[Halfnutz]

Well I finally feel like Ive got a decent start. I spent the weekend and this afternoon finishing up the Z axis, so now all thats left is the X and Y screws, and a control system. It has been fun, but dont let anyone fool you, this type of machine takes a lot of patience and hard work. I have pics of the whole build to date, I will add them as I have time. Here is how it sits at this point.

Footprint 25x38
Travel 22x32
Z axis has full 8 inches of travel and can be set for full 8 inches of clearance.

Total Cost:

Linear guides THK SR15TB 2 sets X&Y axis ebay 120.00
Linear guides THK HSR15VM & 4 cars Z axis ebay 25.00
2 50 inch rolled ballscrews w/ double preload nuts 200.00
1 12 inch Kirk screw w/ acetal nut Z axis 25.00
3 Centent CNO 162 drives (like gecko, but better) 180.00
45 v 8A, & 12 5A Power supply 35.00
3 nema 23 Slo Syn steppers 50.00
Aluminum 100.00

Total so far $ 750.00

[svenakela]

Hmm... Shouldn't you rotate the z-axis horizontally 180 degrees? As I see it the z-axis should move when you raise the mill, but as I look at the picture the alu plate isn't going to move at all?

[Halfnutz]

Sure it moves, like a charm.

[Splint]

Yes it moves like a charm but the way it is set up at the moment there is overhang with the stationary (base) componant. If you turn it around the other way so that the smaller square section is stationary and the long rectangular section is the moving (up and down) section you will dramatically increase your usable z travel and z clearance.

Splint

[svenakela]

Exactly, by rotating it your z-axis it's not in the way as I tried to illustrate in the picture. It looks like a really nice machine, but it with a minor change it could be even better.

Cheers,
Sven

[Halfnutz]

Yes I could do that if I wanted to but it would be easier to just bolt a plate to the front and move it up all the way. That is why I designed it this way. I have up to 8 full inches of Z and 8 full inches of Z travel. Its designed to be adjustable. When cutting 2D work it is best to have the moment of force the weight as low as possible. If I need extra height I can put a longer plate on the front and move the whole axis up with four screws. But yes, your right, I could easily turn it around and accomplish the same thing.

[JavaDog]

Thanks you for the pictures! You just helped me figure out a problem I was having with my Z-Axis.

Is your gantry all 1/2in aluminum?

[mxtras]

Mr. Nutz -

Very nice looking stuff! I like the simplicity and the craftsmanship.

Excellent work. Are you having a blast, or what? It looks like it!!

Scott

[Halfnutz]

Pretty much, the plate I get are remnants and are all different, but I tried to stay around .5", except the two bearing blocks are 1.25 in. Yes Im having a blast, look at this mess!

[mxtras]

2 things, Mr Nutz -

You are profiling all of those plates on that mill? Nice work!

You said that the aluminum was $100????? Total???? That is awesome - it appears like you have several hundred $$ just in plate - not to mention the extrusion. Good grab! I need to consult with you on raw material purchasing - any pointers?

I like your mess - looks like a really good time...

Scott

[Halfnutz]

Allright, I got the leadscrew for my X axis pretty much done, so all is left is the Y axis and a couple of bearing blocks. I'm hoping to have it done by monday. I am such a burn out. I spent all day (well all afternoon) trying to figure out why my lathe wouldnt cut this screw, and then today I went down and was turning it on when I realized that I had been trying to turn the screw in reverse the whole time. Four hours of scratching my head over that one. Once I turned it on the right way it cut through it like butter. And Scott, I get my plate at Industrial Metal Supply in Santa Anna, CA for 2.00 a lb. Its scrap, but theres nothing wrong with it. The guy at the counter was telling me that K2 gets there aluminum there also.

[DieGuy]

3 Centent CNO 162 drives (like gecko, but better) 180.00

Better, talk to me! Gotta link for these?

[Halfnutz]

Centents come up on ebay occasionally. Thats where I got mine. They were designed by the same guy, Marrisse, that designed the Geckos, from what Ive heard. They are 500.00 new for some crazy reason. I spent two months working ebay to get this set, its not easy, but they are there occasionally. I got my X axis done. It turned out really well. with full travel, no binding, angular contact bearings and an adjustable pre-load that works great. I can move it with two fingers the entire way with no bad spots anywhere. All thats left is the Y axis lead screw ( that one has been driving me nuts, trying to design it cleanly ) and mounting the motors, but I need to get a couple of belts before I mount them, probably middle of next week.

