My own take on the spirit of the MPCNC

I have Gaui X3 sitting on a shelf with an iKon in it. I stopped flying when a friend crashed his Goblin and the repairs were over $700. At the time I was looking at buying a gas powered one that was going to be over $1k used. I decided I couldn’t afford to crash at the time.

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Id still fly the gaui, I used to have 2 of them and were super cheap to fix. Imo the Gaui X3 is the ultimate beater heli.

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It’s pretty amazing. I’ve moved farther away from the RC club I was a part of and I don’t really have anywhere to fly something that big safely. I could fly it in the field behind my house, but it’s a cornfield and if I went down, I’d probably never find it.

I have considered some of the newer blade helis, but I’ve been chasing other hobbies recently.

I also raced the 250 quads for a little while. I didn’t have the time to devote to it and very quickly was being out flown by everyone. At this point, my quad is so far behind on technology it wouldn’t be competitive. I did take it up last year. It still flies well.

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Presenting a 40% complete l-upright!

Experiencing some heavy rain - left a little 5v psu which controls the fan for my (currently empty) mushroom tent too close to the window…the PSU got wet and tripped the RCD/GFCI!

Held off printing the parts as the printer nozzle got blocked so I upgraded to an all metal hotend.

I’ve managed to pick up quite a few lengths of 25mm square box tube which might make up the table…

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It’s little reasons like that why I have UPS’s on both of my printers, a small bit of insurance against short outages, brown outs, or an accidentally tripped gfci or breaker.

I do have a small update in the works to address an issue I found when pushing the machine in aluminum. Just changes 4 of the upper bearing bolts on the carriage to 40mm length and one extra part to print. Havent gotten around to properly testing it but static testing shows promise.

Eeek - should I stop printing the brace?

The Carriage Cable Guide Mount is the only part that will get removed/replaced with the update. If you havent printed it yet you dont need to, if you have or are printing it id let it finish since it is a relatively small part.

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I’ve nearly finished my prints - I only have the spindle holder to go.

I did notice the Z rail holders came off the build plate a little warped, there seems to be some flex to it and I’m wondering if the Z rail and ‘core’ will straighten it out when attached.

I also used gyroid infill for quite a few parts, I realised half way that I wouldn’t have enough filament to complete the parts (it was looking like 3.5-4kg!) So I switched to adaptive cubic.

The parts have been ordered, except the water and cooler pump.

I still haven’t decided on the table design, I really want to go for flood coolant, so I would weld a table for the CNC from steel and enclose it with polycarbonate screens.

This makes me think that I could attach the Y linear rails directly to the steel frame, and that way I would eliminate the need for the Y standoffs, and any sag that may be present.

Do you say any issues occuring from that? It doesn’t seem like the l+r gantry go under the Y rail…

Also - have you tried milling mild steel? I have some laser cut parts that need some features milled into them - they’re tiny things, 3mm*3mm and the features are only 90degree slots with a 1.5mm DOC. It would be nice to automate the process as I’m after consistency which I don’t think I can get on my manual mill.

If not, I will be using this machine to make jigs to mill the parts manually.

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Trying mild steel has been on the to-do list as well as actually testing the updated part. With an Altin coated end mill and some air for chip clearing, I don’t see why it couldn’t handle light steel work like that, especially in smaller sizes. I already have a 1/4" Altin end mill just for testing on steel, just need to spare some time from other projects to get to it.

Technically you could just weld the Y rails to the steel frame with a little bit of spacing, just gotta make sure they stay straight and level with each other. Bare minimum I would say 5/8" from the bottom of the tube, as printed spacing is 42.3mm (1.665"), reducing that would mean less stock clearance. When setting mine up I used my machinist level to get the rails situated using shim stock (can actually see some shims under one of the feet in the manual).

For the Z rail holders, if the thickness is the same along it it should pull straight, if it is not consistent it can force stuff to twist and bind or cause a tramming issue with the spindle when bolted to the carriage. if it is just the portion that doesn’t touch the carriage that is affected, you should be good.

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Are there any tram features built into the X carriage or do we take the shim route?

Its a shim thing with the upper and lower tubes for front/back tramming (place the shims between the tube and upright) and can just loosen and shift the rail holders on the carriage for left/right.

Shimming the X tubes makes good sense. However to shim the tail blocks, you would have to remove the tool holder to access the mounting bolts? Sorry, I am only going off the images in the manual so I don’t have any other images to go off…

Can just slide it up and down on the axis to loosen the inner ones. I left them loose and just used the outer ones during adjustment while checking then tightened when I was done. A ball end driver does make it easier. Shouldnt have to ever pull the spindle holder unless you need to replace the holder or bearings.

OK, thanks. This one just made it to the top 3. I built a Primo about 2 years ago, but I messed up and went the EMT route… am looking to make something with better pipes and this one is catching my eye. I see in the manual that the 1 inch pipes are .08 and the 1.25 pipe is .12. Anything adverse to using .12 on both the size pipes? Other than cost that is…

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Only affect would be rigidity, for larger than 25" working area it would be a good idea.

Currently on mine I actually have .063" wall on the Y rails and .12" wall for both X rails to focus on the printed parts themselves for rigidity. Y has not been a problem so far.

I am planning on the “standard” 25 by 25. My bigger concern for the heavier 1 inch pipe is the torsional flex in the gantry. For example, if I grab the collet end of the spindle and pull towards me, then push on the top of the Z rail mount, how much movement is there? I had a small CNC that had crazy flex. The Primo has some, but not as much as el cheapo cnc…

I am still trying to wrap my head around two motors for the X gantry. I am assuming they are wired independently as there are two end stop mounts to be printed… If the switches aren’t perfectly timed, wouldn’t this cause one motor to “oomph” a touch longer than the other?

It doesnt move much, .12 wall does help for pushing it in aluminum. Had to run the spindle nose against the vise jaw until the steppers lost steps (pair of .65nm steppers) to figure out where I was getting chatter from during a particular load direction. Still need to test the update, but it is a simple thing to install and doesnt require reprinting anything.

I use the pair simply for the torque advantage, only 1 end stop is needed for X to home the machine (fw changes are noted to remove the bit for dual end stops on dual steppers, can just run them in series as well).

So I am currently printing the parts, those uprights are not small… I was thinking, we should start a Facebook group for this machine so we can help each other with builds… I don’t know if it would be uncouth to ask Ryan to have a separate section of this website dedicated to it.

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Sounds like a good idea, except, I don’t do Facebook.
I too have printed all parts and just ordered my tubing. Now I have to build the table this will go on.

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Discord is a pretty good starter chat/forum. The only trouble id that FAQs get lost in the history pretty quickly.

Discourse (this forum) is a bit heavier handed. IDK if you can easily get it set up without paying a bunch for it, or hosting it yourself.

You can also make a subreddit, but you might get people who don’t like reddit complaining too.

Github also has a pretty decent setup for small projects. People can post about issues and you can have a wiki. Combined with a subreddit or discord, it covers a lot of bases.