Nice job Teflon!

Couple of questions:

• What is the extra long upright in the left rear corner for?

• How did you connect the extra 20x80 "legs" to the standard base?

• Not quite clear how you reversed the X axis beam... You just use 2 universal plates and double wheels a la OX? Then bolted the Z axis to the second front plate with t-nuts? Would it not have been prudent to reverse the Z axis while you were at it? Just flip it around and bolt the gantry plate to the front x gantry plate and have the whole c-beam move up and down. I know mine collects all kinds of junk in the bottom and I was thinking of doing this.

Touch wood, I have not blown anything up with aluminum chips yet, despite having an essentially open power supply and stepper drivers sitting on a DIN rail across the top of my uprights. It's only a matter of time, however, and I have been contemplating making a Plexiglas shield to go over the whole thing with mounting holes for all the electronics. I really like your "drawer" idea, however, and may just go with that.

I know what you mean about dinging the wheels by running the axis to the end stops. I broke one of the mini v wheels on the z axis by doing just that. They hit the lock collar on the leadscrew and cracked. I put rubber bumpers on the inside of the c-beams to prevent the wheels from hitting. (see C-Beam Machine feedback | OpenBuilds) My x axis wheels also have a bunch of dings from hitting the corner braces, I put rubber bumpers on those too. Just put a t-nut in the groove, put a 5x10mm rubber grommet over a screw into the t-nut, then another 10x15mm grommet over that. I realized later that all you would have to do is put a stick on rubber "foot" like used on the bottom of computer enclosures on the inside of the c-beam end plate to achieve the same thing.

My machine just uses an OpenBuilds router mount and a Bosch Colt router. I really like it, even though it is a bit noisy. But, it's essentially a 750W spindle which is much more powerful than the standard 300w and 400w spindles. Mine is not variable speed, but there is a speed controlled model of the Bosch, the PR20, I believe.

Anyway, keep up the fair work! 8D

 

It would be better if you install on the x axis linear guideways like this HG Series - Interchangeable Type - Block On Hiwin Corporation . I built a cnc like yours and at the end of the table appearing appear large mechanical wear on drilling and on milling.

 

Pretty great build, but I do agree with you, the Z might be quite heavy.. How do you mount the spindle bracket ? Do you just drill hole at bottom face and tap M5 to put some mini wheel ?

 

With the flipped X and y gantry what is the total usable surface size? I am highly considering pursuing similar mods to you as the exposed lead screws having been causing me all kinds of problems milling lots of wood. Are you having any issues with the back lash nuts loosing tension after a few hours of milling? I am having to keep re tightening them which would be a really pain in your set up! As for as flipping the z axis the open builds team shared these plates with me. I think if you use the 14 wheel plate you should have plenty support for that heavy spindle. I have been planning on using it for some time now but have not got around to milling it. Got lots of other projects on the go at them moment. Im sure if you milled two of these it will work with a flipped x axis as well.

 

I've been considering increasing the size of the C-Beam machine by doing a couple of mods to the design.

1. Make a couple of plates to mount the X-axis C-beam so that it sits inside the side rails rather than overlaps them. This would get me almost another 60mm of X-axis travel. Maybe even more because I could eliminate the corner bracket and get a bit more travel on the axis. See pix below. Note that these were taken from another design, but you get the idea. I would have to move the 20x40 supports to the back of the uprights instead of the front, and of course lengthen the 2 base cross members by an equivalent amount. This would allow me to make a wider Y-axis table.






2. Remove the large universal build plate on the Y-axis and use the small 125mm gantry plate with internal wheels that is standard with the C-Beam. Then, add linear rails just like you did, except the open type bearings with the fully supported rail, and 600mm length instead of 500mm. Not having the huge universal build plate would allow the Y axis to have much more travel. This mod should give an additional almost 100mm travel to the Y axis. I would not be able to flip the c-beam like you did, without redesigning the whole base (horizontal cross members would be in the way). Thinking of perhaps a piece of weighted stiff cloth attached to the Y table, covering the C-beam, and hanging down over the front of the machine to keep out debris. Somebody had the idea of using a window roller shade, that would work too.

 

I whipped up a quick drawing of my concept. I attached a 2D along with the Sketchup file if you want to take a closer look.

