Thread: 60"x60"x16" Build from stuff I have laying around

**whiteriver** · 01-28-2010, 04:09 AM

Its been a couple years since I have done anything with CNC. I kinda migrated over to Astronomy. I build a small observatory and decided I need a bigger telescope. A much much much bigger telescope. Well those cost allot of bucks. More than I got. So I decided I need a machine to build a bigger telescope. Save money that way. Well that's what I tell the wife anyway.

So this is a story of the build of the router/mirror grinder/mirror polisher.

Working envelope will be 60"x60"x16". It will be a 3 axis machine with a option for a 4th axis rotary table mounted on the table under the gantry. I made one before and it was pretty cool what you could make with a rotary.
This will be made mostly from stuff I had laying around from my past CNC ventures. I have THK HSR20's and NSK LWLF BCS18's slides and matching trucks. Along with a ball screw and some timing belts and pulleys. I did buy a used very nice screw for the Z axis. All the steel and aluminum I have laying around also.
For the electronics I have 5 or so 850 oz/in servos with 500 count quad encoders. Only need 3 or 4. I also have a hand full of gecko 320s laying about somewhere. I have a couple PSC 1500 power supply/ controllers from Foothills Designs here also. I think I will need a Smooth Stepper to interface via USB to the computer but that's down the road. Control will be Mach3 or whatever it is nowdays. Been away for a few years. About the time Art left from Mach I left. The innovation went out the window with that program..

I have a small shop with a small 14x40 lathe and a very old 9x42 bridgeport with a dro. Also have a small dovetail column mill drill from Enco. A few hand tools welders and a 7x12 Jet bandsaw. So no CNC stuff to help the build out. Just handle turners.
Should be fun and take a few months to finish if I don't get sidetracked. I started around Christmas so there is some progress so far.
I will post lots of pictures. Please post you comments or questions. If you see a potential problem with part of the design as it moves forward please speak up. If you are not sure how a part works or what its for, go ahead and ask. That's what the Zone is for.

Donny

**whiteriver** · 01-28-2010, 07:43 AM

Ok here is some pics of the frame and the gantry. Construction is 4"x4" steel tube 3/16" wall thickness. The uprights and the outside horizontal beams are filled with sand to keep vibrations down. They are capped with 1/4" plate.

Donny

**whiteriver** · 01-28-2010, 07:49 AM

Time to get the rails mounted on the Z axis. Its a little different than some. The trucks stay still and the rails move up and down. The main part of the Z is 6"x6"x1/4" AL tube. The spindle will be mounted inside one end and the motor that spins the ball screw in the other end.
I get more travel this way. Plus its what I had laying around.

Donny

**CarveOne** · 01-28-2010, 01:01 PM

Oh goodie! More machine tool porn over here in the woodworking machine forum. That frame looks like it can support a sizeable chunk of optical glass. How large of a lens do you expect to use in the new telescope?

I have one of the RF35 mills also, and got tired of turning the gear head lift crank. I took it off and adapted a 150 in/lb power feed to it. With that and a 135 in/lb power feed on the X axis it has become much less effort to use it.

CarveOne

**EBC** · 01-28-2010, 02:03 PM

Looks great....I like the sand idea...no problem with moisture?

What were your other "cnc" adventures?

Gene Crain
www.plantasymaderas.com

**whiteriver** · 01-28-2010, 05:14 PM

http://www.cnczone.com/gallery/showg...00&ppuser=1498

Above is a link to my Gallery of some of the CNC stuff I used to do when I was on here.

No moister here in Idaho. Nice and dry. So the sand is not a problem. Besides there sealed up tight from the welded end caps.

On my Bridgeport I have a adapter that fits into the chuck of my 18vdc Dewalt drill. I t raises and lowers the knee just fine. Need to make a adapter for the little Enco mill. It does get old turning that crank.

Mirrors will be up to 60" in diameter. There not very heavy. It's a custom design were working on.

