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Post by oregon on Jan 13, 2020 13:01:20 GMT -5
Sorta new to sphere grinding here, (picked up a couple machines for not much 
Anyway, the local couple folks like to mark cubes in thirds to mark the corner cutoffs, and that seems to be a traditional method. How do you do it?
My beef is that the third position isn't mathmatically correct, results in about a 10% smaller sphere than would be necessary (in the ideal world).
So I printed a triangle to mark things quickly and properly, but wondering what other folks do. Thanks.
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AzRockGeek
has rocks in the head
Member since September 2016
Posts: 704
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Post by AzRockGeek on Jan 13, 2020 14:35:27 GMT -5
I cut the largest possible cube I can, then I search the garage for something circular that will fit the cube and trace it. I then cut the corners off based on the circular scribe line.  |
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NRG
fully equipped rock polisher
Member since February 2018
Posts: 1,688
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Post by NRG on Jan 14, 2020 14:22:58 GMT -5
Yes, not thirds. Do the math and it's like 27% or similar. It's been years since I did the math so don't remember exactly. But use the math. You only need to make one side. This to set the saw. Once the saw is set to removed edges and corners, cut them off! No lines needed
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Post by oregon on Jan 14, 2020 14:33:13 GMT -5
Yes, not thirds. Do the math and it's like 27% or similar. It's been years since I did the math so don't remember exactly. But use the math. You only need to make one side. This to set the saw. Once the saw is set to removed edges and corners, cut them off! No lines needed ah yeah, I guess that's true if you have a 45 tray bolted down right, hadn't thought that far ahead. Yeah, math is done, essentially printed a rafter square with the appropriate markings on the side for the dimensions of the cube. |
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Post by Pat on Jan 15, 2020 2:23:25 GMT -5
When some sphere makers make a cube first, they then cut off the edges. These edges are at 45? 90? Degree angles. I use them for intarsia work to get that slant. Works well.
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