View Full Version : Ahren's 8020 Router

03-02-2007, 11:10 AM
Howdy All. I've been a long time lurker and tinkerer on the zone. I even built a ghetto CNC router 2 years ago (without posting any pictures -- sorry) from old robot parts at my last job.

Now it's time to really get going -- there's no excuse not to finish this puppy. Without further adieu, here begins my 8020 CNC router project log. I'll be counting on you guys to keep bugging me so it gets done :).

Solidworks is giving me trouble right now, so I'll post a picture of the model tonight. But who cares about models, really? Here are some pics of the actual router. The first 3 are of the gantry as it stands right now. Lots of plans for reinforcement.

The last two show my control cabinet and motors. The motors and drives are matched Vexta surplus from ebay. 300 oz-in NEMA 34's. They cost me $100 for each set about 4 years ago -- I should have bought all 50 the guy had for sale :). These all were used on my previous router with great success.

Spindle will be M12VC -- I already have it and a mount for it from K2CNC. I'm happy to answer any questions.

03-03-2007, 01:31 AM

Looks good so far. Mine is at the pencil stage at the moment although I have got the Zyxlotec(sp) ready to go kit and the bearing blocks and rails and the ballscrews ordered. When I get this drawing finished I can start building too..

Keep up the good work :)


03-03-2007, 01:40 AM
I got Solidworks to cooperate again this evening. Below is the CAD model for the router. I'm particularly pleased with the repeated bearing, drive screw, and motor elements being used with the extrusion.

I'm still interested in stiffening the base structure to reduce any chance of flexing/racking -- I'm open to suggestions, and am currently considering a) fastening a sheet of MDF to the bottom or b) running steel bars, .5" x 2" across the bottom. What do you guys think?

03-03-2007, 01:53 AM
I would design in some triangulation into the gantry uprights.

dan dimock
03-03-2007, 12:10 PM
I wanted to build one out of the 80-20, I got the metel and slides, but I did not have it set up like yous. I think you have the right idea, I was going to sell mine, but now you have given me new hope. I can not wait untill you get it runing- I just want a 12X16 in machine.
Keep us poster.

03-03-2007, 02:04 PM
Glad I can serve as some inspiration. You should be able to get a pretty stiff machine with those sorts of travels. I'll let you know how mine goes, and will post more pictures as I get things put together -- I know that's what people like to see!

Thanks for the advice -- are you recommending triangles between the uprights and the bearing trucks, or somewhere else? I do have some gussets (not shown in the model right now) that are connecting the uprights to the gantry crossbar -- these are crucial. I also have some holding the whole base frame together -- you can sort of see them in the first picture. My beam deflection calcs don't show anything happening to the uprights under load, but I do think I need to stiffen the overall base, as I do see a little racking if I push hard on one side and pull on another.

03-05-2007, 12:51 AM
I have three Super Vexta drives UDX5128NA and one UDX5114NA and the matching motors that were used on a CNC fabric cutting machine. I'd like to build a machine just like the one you're building out of 8020 and the only reason why I haven't started the project is because I don't know how to control these drives with the PC's parallel port. Can you please share this information if you are using the parallel and which software you planing to use. Any help will be very much appreciated.

03-05-2007, 10:44 AM
Hi Gersol!
I'd be happy to help you out with hooking up to the parallel port. That is what I'm doing, and it's really pretty straightforward. I'm using Mach3 software (artofcnc -- search for it on the zone and you'll get about a bajillion hits. It's super popular and a fantastic value). Then all you really need is a parallel breakout board (one with opto-isolators on it is a good idea, but I didn't do this with my first router). Send me a picture or spec sheet on your drives, and I can help you get things hooked up right.

03-05-2007, 02:06 PM
Hey Ahren how about an MDF base as you thought of and some E/G

03-05-2007, 05:29 PM

here is my 8020 build, maybe some ideas for you. there are other 8020 builds too.



03-05-2007, 09:32 PM
Hi Gersol!
I'd be happy to help you out with hooking up to the parallel port. That is what I'm doing, and it's really pretty straightforward. I'm using Mach3 software (artofcnc -- search for it on the zone and you'll get about a bajillion hits. It's super popular and a fantastic value). Then all you really need is a parallel breakout board (one with opto-isolators on it is a good idea, but I didn't do this with my first router). Send me a picture or spec sheet on your drives, and I can help you get things hooked up right.

Howdy Ahren, thanks for the reply. Here are some pictures I took of the drives. Sorry I don't have the spec sheets for them. I hope they help and thanks again.

03-05-2007, 11:46 PM
Hey Gersol, this looks pretty straightforward. And it's pretty sweet that you have 5 phase steppers -- those should run really smooth and give you good sustained torque.

