I have added the internal Frame option to the Github. The openscad source should be able to create almost any size internal frame. I created a sample frame for 210mm Build plate & 300mm Build plate since they are probably the most used. I currently only made this to work with 1/2" EMT Horizontal & Vertical, but could adapt it to the other build options if someone want it. I have only printed the test part to make sure the holes & dovetails work for me.

There are a few variables you can change, but mostly you should only need to change the 2 variables:
Build_Plate_OD = 210; //Diameter of Build Plate
Mid_Leg_Qty = 0, 1, 2 or 3

Emmett-Delta/EMT12_Horizontal_EMT12_Vertical/BottomFrame at master · geodave810/Emmett-Delta · GitHub

I also made a couple of minor changes to the vertex parts for this 1/2"EMTH & 1/2"EMTV build:
Emmett-Delta/EMT12_Horizontal_EMT12_Vertical at master · geodave810/Emmett-Delta · GitHub

 

One thing I missed while looking at the assembly of all the parts is the Heat Bed Bracket hits the Dovetail Frame. I should be able to fix that. I need to add that part to the dovetail frame openscad file for future checking.

Here is what the problem looks like. I circled the problem areas in Red.

 

This turned out to be easier to fix than I first thought. This change also shaved a little plastic off the offending parts.

 

I never actually built a final end product of this design as it did not seem that cost savings to me, but if you are only going as large as 300mm build diameter, I think the version using 1/2" EMT for the horizontal & vertical pipes should work.
geodave810/Emmett-Delta

Rather than printing the large vertex parts to test, I would suggest printing 3 of these Heatbed mounts & put two of your 1/2" horizontal EMT's of the length you are using between them. 2 of the heat bed mounts at the ends will represent the vertex parts & 1 in the middle where the heat bed or build plate would mount. It should only take 2 to 3 hours to print those parts.
geodave810/Emmett-Delta
That should give you a very good idea of how sturdy it will be.

Also those brackets use 25mm between the pipes, if you use the Tall bottom vertex parts, which are 42mm between pipes, you will need a different bracket. I could probably draw one of those up if you need it.

Post some photos when you make progress on it.

 

This image is what I had in mind. Add 3 screws to tighten the brackets to the pipes & try to compress the pipes together. That should give you a good idea as to how strong it will be. Cobalt Griffen has already proved that the verticals will work.

 

You made a lot of progress quickly. Those are pretty long prints as I recall.

You should be able to just use the brackets from: geodave810/Emmett-Delta & not have to drill the pipes. You will need 1 or 2 screws for each bracket depending on the style you use & 4 brackets per vertex or 12 total brackets. I sized the bracket holes for M4 or #8 screws. I am not sure of the lengths of the screws you need. I tested just using those brackets & they felt pretty secure to me, but I did not ever test them printing since I did not build a final machine. Before doing all the brackets, you might want to print 4 of them & see how sturdy it feels with 2 pipes on 1 side of 2 vertex parts.

 

Its looking good. You might want to test fit a slider carriage on one of the columns to see if you have any separation of the pipes where the wheels run over. At 30" height you might be ok, but Cobalt had to add some epoxy or some sort of glue to the inside of the 4 pipes to correct that. For my printing, I am using variable layer heights with the Slic3r Prusa Edition & running my Makerfarm 10" Prusa i3v at 150mm/sec using the klipper firmware. Are you familiar with the klipper firmware? Glad you were able to get the pipes in. What kind of plastic are you using? That looked like PETG in your photos.

The effector with the bamboo looks interesting. I will be interested to see how those work. It always interesting to try new ideas.

Is that the spreadsheet calculator you are referring to? Since you are going with 300mm build plate are you using one of the seemeCNC heatbeds? I also did an openscad calculator for this Emmett using a different configuration, but might be able to figure out what it would be for this configurarion. What is the diameter of your hole patterns for mounting your build plate?

 

Here is an image showing the SeeMeCNC 300mm hole diameter heatbed & I get 16.58" for the side lengths when I drew it graphically in Draftsight. See if this looks correct. The spreadsheet showed 16.628" which is only off by 1.2mm for that distance. I will have to look back on what numbers I used with that spreadsheet.

 

Instead of using PETG, you might want to look at esun PLA+. It has a lttle bit of flex, but not as much as PETG. I have not printed with anything else for over a year & it prints better than regular PLA to me. Here is the link from US importer, but I usually buy it from amazon as they usually have 1 or 2 of the colors discounted.
eSUN PLA+ Filament 1.75mm 1kg (2.2lb)

Here is a short video of my machine printing at 150mm/s with Klipper. Since it is not a large part, it does not get the full 150mm/s speed with acceleration/decelerations.

 

Your delta is looking good. Yes, Klipper supports delta kinematics. On a Delta machine is where it really shines as you can use 8bit controllers on it & get the 32bit speed from the raspberry pi that the heart of klipper runs on. I have a Folgertech delta with an 8bit MKS board I want to put it on, but have not gotten around to configuring it yet. From his features document, "Automatic delta calibration support. The calibration tool can perform basic height calibration as well as an enhanced X and Y dimension calibration. The calibration can be done with a Z height probe or via manual probing" Here are his current features:
KevinOConnor/klipper

 

You are coming right along. There is a Klipper facebook group called "Klipper 3d Printer Controller Firmware" that should be helpful to you if you run into any problems setting up Klipper.

 

If you are referring to the dovetail connections which sounds like you are, the default tolerance is .3mm. In the openscad file you can change that from .2mm to .4mm. You should not get 1mm of slack with that tolerance. Here are the dimensions of that joint connection & I downloaded the STL file from there so I would be sure that was what I thought it should be. I attached an image showing the dovetail dimensions & also a STL file with a .2mm clearance. If you need a tighter fit than that, I could add a couple more even tighter tolerances. It should be a tight fit between those parts.

To change that tolerance in the openscad file, it is line 41 in BottomDoveTailFrame_Rev30.scad
DT_Size = 3; //4 = .4mm clearance
//3 = .3mm clearance (Default)
//2 = .2mm clearance

Let me know if that helps or if I missed what you were referring to.

 

I was using either #8 or M4's in the openscad, but looks like STL files were generated for #8's & since they fit for you, that is what I would use.

 

I usually use Locknuts instead of regular nuts. Lockwashers should work with the regular nuts instead of just using locknuts. I can see where you would not want to use locknuts since your bolts extend quite a bit beyond the end of the nut. I personally do not like to glue things like this together in case I want to take it back apart for upgrade or something.

 

I see what you mean. Glue or Loctite might be your best option then. I have never used Loctite though. If you redesign it with nut traps, I probably do not need to tell you this, but do some small test prints with the traps to get the size that fits best for you.

 

I was thinking about your problem this morning & came up with the idea to glue these nuttraps into the bottom vertex parts where the nuts that hold the bottom plate come thru are attached. This keeps you from having to glue or Loctite the nuts. I called it M4_NutTrap, but think I sized it for the #8 nuts & screws, but it is a simple print to test. I am attaching the .scad & STL file & a screen shot to show it. If I did not get the dimensions correct, you can easily adjust them in the openscad file. I ghosted a 1/2" EMT to show the fit.