Well without caffeine I can’t don’t even notice something as small as a decimal point
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Teeny Tiny Burly is postponing the primo upgrade and standing by, just in case. No pressure.
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I love the numbers…but I still have to do some sort of testing. they way the steel gets handled gives it different properties. And the first time I checked it out I did not like it for a couple reasons.
@dan-htc-touch I am genuinely wanting to know. What OD EMT is available to you locally in your part of Canada? I do not want to exclude anyone, and is the reason we have three sizes to start with. I am trying to hit each region with at least one inexpensive option.
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Hahaha I had originally bought the 1" conduit thinking it was the right stuff, realized it wasn’t so I returned it and then got the 3/4" stuff lol
The good news is I have access to either. I’m going for a smaller build 14"x14" due to space.
The 23.5 is what comes here, but you said this was not coming to primo?
If they use the 3/4” conduit there( 23.5), i’d assume they use the 1” (29.5) also, no?
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I am not sure what size I am going to make. I am trying to build a better machine and make sure you can get the rails still. Wherever you bought your 3/4" from what other sizes do they carry?
Is anyone in Canada and confirm most of you are on the same system us? 1/2" 3/4" 1" EMT If not what sizes of EMT do you have between 25mm and 30mm?
HD has 1/2, 3/4, 1 and 1 1/2 in Ottawa
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I priced out getting 1" DOM instead of 3/4" EMT for a 36x18" Primo:
At Metals Supermarket I would pay $224 to pick it up at a local store, and they want $42 to ship it.
At Metals Depot I would pay $157 / $166 shipped (I’m dubious on that low shipping charge quote).
At Speedy Metals I would pay $97 / $133 shipped.
I can get the EMT for $6.20 for a 10’ length at my local Home Depot, and I’ve spent a whole $24.80 already to get all the conduit I need.
That to say, I’m one of the budget-minded MPCNC builders, so I really hope you do make a 23.5mm version!
1 inch conduit an HD is 10.42 for 10 feet that is what is being talked about now not DOM to make it cheaper and more rigid than 3/4
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I assumed the same modulus of elasticity for all of them, but in reality it will be somewhere between 190 to 210 GPa. I guess EMT material is more on the 190 end. This shifts the numbers about 10%.
Also, I’m not sure about the thickness tolerances of EMT. Minor change in thickness can easily weaken the best EMT to a point that 1"/0.083" tubing wins the competition.
I did the same thing when I first built my Burly. Even AFTER watching the oops video linked on the assembly pages.
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Yup, surprisingly it is a very noticeable difference. Dom is measurably more rigid than SS, I had wrongly assumed SS was DOM that went through another process and made it more rigid (and shiny)…nope.
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0.08 1inch OD mild steel tube had just about as much flex as some 3/4 emt tube I had on hand. It wasn’t Dom, but I was still a bit surprised.
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1” conduit ( 1.163”) has a wall thickness of .057”, which is thicker than 3/4” conduits .049” wall thickness.
1”/.083 DOM might beat the 1” conduit by a small bit in strength, I don’t know-do your math, but by price, the conduit is hands down the true winner, especially if you’re wanting to build a larger machine.
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The only reason I am going to even consider 1" EMT is because people are trying to make a MPCNC out of it in such a huge size. Instead of getting nasty comments about how poorly it functions all over the place I am helping us all out in not forcing you to buy DOM to get a half decent machine at that size. 3’, 3/4" EMT build would not be fun or impressive to use. Would it work, sure will a 1" EMT build cut twice as fast at that size for a few dollars more…probably (to be determined).
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Quick and dirty calc, https://www.engineering.com/calculators/beams.htm
1" 0.083 -.242 deflection
0.065 - …293 deflection
1.163 0.057 - .202 deflection
Theoretically 30+% better but that does not factor in the way the material was handled. As before, cold worked DOM is more rigid. On top of that DOM is more precise in size and shape, and no zinc on the surface. Numbers are good, real tests are best.
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Fine fine fine. If this goes through, I’ll build the teeny tiny with the bigger conduit so we can see it go, then I’ll rebuild the teeny tiny with the 1 inch primo stuff I’ve already got so I can rebuild the 2x4 primo with the bigger conduit parts already tested on the teeny tiny.
Just saying… 
Seriously, though, I hope you know I’m just having some fun here… I’m totally serious, though. But I’m just having fun. Seriously.
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Heck yes, geeking out over numbers is, sadly, fun for me as well.
In the end at this point the assembly is more of a concern than the tubing in normal sized builds. 100% - the only reason to go thicker is to make a larger machine.
For the numbers above that is a 4’ span cut it in half and the deflection is decreased by a factor of 8! 8 times more rigid ant half the length. At that point the deflection plays no part in our use. Then multiply that by two gantry tubes that are slight;y more than simply supported, and you have something along the lines of .01" deflection with a direct 5lb point load. We have under 3lb load spread over about 5 inches, so theoretically the tubes are far under a 0.01" deflection
So you’re saying go straight for the bigger build? Might be a tough sell to the wife, having the big one down with uncertainty on the rebuild, but it’s a risk I’m willing to take. 
Only reason I want to rebuild the teeny tiny anyway is that sweet belt management, which is why I’d put the 1 inch tubes there. I can’t imagine that thing being any more solid than it already is.
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