http://www.cnczone.com/gallery/data/500/240Cnc.jpg
I have had a couple of requests to post the specs and details of my router. It has definately been a learning experience and a year long project. Alot of the parts are surplus.

Construction: Birch Plywood, MDF, Steel and Aluminum.
Configuration: X Axis Rolling Gantry.
Overall Size: 22w x 46L x 28h.
Cutting Area: 30" x 14" x 5".
Spindle: Porter Cable Trim Router and Manual Speed Control. 1/4" and 1/8" collets.
Linear Bearings and Ways: X Axis - Skate Bearings and Supported 1" Black Pipe.
Y and Z Axes - Oilite Bronze Bearings and 3/4" Cold Rolled Steel Shafts.
Leadscrews and Nuts: 1/2" - 10 tpi Acme Threaded Rod. Delrin Antibacklash Nuts.
Stepper Motors: Vexta 6v, 1.2a.
Controller: John Kleinbauer Piker 4X. Resistors for Current Regulation.
Power Supply: 24v, 24a Switching Supply. Regulated 5v for Electronics.
Computer: Pentium 150 mhz. Dual Boot, Windows NTand Dos 6.22. Networked in Windows. TurboCnc 3.24c.
Cost: Hard to say as I have a full junkbox. Under $300 out of pocket.
Plans: In my head. No copies available. ;)

I'll write more later and show you some construction pics.

Chris

Thats a nice looking job youve done there. I was wondering if you could post a picture of something it has cut.

How long did it take to make?

I didnt think it was possible to put NT on a pentium 150. Ive learnt something.

Are you pleased with its perfromance?

When I first bought NT4, It was not long after I bought a "top of the line" Pentium 166. I paid $1200 for the processor alone, as it was about the fastest available at that time. I still use NT4 at work on a 750. Its a bit quicker than Win2K, and uses about 50% less memory, if you can deal with it's limitations (no USB).

Here is a pic of the X gantry under construction:
http://www.cnczone.com/gallery/data/500/240cnc1.jpg
The gantry was built out of 3/4" steel L angle. Lapped over on the ends. Bolted w/ 1 bolt in the corners and a plywood insert set in to stiffen it up.
http://www.cnczone.com/gallery/data/500/240X_Bearing.jpg
The X axis bearings were bolted to the angle iron frame with standoffs to bring them to the center of the pipe rails.
http://www.cnczone.com/gallery/data/500/240X_Rail_Support.jpg
Since the base is 46" long 1" pipe would sag too much so I put them on supports and built the base strong enough support it all.
I don't have a pic of the framework under it all but there is alot pieces to the frame and it is all glued and screwed together.

The computer came from my wifes work as they had grown out of it. At some point it was state of the art. They used it for scientific imaging so it had alot of memory for it's time.

Chris

Very nice! I really like your X axis design. How did you attach the pipe to the support rail?
Have you had any issues with keeping the gantry on the X axis? I had thought about doing the same arrangment, but I was concerned because the bearings being on top and on a side didn't capture around the pipe. Could a lever action from the cutting bit and the fixed table translate to a lifting force at the X axis rails?
Very nice Chris!
Bill

You are right. There isn't really anything holding the gantry down other than the leadscrew and gravity. On the other hand the router wasn't meant to mill steel. I haven't noticed any problem on the parts that I have cut.
The pipe rails are bolted thru the base and the support. I used 1/4" bolts but I think a larger size would be better. Since the pipe is soft the threads can strip out.

Chris

Well, if it aint broke don't fix it ;) You really did a nice job on the router!
Bill

cbnc - Chris - thanks for all that! I'll add your data to the spreadsheet I'm organizing (wanna replace the data call in the Tech Section - How-Tos).
All that info is very helpful to anybody trying to figure out what to do next when getting started. Great job too!
cheers - Jim

if the rail on your x axis was solid steel would you still need the support

1 inch steel rails spanning 46 inches would likely have some noticable deflection.


CBCNC,

Thanks for posting the specs on your machine. I'm currently drawing up some plans for my machine in progress. I am most likely going to adopt several aspects of your design. Specifically the X-axis rail design, and the table w/steel supports.

Ahh, the cutting table. When I first planned it I was thinking of MDF spanning the 44 1/2" with 3/4" angle iron on the outside edges. Well after cutting the iron into the MDF and trying it out, it was too bouncy. So I went to the local scrapyard and bought 20' of 1" square, 1/8" wall, tubing. 4 pieces of that and the table with a 22 lb. weight sags about 12 thou. That's good enough for this router and what I'll be cutting.
Oh yeah, since I didn't want screws up into my cutting table I glued the tubing to the MDF with Liquid Nails.:)

Chris

Shortcomings on my design:

You might as well build a steel frame for the cutting table to sit on. I only had 1" to work with and thicker tubing would be better. Like maybe 1 1/2" x 1".

The gantry is only held down by gravity. So linear bearings that held the gantry down would be better.

Use 5/16 or 3/8" bolts to bolt to the Black pipe.

80 oz. motors are just barely strong enough. I find that I can stall an axis fairly easily.

Use shielded cable to wire your motors and switches. I found that my Porter Cable Trimmer put out alot of RFI and caused the steppers to noticably jump when I turned it on.

Have Fun,
Chris

Originally posted by cbcnc
Ahh, the cutting table. When I first planned it I was thinking of MDF spanning the 44 1/2" with 3/4" angle iron on the outside edges. Well after cutting the iron into the MDF and trying it out, it was too bouncy. So I went to the local scrapyard and bought 20' of 1" square, 1/8" wall, tubing. 4 pieces of that and the table with a 22 lb. weight sags about 12 thou. That's good enough for this router and what I'll be cutting.
Oh yeah, since I didn't want screws up into my cutting table I glued the tubing to the MDF with Liquid Nails.:)

Chris

One thing that I haven't seen done yet is providing support for the table via bearings mounted inverted on the gantry. If your gantry is stiff enough your could mount some rollerblade bearings on the top of the gantry losswer crossmember. the bearings would ride along the 1inch square steel tubing. This way if you had a saggy table it would be lifted to the correct height as the gantry slides under it.

Originally posted by cbcnc
Shortcomings on my design:

You might as well build a steel frame for the cutting table to sit on. I only had 1" to work with and thicker tubing would be better. Like maybe 1 1/2" x 1".

The gantry is only held down by gravity. So linear bearings that held the gantry down would be better.

Use 5/16 or 3/8" bolts to bolt to the Black pipe.

80 oz. motors are just barely strong enough. I find that I can stall an axis fairly easily.

Use shielded cable to wire your motors and switches. I found that my Porter Cable Trimmer put out alot of RFI and caused the steppers to noticably jump when I turned it on.

Have Fun,
Chris

good advise, I expect my first machine to have shortcummings as well. I'm not worried about it because I'm mainly doing this for the "because I can factor", and I'll probably only use it to cut the parts for an all aluminum version before I retire, recycle, or sell it.