I agree that this seems like it could be an improvement. I like that it's away from the chips, but it also applies the forces to the gantry in between the linear rails instead of just on the top. That could limit the torque being applied to the ball screw due to the offset loading.

@@gizmobowen I light this idea too and was thinking about how I could pull it off after seeing them working well on the dual Y axis. Some things I'll run into doing it this way are I'll have to redo the cable chain because I won't be able to mount the rests on the back of the gantry without redoing alot of that work and If I mess with the cable chains I might have to recut/redo wiring with is gonna be a huge pain.

This is my own machine and doesn't represent the PrintNC project. Welding always warps but I think the benefits will be worth the added effort to work around that.

@@BryanHoward I just found you, so maybe you've addressed this, but it seems to me welding or brazing the y-axis steel tubes to the cross-platform steel tubes would be helpful regarding rigidity: are you doing that?

@@keithwins TIG brazing silicon bronze is the plan for attaching the risers to the gantry. I've never done tig brazing before so will have to do some practice try's first. I think this would be a good application due to the distortion of welding.

Yeah my machine currently is running servos so having a brake on the Z is an absolute must. Without it, the ball screw can be back spinned when the brake it let go. I’m actually gonna bring in the ball screw closer to the steel beam and flip the ball screw nut housing around. This would have the bolts more accessible than I’ve got in this video. I’ll have less travel in Y and also in X. X doesn’t bother me all that much because it’s the longest axis but Y is already short but it’s the cost of making it more rigid with dual bearings and I think it’d be worth it. I’ve got my printnc cnc machine fully functioning already with the standard 3d printed parts so all these parts would just be made on the machine itself. I’ve cut steel and aluminum and cast iron with good success already. Aluminum is no problem, steel I just make lighter cuts to not push the weak wood and 3d printed parts to breaking point. Alot of the parts to make the gantry risers need to be cut accurately but they don’t necessarily need to be cut on a cnc machine. What I’m thinking of doing is use the cnc machine as a big plotter to mark out accurate cuts and I’ll go back and use the circular saw, grinder, chop saw, etc (conventional tools) to do the actual cutting to save the endmills. I think if I were building a printnc from scratch and plan on doing dual bearing blocks soon after I have it working, I’d do a build with longer rails on the Y axis just because you lose a good deal of travel once you put another bearing block and a respectable amount of space between blocks for rigidity.

I've got a repo of it here. Hasn't been updated with the new changes to the gantry risers though. I'll have to get around to pushing another update out: github.com/bhowiebkr/PrintNC_Pro_Solidworks

yes you could see this article: cncrouterinfo.com/article/avoid-epoxy-granite-for-diy-cnc/

I would also like to know

TIG welding the risers together and than TIG brazing silicon bronze the risers to the gantry tube might be a good way to get around warping. The heat will probably warp it alittle but not as much as straight welding them together.

Not sure but I think hoges is nearly finished with the design of it. It looks like an amazing little cnc and will probably be more popular than the bigger one. Because of its size, it should handle cutting small metal parts much better than the bigger one too.

Thanks, I've put in the link in the description. I do have to make an update as its missing the new gantry risers.

The computer I'm doing cad design on is nothing special. It's something like a 6-year-old gaming PC. 1080 TI GPU. The CNC machine itself runs on linuxCNC.

Thanks for the answer!

These are a lot of interesting ideas. I’ll have to give this all some time to think over. I’ve changed a bit of the design of the risers due to the availability of flat bar steel. I couldn’t get the 3/16 material I was originally going to build the risers out of. Instead I got 1/4" for the same price. Because of the different material thickness 1/8 and 1/4 I’m not going to have a fun time welding and controlling the heat getting pumped into the thinner material. So I’ve changed it a bit to become a bolt on job with around 12 bolts. Because of the thicker material I simplified the risers to not have the inward angle as well. The 1/4" steel is going to be brutally strong anyway to not need such added complexities to be constrained by. In this design the 6 bolts closest to the gantry tube opening get threaded into the gantry risers from inside the tube. The 6 holes further to the inside get threaded past the risers and threaded into the gantry tube. Your suggestions with epoxy granite are compelling that I’ll have to take into consideration. I would like to have the machine functioning with the new risers before filling in the tubes and then at a later date fill them in. Here's a short video of what it has been looking like for the past couple weeks at: kzfaq.info/get/bejne/qrVyrNOXzb--lps.html Would be good to hear your thoughts about this approach. A limitation I already have is. The inside bolts that thread into the gantry. This whole tab+bolts will intersect with the back part of the Z assembly limiting its travel. It’s not a deal breaker but a design nuisance.

@@BryanHoward I can see where the additional bolts on the outside of the riser would be a nascence...Move those bolts to the inside like the rear are located would be a better option...Or flip around where those bolt pattern on the outside of the support would be on the backside...But what ever you do you need to reduce as much welding as possible...adding all the extra material where the Gantry will sit is just undue heat added to the supports... Are you going to stress relieve the supports after you are finished welding up? Might want to address that... You know on the Gantry's out there are no vertical supports on the Gantry...It seems are the gantry's are bolted to the base...Just keep in mind that it is going to be a real challenge to align the vertical holes with the gantry if you have to tweak on the leveling of the Gantry...Then all bets are off...It would seem that the riser piece would have to be match drilled to the gantry 1st then tapped then installed and hitting all would be doable but very challenging... when I get into complicated designs, I often build what I envisioned out of cardboard or wood...get yourself a small sheet of 1/4" plywood from the big box store and cut out on the router...The using wood glue to hold all the corners together like the weld would use tape to hold corners in place while glue is setting up...This will help you get a better understanding of what you are envisioning and fine tune from there...As far as the additional attachment plates are I would NOT use them...If you want to absolutely use hardware on the sides of the Gantry as well as the bottom which I completely understand doing come up with something else to keep the heat down from the welding... With your skills could you design and create on the 3d printer? Then you can add all the design features for attachment of the base and sides in the build...Build the shell of the support just like the flat metal would be...After you get the support made put the gantry in place and pour your Epoxy Granite into the support you just made... This will not have any warpage from heat and be dead nut accurate...FFT With your skills on the CAD drawings sending the support to the printer would be a piece of cake Good Luck I know what ever route you go you will have weight at as many options as possible... You know after mentioning the last option of fabricating out of the 3d printer That appeals to me a whole lot more the welding and then after filling up with epoxy...I would think you would have a heck of a support and be just as ridged as hoped for...Not like steel but plenty strong... Paul