Originally Posted by
QuinnSjoblom
I'm not the most experienced on here, but my 2c, all your components will massively outperform that c beam frame. It's definitely going to be your limiting factor from lack of of rigidity. It all depends what you plan on doing. If you wanted to work on a wide range of materials, I would say a taig or sherline would far outperform that c beam in terms of rigidity, but obviously a much smaller workspace. I would imagine the the c beam could handle very slow work in aluminum with small tools, but more than that it's just gonna flex too much. Precision is also gonna be limited.
I built my own machine from the ground up for about what you paid, but I had access to basic tools like a table saw, router, drill press. My machine uses some pretty beefy extrusions, mostly 50mm x 100mm, but it gets most of its rigidity from heavy reinforcement with 1/2" thick aluminum gussets that connect everything together, as well as solid aluminum plates on the front and rear of the gantry, and plates under every linear rail. I bought mic6 tooling plate for all the aluminum parts which can he cut on a table saw pretty easily. I rough cut the parts slightly oversize and made mdf templates for bringing the parts to final size with a carbide flush trim in a router. All drilling done in drill press, also using the mdf templates. I probably only held about a 5 or 10 thou tolerance on these parts, but I designed the machine in a way that it didn't rely on accuracy of the parts, only flatness was important which was already taken care of by using mic6. Holes were drilled slightly oversized for fasteners to pass through to allow adjustability of everything. bought a full set of 20mm linear rails and 1605 ballscrews on ebay for 500 bucks. Basically clones of hiwin but they have performed fantastic for hundreds of hours now. Precision is excellent, about 3 tenths backlash at the most. If I'm paying attention to tool runout, I can hold half a thou tolerance on aluminum parts. Since i knew i would be working in mostly aluminum, i went with the Chinese 24k rpm 2.2kw spindle (6k to 24k range). Not great for steel since sfm is too high at 6k, but I still do some occasional milling in steel with small cutters to keep sfm down. In aluminum it it's great, I run at 14k rpm with a 1/4 3 flute using mist coolant and can remove material at a very respectable rate. If speed is less important that working in a wide range of materials, something like the spindle you selected is better, although check out glock cncs new bt30 spindle, many advantages over r8. Eventually I'm gonna switch to that with a dmm servo driving it.
So basically, if you have access to some basic tools, consider building your own frame, as it will massively outperform that c beam. If you want something more ready to go, I would still consider something different like a taig if you want to work in mostly metal.
Also you can make some changes to your component list to sabe a lot of money. Your steppers and drivers are overkill. Get some 300 to 400oz nema 23's, and a gecko g540. Its an all in one unit with 4 stepper drivers and Bob built in, simply a db25 cord between smoothstepper a g540, that's all. G540 is like 280 bucks or so. Also has that extra driver if you do dual drive x on a Gantry machine which i would recommend. I didn't look at your power supply, but 300 bucks is alot, should be no more than 100 for what you need. Oh, and get the Ethernet smoothstepper, not the usb. Ethernet is so much more stable when it comes to pc controlled machines.