I started a JGRO in May but the 95% humidity and 105 temp (Central Florida)warped it before I got it done. I took it apart a couple of days ago and used the parts to start a new build.

I got a 1/2" thick steel topped 80/20 framed soldering machine from a business that I scrapped out and used for the base of the machine. It is rock solid.

I cut a couple of peices of 3/8" thick 3" x 6" angle aluminum to use as the rail mounts coupled with the JGRO mounting blocks.

The sides of the gantry are 6" Al C channel. The back of the gantry is a pair of 4" C channel. They are bolted together with carriage bolts and slotted so I can adjust the level. There is no need to adjust the pipes on the X since they bolt right to the C Channel and are parrellel.

I have about 6 hours and $50 in it as pictured, mostly in bolts. I have enough scraps of C channel and 80 /20 to finish it. I will use a 1/2" 8 TPI ACME screw that I have on hand to drive it.

I have a little Z axis that I was going to use but it only has 2 inches of travel. It was part of the soldering machine. It has a 3 to 1 reduction pully driving a ball screw and it rides on little v grove bearings and has adjustiable gibs. I will save this unit for a little precision engraver (Another project...)

I am a little weak on the computer end of the build so may consider a "Kit" with 3 steppers, controller software etc... that works together but I am undecided about that yet as I need to keep this low buck.

I am not using any plans as you can tell but plans are over rated:rolleyes:

Suggestions are most welcome.

JIM

I bolted up the lower cross peice today (3" x 3/8" Aluminum plate) that the y drive nut will mount to and added the lower X pipe. I set the rollers on the x pipes and used the calipers to deturmine the distance of the assembly.

I made the Y pipes as wide and long as the table would allow then matched the gantry to this width. Now the X assembly will be built to match it and the Y to match that. This way I get the biggest machine that I can fit on the table and not have to try and draw plans for it.

I got the y rails level and parallel. It slides much smoother than I would ever had thought. The lower cross bar makes it a lot more rigid.

Overall view.

I read the Widget Master posts and decided to up the quality of my build (No where close to his but better than what I was doing). I used the DRO on my mill to drill all the holes in the plates. either of the two pairs of plate that make up the assembly and be flipped, rotated or spun 180 and they still line up perfectly. All locations are with in .001. The plates were squared in the mill. They can stand on my surface plare back to back and are perfectly square. I made the height .002 less than the height of the trucks when sitting on the rails. It was a little to tight since there is no give in the pipe because of the C Channel it is mounted on. I shimmed the cap of the assembly with a single sheet of paper. It is still snug but slides with little effort and no play. It is still preloaded but when I sand the paint off the rails it will be perfect. i can always take out the sheet of paper to ajust it for wear. This assembly would make a great small high precision machine if used as a motion table for a little engraver. it would have about a 8"x 10" motion. I may make another one just like it to make a smaller machine.

The assembly is made from 1/2" thick x 4" wide 6061 aluminum plate.

X On Machine.

Great looking machine. Are you not concerned about flex in your y rail?

jckstrthmghty, Yes I am concerned about Y rail flex. They are the same length as the JGRO rails, just a lot farther apart. I took care of the X flex by uising bigger pipe and the c channel. My carrage weighs about the same as a JGRO. Since the length is the same and the weight the same the Y flex should be about the same. I have a lot of polyester resin on hand and considered filling it with rocks then pouring full of resin. I may just use solid bar if it flexes much when in operation.

I am always open to suggestions that may make it work better. I am finishing the Z design in my head now.

JIM

On my jgro I get significant y rail flex. I've come up with a method of bracing my table but I think supported guide rails might be a better option for you considering your higher level of stiffness in your build materials.

The Z took about four to five hours to complete. i started with a piece of 3" C channel that I cut to fit on the face of the X axis assembly. I milled a little grove down each side so the pipes would lay in it to make sure they are parallel. the holes were drilled in the pipe and the C channel and it was bolted up for fit. Once I decided it was OK I took it apart along with the face of the X axis. I drilled and tapped the X faceplate to match holes I drilled in the Z axis' C channel. I bolted it up and added the pipe.

Next I put the bearing trucks against the pipe and measured it as I did when I set up the X axis (pictured above). Once again I cut the plate .002 smaller to give it some pre load.

After much drilling and tapping I bolted it up with the trucks in place to make sure it would clear everything. When I found the best spot for the trucks I took it apart and drilled and tapped the side plates for the trucks to bolt to.

I put it all back together and it works better than I thought it would.

The preload is so tight (But not to much) that you can't hold a bearing from rolling with your fingers as the assembly is rolled up and down, even with the shafts oiled. if I do manage to burn up a bearing I will replace it with one of the 100 that I got on eBay.

Next is the motor mount for a RotoZip.

The X and Z are so tight and non-flexing that I may rebuild the Y as it appears to be the weakness in the design. I will start with solid rods first and if that does not do it I will make 1/2" thick steel flat plate rails with 12 bearings on each side to support it.

JIM

Here are the first two parts of the router mount. it is made of 1" thick aluminum. The Rotozip as a large mounting area near the head and is around 1.7" dia. I bored the hole on my little Southbend 10K and trued the sides of the peice on my 10" shaper. I was not going to use my mill and just use the lathe and shaper but it takes much to long so in the mill it went (for the slots and back angle cut). The Rotozip fits so tight in the mount that I could probably use it without the screw being tightened if I took it slow. It will bolt to aother 1" block that bolts to the Z axis face plate. It should be strong enough for a rotozip. I would use stronger side plates if it were for a high HP router but these are 1/4" thick cut out of a peice of Al box material that I found at the scrap dealer.

The mount for the router motor is installed. It took way to long to build because the Jacobs chuck on my mill got stuck and I had to hand drill about 1/2 of the holes. It is very rigid and it's strength will exceed that of the router and bit so it will be good to go.

The MDF is the old table from my JGRO to get an idea of the size of this one.

JIM