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Discussion in 'CNC Mills/Routers' started by Shannon Tolliver, Jan 24, 2021.
I found this to be a very fun exercise in building Bessy and will continue to improve her in the future.
Shannon Tolliver published a new build:
Read more about this build...
More pics please
Will do anything particular you want to see sharmstr?
Here you go.
Very sturdy looking machine @Shannon Tolliver and I really like the idea of using the grommets to bring the wires thought the table. I had forgotten about these guys and I can see using them at the front as well where the probe and Interface wires come up. Thanks for the share
Thanks I'm happy how it turned out considering I made all the aluminum plates manually with drill press and my woodworking saws. There is a few things I'd change if doing it again but mostly minor to make things easier to align and assemble.
Shannon Tolliver awesome machine. Curious about the single HGH20 rail and 2 blocks per side of the Y axis. Good and sturdy? I have another cnc build going and was wondering if you thought one rail was fine enough or if done again would you rebuild with 2 rails per side on the Y axis? I was thinking of running 1 per side myself. And are you cutting just wood or non ferrous metals too. Thanks for your input
So far I think one rail with 2 of the bigger blocks per side is solid. I've tried to see if I could get the Z to have flex and I can't notice any with hand force. So far I've only cut 1/2 acrylic and plywood and the machine has done well. With the acrylic it took 4mm deep passes with a 2 flute 1/4 up cut bit at full speed (a bit of an accident) without issues. I do plan to cut aluminum in the future but that will be in a few months once I get used to the machine and finish getting everything organized in my barn. I want to redo my corner plates in 1/2 inch aluminum and the gantry plates so that I can get my router further back on the Y axis.
Great thanks! Right now I have a machine built with mgn12 rails. Wanting to go hgh20's just wondering how deep I should go.
I'm using 15 on x axis. 20 on Y. 12 on x. I think they all work well for the intended purpose. No problem glad I can help.
@Shannon Tolliver what speeds are you using on your X & Y? I have 16mm ball screws and I fill the whip when I go at around 2540mm/sec and higher.
@Corey Corbin I have also only one rail per Y axis side and I have no problems with it. I have made the Y plate a little wider so that the two carriage blocks are a little farther apart and give more stability. That said, it would be better to have two rail per side but than I would have had to make the machine higher and I didn't want to go that route now. Maybe one day I will change it, but not very likely.
@JustinTime I have my max set at 2500mm but I believe its in minutes. However I don't feel like the machine can actually achieve it with 1616 ball screws. The reason I say this is that when I ran a part at 1000mm/min it didn't seem to be much slower that jogging the machine. My Z is 1605 ball screw and moves much faster. Some day I'll do the math or measure because I am curious what my max is.
Yeah, my bad, I meant 2540mm per minute and not per second.
My Z is only 10mm ball screw and can run much faster too since the length of the screw is only 300mm whereas the X and Y have 1400mm and 1500mm respectively, which is why they whip. I'm planning to put some thrust bearing on the X and Y in the future. I bought the bearings already.
What is the pitch of your ball screw? If your using a 16mm diameter 5 mm pitch ball screw over such a long distance I can see having issues with whip because of higher speed. I'm using a 16mm pitch which runs slower and I haven't noticed whip.
I should probably clarify my statement a bit. The 16mm pitch screw requires less revolutions to move the same distance as 5mm, therefore less RPM are required to achieve the given speed.
Hey JustinTime thanks for chiming in on this.
Yeah, I think thems the one I have, the 1605. I want to cut at higher speeds, >2540mm/min. As long as the bit can handle it my stepper are definitely up to it. All I have to do is make the ball screws up to it too.