Donny

**whiteriver** · 01-28-2010, 05:26 PM

Here are some pictures of the Z axis build. The motor mount and the spindle mount. Allot of drilling and tapping. The one end plate to stiffen the 6"x6" tube has 8 threaded holes around its perimeter and 4 in the face.
The spindle for the cutter portion of this machine is a 3 1/2hp Porter Cable router. It will be held into place via a 1 1/2" thick clamp. Half the clamp will be mounted inside the 6"x6" tube via 4 bolts. There will be two 1/2" diam bolts that run through the tube and bolt on each side. This is for two reasons. Adds stiffness and it gives something for the other side of the clamp to slide on. There will be 3 holes tapped into the 6"x6" tube that bolts will run into and cause pressure onto the moving part of the clamp. This will lock the spindle in place.

Donny

**multiplex** · 01-28-2010, 05:37 PM

Looks like one hell of a build! i like it!

Sounds like you have a nice selection of parts laying around

keep us updated

**mcphill** · 01-28-2010, 05:58 PM

Can you describe how you "level" the welded up frame enough to bolt the rails to it? They need to be within a few thou of level in order not to bind - how do you achieve that over such a long distance? Is it just not an issue since you mounted each slide to a single boxed element? Even then, though, you need both rails to be "perfectly" parallel and planar... I want to do a large build myself, but this aspect has me a bit stumped...

**whiteriver** · 01-28-2010, 06:25 PM

A very precise machinist level and a very good straight edge. And allot of patience. It took all day to get everything to line up with a couple thou. When you weld on it it can move by as much as 5 thou. You have to put the welds in the right spot and let everything cool before proceeding. And I mean up to 1/2 hour to cool. That metal moves allot.
A much simpler and more accurate method would be to bolt it all together. then you can get it all right where you want it. You can always tack it afterward to hold it more permanent and fill in the cracks with epoxy.

One you have it leveled in both directions and leveled with each other you can tighten down one rail permanently. Make sure its straight. Then with your gantry on there move it back and forth and tighten down the other rail as the gantry moves.
I can move the whole gantry with 1 finger. Give it a push and it will slide to the other end of the table.

Donny

**austin.mn** · 01-28-2010, 06:40 PM

Nice work! I like the design and it looks very well built.

Keep us posted.

**whiteriver** · 01-29-2010, 02:52 AM

The Z is installed. The spindle can move up another 2" or down a few inches in the clamp to give more clearance depending on bit size and material.
Still need to broach the drive pulley and install it along with a belt.
There is 16" of clearance between the bottom of the spindle and the top of the table after 2 layers of mdf are installed.

Donny

**mcphill** · 01-29-2010, 02:18 PM

Are you working from plans? Any chance you want to post them?

**whiteriver** · 01-29-2010, 08:41 PM

No plans. I am just building as I go. There is not much to the mechanics of a 3 axis machine. They are all basically the same. Just the type of slides and what you use for motion changes with what you have or buy.
The Y axis will be a belt so it will a bit different from the other two axis.

Donny

**whiteriver** · 02-07-2010, 10:33 PM

Here is a few more pics of how the X axis screw is attached to the Z axis.
More pics to come. I have drawn up the lower half of the machine in Solidworks to figure out how to make the Y move with the belts. So next weekend I can start build that.

Donny

**whiteriver** · 02-09-2010, 09:10 PM

The other end of the X axis.

**whiteriver** · 03-15-2010, 01:18 AM

I managed to build the timing belt reduction and belt drive. All three axis have the motors mounted and they all move under battery power. Now I have to start running wires.

Donny

**Jason Marsha** · 03-17-2010, 01:35 PM

Great job so far Donny.
What is your gear reduction ratio in pic 3?

Jason

**whiteriver** · 03-25-2010, 03:26 AM

What your seeing in pic 3 is a 4:1. The motor goes 5:1 to a 1 1/4" shaft that splits the power to 2 of the 4:1 boxes. Then the belt drive.
Hopefully when I get back next month I can finish running the wires and make this thing do something productive.

Donny

**whiteriver** · 05-19-2010, 11:39 PM

Ive had this together for some time now. The only problem is now the control boards are back at the manufacturer waiting the long wait to be repaired. I did have it running at 500 ipm till the card failed.

Donny