Bed Rail Steel CNC Router

[JackB]

This will be my first posting. A friend and I have designed a CNC machine and have been building it for the last couple of years. The purpose of the machine, other than keeping us off the streets and out of the bars, is to machine wood and balsa parts for Radio Controled model airplanes.

We call it the "Bed Rail Steel" CNC machine because the main tracks use steel angle from old bed rail sets. The main bearings are skate wheel bearings. It is a 3 axis machine x,y and z. The machine is built mostly out of junk, surplus metal and other parts. We are almost complete with the mechanical construction and about to move on to the drive electronics then the computer program to drive it all. The machine is about 68 inches long by about 18 inches wide and the z axis has about 6 inches of travel. The z axis travel is about right for our purpose since we build the aircraft parts in 2 halves for making fiberglass molds.

Neither of us have any experence with CNC machines so most of our ideas are a little different. We searched the internet for ideas and decided to see just how cheap we could build a CNC machine and still accomplish the intended goal. Since the machine is for wood, balsa and foam we are shooting for 1/64 of an inch accuracy or there abouts.

The router motor we have selected is from Harbor Freight and has a long skinny shaft and is somewhat beefy. The router will mount on the cross slide and can be positioned vertical or +- 45 degrees from vertical. We will be using ball end bits for the finish work.

We have looked at a lot of projects on this forum for ideas and it has been most helpful. There is a lot of talent out there.

I will try to post a picture in a couple of weeks. We need to haul the machine out of the shop into the daylight for a good picture but the rainy weather hasn't made that possible as yet.

Jack and Nick
Edmonds, WA.

[Coogrrr]

I see there arent any updates here and I know in another thread you siad 90% done on the mechanical build out not the elctronic. PLEASE can I have some pics of the build thus far?

I am very interested in seeing how you mated the bearings and the rails etc. I think this will solve some issues for other builders here too!

Thanks for trying a new approach and not being afraid of the word "different" !!!!!

Thanks in advance

Coog

[JackB]

Hi Coog,
Attached are as few pictures to hopefully give you an idea.

The base part consists of a 1 and 1/2 inch thick plywood board. We attached bed rail steel angle to each edge, this will be the rails the gantry will ride on using steel skate wheel bearings. The skate wheels are used on the top, bottom and sides of the steel rails held in place by the 2 aluminum side plates. The aluminum side plates are spaced with 1 and 1/2 inch thick walled aluminum tubing. We used 3 aluminum tubes on the bottom of the gantry and 4 on the top of the gantry. We used threaded rod to hold the side plates together this makes a a very strong package. We then attached bed rail steel to the side plates for the up and down travel for the router again using steel skate wheel bearings. To this assembly we attached more bed rail steel for the cross slide for the router. Each of the cross slide rails consist of 2 pieces of bed rail steel angle bolted together to give us that strange looking cross slide. We need the cross slide to travel outside the width of the table when the router was set at a 45 degree angle this allowed full table width coverage. The cross slide itself is a bit different but seem to work quite well and it also uses a number steel skate wheel bearings.

All this use of "bed rail steel" and steel skate wheel bearings was designed to accomplish a linear bearing concept but made out of junk.

The pictures I am posting today are ones as we progressed through the design and build. The machine is farther along then the pictures show but I will try to post some new ones in a day or two. I got to get some help moving the machine outside for a photo session.

Currently we have all 3 axes done with threaded rod drives, motors and pulleys. We are still machining parts for the optical encoders then it's on to the electronics then the software.

We have no clue if this will ever work but it's been a heck of a lot fun so far.

Jack and Nick

[Jason Marsha]

Looking good, post more pics.

Jason

[Coogrrr]

post more!!!

[stratcat50]

Looks like you're off to a good start. Our machine was built for doing guitar necks & fretboards. The project, like yours, was to keep us out of the bars, etc. but on occasion, sent us to the bar ;^). Working well now and we have a vacuum table almost done.

On your long axis, you might need to double up the bedrails for rigidity to keep the router from sinking in the middle. The rest should hold 1/64" fine.

-- Coogrrr, Good math! That's the formula I've needed to explain why things take as long as they do!

Emory

[JackB]

Actually we mounted the side rails on a 1 and 1/2 inch thick plywood board. Once assembled we had a bow upward in the center. Once we got the gantry built and everything assembled the board came out to almost perfectly level. All the mechanical parts are built an assembled just need to do the electrical wiring and software. Nick and I have sort of taken the summer off for other things and will be starting back on the project soon.