Send me an email with specific questions -- I'm happy to help, but would prefer not to fill up the project log with this discussion. Get yourself a parallel port breakout board and I'll help you connect things up right. My email is ahrenkj AT yahoo DOT com.

03-06-2007, 10:16 AM
I got some time in the shop last night and attached the gantry bearings (I call this the X axis, since that was the designation used on the gantry robots at my last job). I made the aluminum brackets/standoffs you see bolted to the back face of the gantry to help me get them spaced correctly over the T slot. Hopefully it works out. There's a full length homemade T-nut running the length of the channel under each rail -- 1/8" x 5/8" hot roll from onlinemetals.com.

03-06-2007, 10:26 AM
So I installed the reinforcing brackets in the corners of the gantry -- it feels super solid now. However, if I clamp a stop on one side, and pull with all my strength on the other side, I'm still seeing deflection of ~1/8". See the pictures below. Sorry for the fuzziness -- it was hard to take good pictures while I was horsing on the gantry. At this point, I'm fairly certain it is the structure the rails ride on, rather than the gantry, that is flexing.

I think I really need to focus on stiffening up the structure that the main bearings ride on. 1/2" x 2" steel bar is cheap from onlinemetals ($8 for a 4 foot length), and I live close to them so shipping is usually cheap. I think I'll buy 4 of them and attach them across the underside of the frame of this beasty. That will mean I'm no longer depending on an unsupported 40" span of 1515 extrusion (plus the rail) not to deflect. Let me know if ou guys have other suggestions.

03-06-2007, 11:43 PM
Im not an expert, but I will throw a couple of suggestions at you.
I would use 2 trucks on each rail of your "X axis" (across your gantry)
Also, I think you need to beef up your uprights. alot of torque with that lever you created. you could add a second upright, even some 1515.
Take a look at my build with 8020 and get some ideas.
Have you thought of how to drive the axis' and where to mount lead screws and motors?
good luck. looks good so far.

The actual final detailed build, starts on page 6, thread #62, of my log.


03-07-2007, 01:08 AM
Hey EZ,
Thanks for the suggestions -- I have read through your build log, and your router looks great!
My uprights aren't my biggest problem at the moment -- 8020 deflection calculator shows a 200 lb cantilevered load will cause an end deflection of 0.006" when split between my two 16" risers, if the force load is applied halfway through the gantry crossbar (14.5" height). This isn't great, but it may do for now. Another riseer isn't out of the question -- I may just need to refabricate my bearing truck plates. Alternatively, I could bolt a 6" wide steel or aluminum plate along the riser, Bending deflection is proportional to bh^3, so even with a small b (1/4" thick plate), an h of 6 could stiffen this up a lot.
As for the X trucks, that's a good point. Unfortunately, I'm kinda stuck with what I have, but at least these trucks can hold up to a pretty substantial moment. THK's website shows a max load for these of 194 N*m for a single block in the orientation that will take the greatest moment load. With two of them, (one on top of the gantry, one on the bottom) I'll have a capacity of 388 N*m. At 200 lbs loading, with a 10" lever arm (I don't have my Z coming all the way down -- there will be a table over the center drive screw), I'll have 2000 lb*in, or 230 N*m. Not a lot of safety factor though. Maybe I'll keep an eye out for some rails on ebay with 2 blocks to replace what I have...
The drive system is one thing I'm really excited about for this system -- I'm using the same bearing and motor mount configuration for the entire system. It all mounts up right to the extrusion. I'm having the motor mounts plasma cut, and the bearing blocks are already done. My poor man's angular contact bearing is comprised of a radial bearing inside the block, and a thrust bearing on either side. All of this is sandwiched between a clamping shaft coupler (which couples my screw to some short (4") 1/2" diameter shafts I have) and a shaft collar. This will be clearer once I put it together and take some pictures, but see the CAD model for now. The green items are the coupler and collar, and the red ones are the thrust needle bearings. The orange is a lovejoy coupler that connects the motor to the short 1/2" shaft. The bearing block on the far end only contains a radial bearing. This setup is repeated for all 3 axes on the router.

Thanks a lot for your interest in the project!


03-07-2007, 09:11 AM
Good math, You did way more math than I did.
cant wait to see the drives.

High Seas
03-07-2007, 08:32 PM
I didn't like the flex I was getting in my System1 so reconfigured as System2 - picks show some ideas I found work well with 8020.

:cheers: Jim

Sorry this may be a late entry - "...on the road again...."

03-07-2007, 09:31 PM
Thanks Jim!

My last router was like that -- side driven, but no moving uprights required. This might be a better approach for the high z I have. I would like to keep the screw in the center this time, however, as moving it to the side will further aggravate the small racking problem I'm trying to overcome.

What did you do to make your table super stiff? I think this is all I need to do to get the performance I need.

