 0.4
• Layer height: 0.25 mm
• Print speed: slow for the parts on the second plate (dowels and snap-fit fasteners).
• No support needed.
• Build plate: preferably smooth.
• Brims: given a clean, well-prepared build plate, provide brims only for the snap fasteners.
• Infill percentage: 15-20%.

Post-Processing
No post-processing is required. All parts can be printed in the same color for a uniform look, or you can print some parts in different colors to personalize KATO and make it uniquely yours.

Scalable The main parts are scalable, while the dowels require careful adjustment. Always adjust the dimensions of the dowels by printing the Test Dowel first, as mentioned above and further described in the PNG image attached: 'KATO_Printing and Scaling'.

Assembly This puzzle is designed to be fun and thought-provoking without being too difficult. Consult the Assembly Instructions (PDF included) or try assembling KATO without help for a challenge.