[CNCRob]

Your router looks great, Very professional looking!

[ger21]

3 Centent CNO 162 drives (like gecko, but better) 180.00

I wouldn't necessarily say better. Similar, yes. But I think Geckos are a more refined design. I could be wrong though. But if you can get the Centent's cheaper, it's a good choice.

One problem I see is that you may have some flex with your Z-axis hanging down like that. How much can you get it to flex if you push on the bottom?

[Halfnutz]

The Z axis is set up so that is can be positioned all the way up for tall work, with full 8 inches of travel and clearance, or all the way down, as it is now just to keep it out of the way, for light load high speed engraving. It doesn't flex at all, but I doubt I will use it in this position much. Once I get everything else done I will probably position it around halfway, with four inches of clearance and travel. It only takes four hex heads to move it. I thought about this alot, and came to this design, because if it was set to allways have a full 8 inches of clearance, there would be times when the fulcrum would be too high and cause unneccesary torque on the bearings. And the motor would be sticking up twenty inches off the table all the time. Like I said most of the time it will be in a mid oposition, four inches higher than where it is now. If it turns out that this is too high, I can easily whack 2-3 inches off of the hieght, but I thought this was worth a try.

Yes, I know the geckoes are actually a newer ( and maybe better )version of the centent. Im just trying to rustle some feathers. But they cost three times as much, and there service is lousy, so they must be better!

Allmost done, just need pulleys for my motors and belts so I can mount them and get cutting!

[Halfnutz]

Wow, I tweaked and adjusted the ballscrew preload, and moved the gantries dead end bearing block on it's ballscrew end cause it seemed like it was binding a little. Everything is so smooth now, no grinding or binding, I can push by hand both axis (not Z - its got an acetal nut) from stop to stop, and the ballnut just whizzes effortlessly, even with a decent preload. I'm really happy with the way its gone (so far). Tomorrow I'l get my drive pulleys and belts and I should be dancing a little jig with it by the weekend. Ive got a couple diferent routers to try, but I geusse I'll stick to the Porter Cable to start with. I thought about adding these linear bearings and rods for the Z axis to help suport it when its in the bottom position. These can come off one at a time as the slide goes up. I'm thinking of three mounting positions. One, all the way down with both rods as shown, One three inches higher with just one rod, and all the way up without either rods.

[Halfnutz]

Well, its basically done, Ive got it cutting air hooked up to a HobbyCNC controller while I build the controller for it, and it works fine. I may add another support for the Z axis once I get cutting and see if it flexes any, but it seems really ridgid, so it may be fine the way it is. I still have to make some router mounts also, but right now I'm focusing on the controller. I'm running TurboCNC on an old laptop and plan on upgrading to Mach2 soon also. TurboCNC works OK, I geusse, I just dont like using it. Its like word processing on an XT with PCWrite in 1982. Mach2 looks so nice, I cant wait to get another CPU for the garage, maybe this week I hope. I think Id give up CNC if I had to use a dos system forever!

[Halfnutz]

Wow! This thing is awesome! Even with these little motors and the 2 to 1 gearing on X and Y I can move it along at 200 IPM, but I settled on 120 IPM for X and Y, it seems to run real comfortably there. No binding, no grinding, full travel smooth and true, the motors are noisey but run cool. Man, it is so neet to watch this thing I built from scratch moving around and making all the trippy noises. Ive been running a couple different programs Ive got for engraving stuff, but I need to get busy writing some larger geography for this thing. The total cost ends up right around 1000.00 total, including the controller I have yet to put together, less than a third of what K2 wants for there's this size, and they dont even include controls or motors. I am so glad I built this thing, it has been a blast. If anyone needs help or wants to copy this design I would be glad to help anyway I can.

[santiniuk]

Halfnutz,

Although I missed the progress of this build I have read back through the thread and just want to congratulate you. It looks the business. Really well made.

I'm only a beginner at cnc stuff and I'm learning new methods of assembly from posts like this.

Please continue the thread showing some of the stuff you can cut. A lot of build reports seem to end once they are built but I like to see what type of stuff each machine can do.

Well done