What is the max length and width of the rectangle when mounting the anchor points to concrete?

I see that ‘roughly rectangular shape 8’x12’ ’ is the standard recommendation. I’m wondering how much bigger I can go with the stock belts? Basically, I’m trying to hide the mounting points on teh floor under two sets of shelves that are quite a bit farther apart than 12’

Thanks

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Bigger is better! The bigger you can go the better (generally speaking). You can play around with this tool here to get a sense of what’s possible: Anchor Point Layout Simulator

@bar thank you. Is bigger better for increased precision, or simply because you can use bigger material?

EDIT: looks like each belt is 14.5 feet? JEESH!
𝙰̶𝚕̶𝚜̶𝚘̶,̶ ̶𝚠̶𝚑̶𝚊̶𝚝̶ ̶𝚒̶𝚜̶ ̶𝚝̶𝚑̶𝚎̶ ̶𝙻̶𝙸̶𝙼̶𝙸̶𝚃̶ ̶𝚏̶𝚘̶𝚛̶ ̶𝚑̶𝚘̶𝚠̶ ̶𝚋̶𝚒̶𝚐̶ ̶𝚝̶𝚑̶𝚎̶ ̶𝚜̶𝚝̶𝚘̶𝚌̶𝚔̶ ̶𝚋̶𝚎̶𝚕̶𝚝̶𝚜̶ ̶𝚠̶𝚒̶𝚕̶𝚕̶ ̶𝚜̶𝚞̶𝚙̶𝚙̶𝚘̶𝚛̶𝚝̶?̶

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@bar thanks. Looking at the anchor point simulator, is it safe to say that that 3300x4000 ‘aspect ratio’ is best to maximize the accuracy ‘sweet spot’ (green area) when working typical 4x8 shaped plywood stock?

Another way of asking this question would be: 'is it correct that if i need to make the anchor point spacings bigger than 3300 x 4000 to hide them under the shelves, its best to scale the increase using those same ratios?"

so, for example, to increase by 10% do 3630 x 4400?

E. Miller wrote:

@bar thank you. Is bigger better for increased precision, or simply because you can use bigger material?

bigger material and better angles to pull on.

There is a counter that the more belt you spool out, the more likely it is that
belt stretch could introduce some error. But that’s just engineering thinking,
not backed up by any real-world testing.

David Lang

better angles

makes sense. The closer you get to any one anchor point, the flatter two belt angles get.
Thanks!

E. Miller wrote:

better angles

makes sense. The closer you get to any one anchor point, the flatter two belt angles get.

more the edge between two anchors, the belts get flat compared to that edge and
can’t pull towards it as well.

David Lang

E. Miller wrote:

@bar thanks. Looking at the anchor point simulator, is it safe to say that that 3300x4000 ‘aspect ratio’ is best to maximize the accuracy ‘sweet spot’ (green area) when working typical 4x8 shaped plywood stock?

Another way of asking this question would be: 'is it correct that if i need to make the anchor point spacings bigger than 3300 x 4000 to hide them under the shelves, its best to scale the increase using those same ratios?"

so, for example, to increase by 10% do 3630 x 4400?

Not, that is not a good assumption, we don’t have enough testing to say this,
just ideally have the green area as much larger than your workpiece as practical
for your space.

The nice thing about doing this with concrete anchors is that it’s not that
expensive to put more in and try different sizes, the ones you don’t use can
just have a button head bolt in them to avoid clogging up and be a minimal trip
hazzard.

David Lang

@dlang ok thanks. I’ll just use the simulator with a few dimension options and pick one that looks good.

My theory is the ideal aspect ratio for 4x8 material will always be somewhere between ‘straight out over the corners from the center of of a 4x8’ on the flat/high of the ratio (too ‘flat’), and ‘straight out over the corners from the center of an imaginary square’ on the tall/low side of the ratio (ideal mechanically for the maslow, but ‘too tall’ for rectangular stock)

I predict it should always be somewhere between those two aspect ratios.

Those ratios came because they are the right ratios to hide my anchor points in my garage :grinning:

I kinda had one number that was fixed (3300 for the width of my garage) and I tweaked the other direction to be something that looked good. I think that your theory is probably pretty correct, but also I wouldn’t beat your self up too much trying to get it exactly right. The best solution is whatever fits your space well. The anchor points don’t even need to be a rectangle at all, they can be placed wherever they won’t be in your way.

Thanks @bar . 14.5 ft per belt is a lot to play with. I’m on it.

looks like I’ll also want to print some of Triangle Anchors and get some pins too, right? Otherwise…the anchors will be permanently screwed to the floor. am i on the right track?

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That sounds like the right track to me, although I think I want to redesign that triangle anchor. I think they could be stronger. There are some other designs folks have posted here in the forums which might be better

looking closer at the NOT SHOP, the frogmouth + fancy pins looks good to me. Ok to use those on concrete? QQ: Does the frogmouth stl have a feature that allows the fancy pins to work as expected? Like, a groove or something for the fancy pin ball beearing to lock into?

Asking because if not, I can add it

Mine is 3962.4 x 3962.4. It would not calibrate automatically. I had to manually enter in the corners. It cuts straight. I was actually thinking about making it smaller or at least rectangular instead of square. I also can’t jog at a 45 degree angle for some unknown reason.