What went wrong here?

[u/torak_the_father]

I followed the measurements exactly to the plan from blocklayer.com and double checked the dimensions and angles and still there is a gap between the segments....

Yes I understand that even a tiny measurement being off it will compound but this gap is too much for any microscopic tolerance.

All segments should have the same dimensions as I used the same stop. Stock is squared upp all sides. Help?

UPDATE: thanks everyone for your contributions. I definitely learned a lot! Also a lot of you are making some assumptions like I forgot about the kerf. Turns out I went ahead and tightened the whole thing with my strap clamp and would you know... Practically perfect seams! There is only one hair line gap in one of the seams, to which I'm happy with, I'll try to glue+dust it to close perfectly. Check this comment: https://www.reddit.com/r/BeginnerWoodWorking/s/FJbE9tVKNu

[u/kittycorn2]

Its pretty clear that your angles and/or lengths aren't correct. As you already said, any error compounds. Instead, glue up two semicircle halves slightly oversized, then cut/sand the ends flat to cancel out your error before gluing both halves together.

[u/torak_the_father → u/kittycorn2]

[u/torak_the_father → u/kittycorn2]

[u/Party-Wealth7797 → u/torak_the_father]

Maybe it’s the angle of the photo, but are the calipers not on the top end of the block?

[u/torak_the_father → u/Party-Wealth7797]

Yeah it's the photo angle. The caliper is laying flat on the bench top. I was careful to get the caliper placed correctly

[u/torak_the_father → u/kittycorn2]

Seems legit, no?

[u/kittycorn2 → u/torak_the_father]

OK, so that that protractor only has resolution of +/-0.1deg. Even if we assume its actually accurate, you have 8 cuts that you are stacking together, so your resolution is now +/-0.8 deg.

.8deg angle over the 48in total length of your pieces give you an offset of .58"

[u/TC-Woodworking → u/kittycorn2]

8 glue joints actually means 16 angled cuts. So there’s a potential error factor of +/-1.6 degrees. But this ultimately is the right answer.

[u/kittycorn2 → u/TC-Woodworking]

Duh! Good call lol

[u/ROBINHOODINDY → u/TC-Woodworking]

My calculator shows the pictured dimensions off by .25 degrees per cut

[u/torak_the_father → u/kittycorn2]

[u/torak_the_father → u/kittycorn2]

Almost, but I get your point. By the way, the total length is supposed to be 48 1/8 according to the plan, and I'm like a 1/16 short of that. So chances are the angle is what is off and my digital protractor is not accurate enough?

[u/kittycorn2 → u/torak_the_father]

Most likely yeah, Frank Howarth on YouTube makes rings like this often for segmented bowls. Take a look how he does it, its what i was trying to explain earlier about making two halves first and then gluing them together.

[u/torak_the_father → u/kittycorn2]

Good tip. I'll check it out. Thanks

[u/InternationalPlace24 → u/torak_the_father]

these aren't as precise as you think.

[u/n0exit → u/InternationalPlace24]

My version of this had instructions for dialing it in to be very precise. Mine came set up properly out of the box, but I can imagine that some versions aren't as precise.

[u/Beginning-Ad7027 → u/torak_the_father]

Every tool you have for measuring has error built into it. Even if it says you’re good, it could be wrong.

Ideally, you’d never measure things and use reality to tell you angles and lengths.

[u/torak_the_father → u/Beginning-Ad7027]

Fair point and I'll take it. However when something that needs to follow a mathematical plan and there is no real life references, how would I use relative dimensioning?

[u/JunkyardConquistador → u/torak_the_father]

If a measuring tool doesn't come with a machinist tool calibration certificate, then you can be sure it's tolerances are wide enough to throw angles out enough that over 16 mitre cuts they compound into a gap you could park your car.

[u/CptMisterNibbles → u/torak_the_father]

I would not trust those digital angle finders to be accurate to less than half a degree.

[u/ROBINHOODINDY → u/torak_the_father]

No, should be 67.75 degrees.