Started first CNC today

[TopSpin80]

I have been designing and working on this project for a while... the whole design isn't finished and I just started to build. The plan is to build this one with the xylotex??sp board and steppers. It will be built primarially out of MDF.. it's only project will probably be to cut the next one out of maybe aluminum?? Today I came up with a plan... the z axis will only have about 2-3 inches of travel. So as the axis I am using 2 threaded rods connected with a cog-belt type system. I have an old prining press camera and fram to begin with... it has tons of pulleys and chain-drive stuff...anyways on this one I am building first the x will be aluminum angle with roller skate bearings riding on square tubing... I haven't seen one with square tubing yet... The y is going to be high quality drawer glides set on 2 different planes to minimize slop...... design not quite finished. Well here is a pictuer of the first set of x bearings. I'm on a budget and I have a time limit.... I get one week until I have to quit on the project and go back to school.. If I am mostly finished my wife might let me keep going.

Ernie

[Mr.Chips]

Hello Ernie,
You'r starting like dozens of others, MDF and roller skate bearings. Here are a couple of tips.
The bearings I started with were made from stamped metal and not machined, they didn't even last through the alignment set-up. The way you can tell them apart is to look closely at the outer surface, on the stamped bearings you can see where the sheet metal is formed around the edges. I baught 100 real bearings from EBAY for $12.00 plus shipping.

Just a thought, when cutting wood and MDF with your CNC there will be LOTS of dust, it may get in the drawer glides and cause binding. I had some good drawer slides too, but decided against them. Found some nice used bearings, for the X and Z axis. I'm using the roller scate bearings for the Y axis.

Sounds like you have a lot of hardware to play with.

Good luck and keep the pictures coming.
Hager

[TopSpin80]

do you have pictures of your y axis? I have a feeling my y with rollerskate bearings won't work correctly.

Ernie

[Mr.Chips]

Ernie

My Y axis is very much like this link. It looks like the plan this buider used is from Crankorgan, he has a variety of designs he sells plans for. If you havent seen his site take a look.

Go to posting #1144.
http://www.rcgroups.com/forums/showt...&pagenumber=77



Here is a CNC made out of drawer slides, go to frame #234. This was designed by "Dickeybird". You might contact him to see how he liked this design.

http://www.rcgroups.com/forums/showt...&pagenumber=16

I didn't buy a plan and I have had to make a lot of major changes, such as design change from a movable gantry to a fixed one, as it was too heavy, I want to build rigid and went over board. It would have been simplier if I had purchased plans. The plans from crankorgan are tried and proven, after studying them you might want to make your own customizations if you want.

Good luck and keep us posted
Hager

[TopSpin80]

The plan is to keep this first machine simple. I have built many much more complex things, on a larger scale. Getting this small and keeping tight tollereances is going to be difficult for me. My dad owns a construction company and we usually build things big, most of our tools are not as precission as I need for this project.

Here is the start.

Ernie

[TopSpin80]

ans some of the parts going together.

[TopSpin80]

I decided on drawer glide for the y on this one for simplicity. This thing has too be done by next week or my wife is making me quit.

[TopSpin80]

I started by making these alignment brackets with a hole saw.... the hole saw was old and I got really frusterated. I then decided to spend as little as possible on this project and just use the band saw to cut out these brackets.

Ernie

[TopSpin80]

Here is the end of pictures tonight. I might do some CAD work on the z axis later on... I did all this today in about 6 hours, so I have been busy.

It is getting really close... If I finish the z tomorow then I am going to order the xylotex parts and maybe need some help with some practice g-code

Ernie

[Mr.Chips]

Ernie,
You'r making good headway. Good choice of "T" nuts on your Y axis rails. MDF isn't strong enough to thread by it's self, on my first version I made my adjusters out of a cutting board it threaded OK but now I have changed my design and will try gang drilling the Y axis end pieces, will see how this goes. There isn't a drill size that matches the 3/4" gas pipe so I baught the next size larger Irwin type bit and put in in the drill press and with a right angle grinder bolted to the table ground the bit down, went too far and the hole's too small so have to get another bit tomorrow and try again.
I'm putting as much alum in my machine as I can, don't have much experience in metal work so it's taking much longer.
Good luck and keep posting the photos.
Hager

[pack rat]

It looks good, and progress is fast. You will be making chips in no time. It is good that the hole saw was dull, square hole for square rail. Maybe that someone is watching over your project. Keep it up.

[DJ Morrow]

Instead of T-nuts, you might try threaded inserts. Very cheap and work just fine.

http://www.thomasregister.com/olc/28207009/thr-what.htm

You can buy them at Home Depot or Lowes. Look in the hardware bins.