Even rotational center of an equilateral triangle?

[rg12]

Thats my problem...

Designing something in tinkercad, that is an equilateral triangle which I need to have the orange ring centered to it in a way that the triangle will have a round object mounted to it and will spin evenly without having the round object go up and down while spinning.

When I use the editor's align tool (shown in the photo as the black dots (align to left/right/center) it centers the X and Y axis in the way that it's shown in the photo.

If I take the triangle and move it 10mm up then it is almost perfectly balanced over the orange ring but I can't do this by eye as this is for a heavy spinning object and needs to be mathematically centered over the orange ring.

The diameter of the orange ring is 55.70mm and the triangle is 90mm*80.61mm

I thought that if I moved the triangle 10mm up and it looked almost centered then maybe it's because 90mm minus 80.61mm equals 9.39mm so I moved it exactly 9.39mm and it wasn't centered, it needs to be about ten point something to be almost perfect by eye.

How can I solve this?

 

[tkhunny]

View attachment 9774

Thats my problem...

Designing something in tinkercad, that is an equilateral triangle which I need to have the orange ring centered to it in a way that the triangle will have a round object mounted to it and will spin evenly without having the round object go up and down while spinning.

When I use the editor's align tool (shown in the photo as the black dots (align to left/right/center) it centers the X and Y axis in the way that it's shown in the photo.

If I take the triangle and move it 10mm up then it is almost perfectly balanced over the orange ring but I can't do this by eye as this is for a heavy spinning object and needs to be mathematically centered over the orange ring.

The diameter of the orange ring is 55.70mm and the triangle is 90mm*80.61mm

I thought that if I moved the triangle 10mm up and it looked almost centered then maybe it's because 90mm minus 80.61mm equals 9.39mm so I moved it exactly 9.39mm and it wasn't centered, it needs to be about ten point something to be almost perfect by eye.

How can I solve this?

If you know the coordinates of the green corners, and
your green pieces are IDENTICAL and
they really do represent the same relative position in their respective corners of an equilateral triangle,
you're almost done.

Construct a perpendicular bisector on the flat edge of each green piece and
observe that these thee lines intersect in a single point. (If they don't, your structure is not properly aligned.)
Use that point to align with the center of the circle.

At least, that's if I understand what you are asking.

 

[Dr.Peterson]

View attachment 9774

Thats my problem...

Designing something in tinkercad, that is an equilateral triangle which I need to have the orange ring centered to it in a way that the triangle will have a round object mounted to it and will spin evenly without having the round object go up and down while spinning.

When I use the editor's align tool (shown in the photo as the black dots (align to left/right/center) it centers the X and Y axis in the way that it's shown in the photo.

If I take the triangle and move it 10mm up then it is almost perfectly balanced over the orange ring but I can't do this by eye as this is for a heavy spinning object and needs to be mathematically centered over the orange ring.

The diameter of the orange ring is 55.70mm and the triangle is 90mm*80.61mm

I thought that if I moved the triangle 10mm up and it looked almost centered then maybe it's because 90mm minus 80.61mm equals 9.39mm so I moved it exactly 9.39mm and it wasn't centered, it needs to be about ten point something to be almost perfect by eye.

How can I solve this?

Another way to find the center (technically, the centroid) of the triangle is that it is exactly 2/3 of the way down from the top vertex (the center of the top hole), to the bottom edge (joining the centers of the bottom holes). That is, the y-coordinate is (a + 2b)/3, if the top vertex is at y=a and the bottom two are at y=b.

Properly speaking, you want the circumcenter of the triangle (equidistant from the vertices), but for an equilateral triangle, that is the same point as the centroid.

If the ring is fixed and you have to move the triangle, move it so that the bottom centers are 1/3 of its height below the center of the ring.

 

[rg12]

Another way to find the center (technically, the centroid) of the triangle is that it is exactly 2/3 of the way down from the top vertex (the center of the top hole), to the bottom edge (joining the centers of the bottom holes). That is, the y-coordinate is (a + 2b)/3, if the top vertex is at y=a and the bottom two are at y=b.

Properly speaking, you want the circumcenter of the triangle (equidistant from the vertices), but for an equilateral triangle, that is the same point as the centroid.

If the ring is fixed and you have to move the triangle, move it so that the bottom centers are 1/3 of its height below the center of the ring.

It doesn't seem to work...
I centered the center of the two bottom holes of the triangle to the center of the ring and then dropped the triangle one third of the height of the triangle (tried the whole triangle height, also one third of the height of only the circles inside the triangle and also one third of the ring diameter).

 

[rg12]

I think that something is wrong with my measurements...
maybe something is off because it's a bit more complex than a simple triangle...
Will run some tests and update.
Thanks alot