![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi7pRjCDETcqAUkwd4_44veA8wZ-mRsEKdw_k16va9HSDiyowyYY06VEuHWN7BTq3H-_CvxDxd5RCW1dQumk6DMCUzpBhmdgCNG5WedpEHr0kvrKcd-bObFouVHIfzKyfKWD9tRn3jAl40S/s320/icosa7.JPG) |
Truncated icosahedron of the type I will be making.
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![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhg_xTO3GvVvGl_rot3ElEhxHPdRumKjUXww-yD2nPFSTknVfXvBiKFDX2BLnyoYdynciPCVKG6q_HqxGTHuFad7K94f80gbDG7iPeVJmkDQP6oaUkCx2tgBvooFwF34A5AKNrew8l6_q8x/s320/a8.JPG) |
This table for designing truncation pieces this was used to design the extra square sides of ....
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![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhuci_D-0FaIvmnlGOZ7LPtxMwDb9OAJfU_iXC5WrR_EPa8i3g872TEHr1xhccab_NJhbdKdwbAHFqEhbGKGmKgQVd1sbqlZ-okCUZhb8_OUNll-nTnuQLQwj5frfiekru6HcTUEJ0eCOzv/s320/icosa6.JPG) |
this octahedron (about 42mm from edge holdes on squares to centres)
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![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgp60Rod4gKnjHngh01rOJA1SB_aQxAREwxVcH8LQTJZWYt_7YpyNohyphenhyphenflzC9GQGZg7OmbHGFugpFVOvFuw1mCsHdWdFegyjvEAPu8LLKtm5AFM2KTLGrCIPPlebgZJH12GzVszOuQSWMtt/s320/icosa5.JPG) |
and the planned icosahedron faces....
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![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgXJw6J2cuCbTB15R0Dg-gw3mhYjxaDllZ65iguSiyLtBQdBwZzd_PSvsEpTvklI6lGHbSXtBV-xuY65o3C8vw-gjG-jPSIioOMp_iQD8X7ACCa_FRSVwPRZsQZ05yNyuaBi736xIKbNw0r/s320/icosa4.JPG) |
with edge holders 57.2mm from centre. |
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEit97ztPg4dFQpOq9wgKLutQKq1Aseti_HvEs3rQnGht0dYe0Hi7WBABZCPkf7gqSi2xGjhCFJRlZ_nUBG5jx2ZgBn1K5aKCij0BPtGv-AKq-lh2fYDVzGVr_Ofq8w_MOgrMWB_BQqYuSiE/s320/icosa3.JPG) |
The round timber pieces were cut using holesaws to cut through.....
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![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgWlB6S1qUAzsv5ruaBPA22mky_xNeQvW-b8LJvwu3_syQd6NIgR6E6YcgjK9qs6rGQHO4r4SfYmqn6nkEUGtLzyDrnTkVwKNBjECPq91Dq1PK64G54ilmdp1F_LXzozGI3wj3OAiwImWu6/s320/icosa2.JPG) |
3mm plywood.....
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![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj7LfivfX0eECpxYTV1z0pLMCdk8Pp3YvnQW2PVLIa1pJZ6ttAU3xXwWOABDOXBR0GIdZij4Gci1Cuyi6nMBcZsmEY4RBlpixpdK0_4OsAKNWU6w1udM3cDJ8Q7ZEBJJgvvwLVYHnk36S7t/s320/icosa1.JPG) |
in this large drill.
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![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj0KTJbALRzmCJS5T3nKpWefKs1P_jw7slYr3S1HyDa0BaqO6SSxDZP8WPFI-gl0hwHJ3PsGGs98xpTfsjC3DYA51fxPA98zZ9cPmm2JM4znWgln3wmQH4Hw6luvEXihPIIxILOc-VeIAiy/s320/A3.JPG) |
Graphical image of truncations of cd polygons.
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Hi, as described in posts here and here and here, I have been experimenting making regular platonic solids using cds as a base, but haven't yet cracked the 20 sided, triangle sided icosahedron. But a bit of work making a truncated, reinforced octahedron made me realise the reinforcing truncation sides could be made quite easily.
The octahedron only needed 6 extra square truncation sides and I made them from bicycle sprockets of varying sizes. There was a bit of effort designing and making 3 different types of matching surrounds for the sprockets. With 12 truncation sides, the icosahedron really needed a uniform truncation side.
Eventually I wandered out to the shed, grabbed my big, (mostly intact!) holesaws and worked out which holesaw would cut the best truncation sides. Then I made a sample side, and designed and printed an edge adapter for it, using the spreadsheet and graphic 57.5mm measurement as one of the dimensions.
So the sides worked out ok, and I was ready to start making more parts. The round part of the truncation side came first, I was all set up to make that with the holesaw already in the drill. (to be continued)
regards
Steve Nurse
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