Theoretically, you could have over 400mm of X-axis travel, and over 420mm of Y-axis travel with this machine. The Y-Axis travel is limited by the length of the linear bearing supports, my drawing has them at 600 mm but I think you would have to go longer (800mm?) to get the full 420mm+ travel of the c-beam. With the 600's the linear bearings would end up being pretty close together and would offer less support for the table.

You could put a 400mm x 400mm table on this thing with room to spare. And, it would be cheap to build because all you need is a couple of brackets that you can make yourself, and a couple of longer pieces of 20x60mm, along with the 2 linear rails and the c-beam gantry. Found these linear rails on Amazon, less than $100 for the 2 rails and 4 bearings in an M12 shaft. Might have to add one more 20x40 crosspiece in the base to support the center of the linear rails. Otherwise, it utilizes all the rest of the CBM parts as is. It's 71mm wider than the existing C-Beam machine.

There is a bit of an issue with clearance on the Y-axis stepper motor, you would either have to cut a notch in the table to clear the motor, or simply put some taller spacers on the linear bearings and c-beam gantry plate. The larger table would mean you have much less debris getting into the Y-axis c-beam too.

I'm calling this build the C-Beam Machine Too.

 

Teflon4 | OpenBuilds The new Hi Torque stepper at the OpenBuilds store would easily handle any spindle and allow you to mod your Z axis to your hearts content. Mind you, I think the existing one would handle it no problem. I was thinking of doing a 2:1 or 3:1 reduction on a c-beam using toothed belts, that would also give you much more lifting power. I have also seem 5:1 planetary reduction gearboxes for NEMA 23 but they are a but spendy at over $100US.

 

After a bit more work, the design comes together...

Machine has 500mm x 500mm x 6.35mm aluminum table, with 420mm of Y axis travel, and 412mm of X axis travel. 2 - 700mm linear rails with 2 bearings each support the table, and the c-beam has the standard 75mm gantry plate on it, which also supports the center of the table. I didn't show the bolts on the linear bearings.

This is actually a very nice little modification to the C-Beam Machine, I think I will make this mod to my own machine. Cost for the whole thing would be likely a bit over $150US, the rails are $46 for a set of 2 rails and 4 bearings on Ebay, you would also need the c-beam small gantry plate package which is $50, riser plates, and some spacers, brackets and bolts, a couple of pieces of 20 x 40 mm v-slot, another $50. A couple of home made brackets and the table top and you are done.

Oh, and I forgot a couple of longer pieces of 20x60 mm v-slot for the base cross members. They are about 71 mm longer than the originals because the X axis C-beam is mounted differently.

Images show table at full rear position and full forward position. Just add a 1/2" MDF spoiler board and you are making chips!

If anyone wants the Sketchup Model, I can post it here. Not much has changed from the model above, the 20x40's were added, along with brackets and spacers and the table. The table clears the top of the stepper motor by a couple of mm.




Happy Routing!

 

I read someone else's post about the C-beam machine and the position of the Y-Axis c-beam not being optimal. Something about moving it back by 17mm to get more travel on the Y-Axis. Don't recall where I saw it now... That's what happens when you get old

Anyway, I discovered basically the same thing with this build, to get equal swing +/- on the Y axis I had to move the c-beam back about 40mm, I was looking at it last night and in order to get the c-beam gantry plate in the center of the bed I still need to move the c-beam back another 20mm, or about 60mm total compared to the original C-Beam Machine placement. Not a big deal, but I will have to move the front cross-member back another 20 mm or substitute a piece of 20x80 for the 20x60. It would be nice to keep the front edge of the cross-member aligned with the front of the side rails so I can use a 5 hole corner bracket on the front corners.

Might also put some aluminum angle around the perimeter of the table to stiffen it a bit more, as well as tap some holes for hold downs. Or, bolt on some of this stuff, which is used extensively in woodworking, and uses 1/4-20 tee nuts:



This is a worthwhile mod to increase the machining area of the C-Beam Machine by over 75%!

 

Teflon

Nice machine, do you mind share what size is your spindle? nice and quiet. I am deciding between 0.8 and 1.5 kw.

 

Hi Teflon 4
I like your build, but have a question, what gantry plate have you used for the reversed Y axis?
If its custom, could you post the file.
Thanks