Alright, it's the end of the day for me, the wife is working tonight, so it's off to the company machine shop now to make some parts!


04-01-2007, 06:53 PM
hey guys i like to know what can i do with this i am a total newbie at this i just got me this from a guy online but i think i need more parts can any one help me out to complete this com and how to set it up anybody with some info please on this

this are the motors
here is one of the parts
and this is the secund one

what ells i need to set this up in my machine thanks

04-01-2007, 07:06 PM
I would post this in a different catagory. maybe under electronics or Stepper Motors and Drives. Probably get a better answer


04-01-2007, 10:07 PM
thansk the reason why i post it here is cus some have the same here they probably will be able to help me

04-01-2007, 11:47 PM
No problem with posting here -- I'm happy to help. These are fairly straightforward to hook up. You have the motors and drives already, so you don't need much else (although a parallel port breakout board is recommended if you care about the PC you are hooked up to). You just need to hook them up to your computer by making the following connections:

1) Connect your parallel port to the "pulse" and "CW/CCW" terminals on the drives. Specifically, for your first axis, hook pin 2 of your parallel port to the "-" terminal on the "CW/CCW" -- this toggles the direction the motor turns. Connect the "-" terminal of the "pulse" to pin 3 of your parallel port. Connect both of the + terminals on your drive to 5V. Repeat for your other 2 axes, going up by 2 pins (4,5 for next axis, 6,7 for next) You may want to get a breakout board for your parallel port to make this easier, and to isolate your parallel port from damage should you accidentally hook it up wrong -- there are several available. Just search for "CNC parallel breakout board".

2) Hook up your drives to 110V on the motor power connector.

3) Hook up the appropriately colored motor wires to the labelled terminals on your drive.

4) Install a demo version of Mach 3 to try it out. Read the tutorials that come with it -- they answer lots of questions.

Good luck. If you have other questions, feel free to PM me, but I'd recommend reading the other threads on the site about stepper motor connections. You have it easier than most, as you already have your drives and power supply in a nice package matched to the motors.

04-02-2007, 12:15 AM
thanks for the answer btw i send you a pm i don't have any info on this no paper worck or anyting this where send to me by a guy who took my money and after 7 months i still have only like 80% of the machine i pay like 3000 for it

is this good


04-02-2007, 07:48 PM
how about this one http://www.probotix.com/breakout_boards

09-22-2007, 08:17 PM
Well, we're finally moved into our new place in North Bend, WA. I have a garage and access to a hefty supply of surplus aluminum extrusion from work, so there's no excuses for me not getting my router up and running. I've made some major progress in the last few weeks, which culminated in hooking everything up today.

Something is not right with the new computer I'm using -- my steppers are acting all wacky. I'll definitely need to lower the gantry down, and may change the design slightly -- it's too flexy for my liking as is. But it should be pretty darn fast once I get my steppers to behave. I'll get all of that figured out soon. For now, here are some pictures of the system, with 3 axes under power and the router mounted.

09-22-2007, 11:40 PM
I never used that lovejoy coupler, when I received it it had far too much backlash.

09-23-2007, 12:17 AM
What coupler did you end up using for your machine? These ones worked ok for me in the past, but I wasn't terribly concerned about a few thou of backlash at that point. Just curious.

I'm still having some issues with my steppers and Mach3 -- not sure what that's all about. Even unloaded, the steppers make a racket, and seem to skip quite a bit. I've tried adjusting the pulse width, and have uninstalled most everything that is not needed on the computer. Maybe I'll try the Mach optimizer to see if that does anything for me. Any suggestions are welcome.

09-23-2007, 12:58 AM
So it turns out Mach3 had a problem with my computer being set to an "ACPI Uniprocessor". I changed it to a "Standard PC" based on advice from Art's XP Optimization manual, and things are working fine now.

Actually, that's not true. Things are working awesome now. I'm not done tuning my motors, but I was able to get 700 IPM on my X. Yes, you read that correctly. 700 IPM -- that's more than 3 times faster than my old machine. The Y is not too shabby right now either at 250 (and it can probably go faster with more tuning), but it has the weight of the gantry to carry. These 5 start ACME's and dumpster's ACME nuts are simply amazing.

I'll post a video tomorrow. I'm stoked. Where is that dancing banana graphic when you need it?

09-23-2007, 07:58 PM
I am doing a simular build right now and I am looking foward to the video of 700ipm. If I can get the same speeds as you I should be able to get across my 31inch table in 2.56 seconds.

09-23-2007, 11:10 PM
The ramping might be slow, though. Those are pretty impressive results Ahren considering you are running ACME & Dumpster nuts. I forget what motors you have installed on that machine?

What I'm using as flex couplers is the shaft to acme couplers from Dumpster's web site.