[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.:cheers:

[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.......:cheers:

[mpre55]

Well it's been a while since I've posted on this build, so I wanted to give a quick update.

I decided to scrap the 80/20 bearing idea. As Regnar pointed out, it was difficult lining up the the extrusions for the Y axis. After fiddling with them, and trying to get the bearings to slide easily, decided to stop and do some rethinking. I started looking into Joe's design for his Hybrid and decided to incorporate some of those design elements into mine. I've switched the X-axis to v bearing rollers running on angle. I'm going to use my cam rollers on the y-axis running on some pipe. Thought about switching these over as well, but wanted to use stuff that I had already purchased. The z-axis will also be v bearings. I ordered my v bearings from IMService (cadcamcadcam.com) and I am waiting for them to arrive. In the mean time I've built the two side boxes for the y gantry, and the y carriage box. I forgot my camera at the office, so I'll add some pic's later. I've attached a screen dump of my current design.
This has been a great experience so far, even with the changes. I'm starting to think that I might be able to actually get this thing done now! Thanks for the input and ideas!

[solodex2151]

If you weren't so far ahead with your design I would suggest checking out Ahren's CNCRouterParts.com company. The linear bearings are pretty much what you would need without the fuss and hassle. If you consider a new machine or direction, definitely think about the parts. Ahren is a great guy to deal with, a rare find in business these days.

However, the design looks good. Post pics so we can see the progress...

[mpre55]

Change is good, right?

Couple pics to see where I'm at. I've got the sideboxes done and the Y carriage. Got an e-mail from IM Service (cadcamcadcam.com) that my v bearings have shipped as well. In the one picture you can see my old sidewalls and my new materials. The angle iron is for the v-bearings, the pipe is for the Y axis motion, and the flat bar is for the z-axis motion. Also the new stick of 80/20 for the y gantry.

Also, a quick question..... Is it normal to already think about the second machine?:idea:

[rlrhett]

I am curious to hear how running your v-bearing on flat stock works for you. Ahren's (cncrouterparts.com) system is certainly conceptually similar, but using v-bearings allows you to space them as far apart as you need for stability without buying a second set of bearing blocks. They are marginally cheaper, too. On the other hand, I would worry about the v-bearing wobbling, binding or wearing the edge of the angle iron.

Have you used v-bearings like this before? Is there another build on this forum that discusses using v-bearings with flat stock or angle iron?

[mpre55]

I haven't personally used them yet, but I decided to go with the v-bearings after reading through Joe's Hybrid thread. He switched his design from skate bearings and pipe to v-bearings and angle iron. The v-bearings use concentric and eccentric bushings plus they have dual inner bearings. This allows them to be tight and adjustable, no wobble. From all that I've read, there are being used with great success.

Here is a link to Joe's thread:
http://www.cnczone.com/forums/showthread.php?t=38220

Here is the link where I bought mine:
http://www.cadcamcadcam.com

Hope this helps.

[Regnar]

If you sign up for the Mechmate forum they show you how to turn flat stock into a v shape using an angle grinder and acouple of jigs.

Video of one man doing the grinding

[mpre55]

I'll check it out, already registered with them.......

Is it really necessary to grind them? The flat bar I got (hot-rolled) is rounded on the edges. Just curious. Most of the photos in Joe's Hybrid thread are flat, no grind. I realize that it improves contact area, but with the weights and speeds involved, is it that much of an issue? Any thoughts?

[ahren]

Matt,
This looks like an interesting thread -- it'll be good to see how your design turns out. V-rollers are a great alternative if you're fairly confident in your ability to drill accurate holes, and they do give you some flexibility in terms of spacing. My parts are intended for those who want a "bolt-together" system that keeps the connections simple and robust.

What are you using for your drive screws? If you haven't bought them already, I would highly reccommend dumpster's antibacklash nuts and 5 start screws from McMaster -- this is a solid combo that gives you good speed and efficiency.

Best regards,

Ahren
www.cncrouterparts.com