New Machine Build- Critique Time.....80/20 design

[mpre55]

Hello everybody! Another new guy here. First off, thanks to everyone for all of the wonderful information posted. Wow!

Decided it was time for some humble pie, so here is my current 80/20 design. I would value some feedback, as there are many here that have come before me and succeeded.

A little data as well:

cut area: 33" x 28" x 6"

x-axis & z-axis rails are 1530 ( 1 1/2" X 3")

y-axis rails are 1515 ( 1 1/2 x 1 1/2")

most of the joint plates (angles) are standard 80/20

all 80/20 linear bearings on all axis

1/2-10 acme screw w/ delrin nuts (all)

this machine will be for wood and plastic (tolerance of .005" will be fine)

[harry11733]

This looks good. Why did you not use two motors on the x-axis? There would be less backlash associated with the belt drive and more torque to move the heaviest axis.

[mpre55]

I was trying to keep things simple. I didn't want to have to worry about synching motors or using slave cards/protocal. The belt is only $14.00. If I need more power I can simply add a bigger motor. Thanks for the input!

[ger21]

Not sure if I've ever seen anyone who's tried to use those bearings end up happy with them. They tend to bind very easily.

[mpre55]

Thanks Gerry, I'll do some more digging and see what else I can find. Any suggestions?

Matt

[mpre55]

Well after a few redesigns, I'm finally pressing on with getting this thing built. I've managed to get Mach3 installed and running. Tested on my HobbyCNC board and motors and everything seems to be working good there. Definitely gets exciting to see things spinning, even if it is only on my bench! Included a couple of pics and updated drawing of my final design. Let me know what you think.

[mpre55]

Got the main frame pieces bolted up. Final size ended up being 48" x 34". Fabbed up the angles for the trucks, and got them assembled. It feels good to be going forward finally.

[mpre55]

Decided to get a frame built. Should make it easier to work on now that the table can stand on its own.

[Regnar]

Looks nice, You might run into some problems with the Y axis. Being able to line up the lower and upper 80/20 might prove to be alittle more difficult than you imagine. I would suggest placing a single flat piece of steel that expands over both and bolt it togther. Also you might want to loose the middle bearing on trucks. If the center one is off just by a few thousands one of the ends might not touch or the center will not touch. Good Luck and I will be watching

[mpre55]

Good point on the Y-axis. I have some alum plate I could use. I have 1/8 and 1/4, I'll try 1/8th first. Are you thinking of using it as a fixture for mounting the rails, or permanent? Trying to think if the plate needs to be pretty....LOL. Permanent would be fine. I don't have a plate that long of course, a couple of shorter pieces spread out a bit should do the trick, maybe.

Your right on the middle roller as well. I knew that but did it anyway...doh! That's what happens when you start thinking too much..........

Thanks for the input, I appreciate it.

[Regnar]

I would make it permanent. Just because the way you have them mounted it would help with any bowing under heavy cutting.

If the 8020 bearings end up not working for you it should be pretty easy for you to switch over to arhens design. You can purchase them here cncrouterparts.com I made one up on my mill the other day and I have to say they work nice. So nice im starting to rethink a new router table design.

[mpre55]

Thanks for the input, permanent it is. I'm going to try the 80/20 bearings, already bought them, but I do like the look of ahrens slides. Part of my design plan was to be able to switch to trucks, similar to the X-axis, if the 80/20 bearings don't work. Of course, this is my first hack at it, but it doesn't hurt to start thinking about the second one.......