Hi all, I am building a Lead machine and I am having issues with the nut blocks and lead screws. It is actually a 1510 machine (I know about whip, I am going to make followers for the lead screws once the build is functional). I sourced the 1540mm lead screws from Zyltech and they are not playing nice with the Openbuilds nut blocks. Very tough to hand thread through the nut blocks, I had to use a drill. I also used silicone oil to reduce friction. I managed to get the lead screws installed and I am now at the step in the build video where the machine gets squared up by moving the gantry all the way to the front of the machine. On one side I can move the lead screw by turning the flexible coupling, but it is very tough. And the other side I just cant turn it at all, it is too tight. The lead screws supplied by Openbuilds worked fine with the nut blocks, and I can move those easily by turning the flexible couplings. So now I am not sure what to do. Does anyone have any experience using Zyltech screws with the nut blocks? I am about to order some nut blocks from Makerstore.cc, I assume they are also using Zyltech-style lead screws and maybe their nut blocks will work better. It is clear that the threads on the Zyltech screws have a thicker/wider thread than the Openbuilds screws. I even tried using lead screws from RoverCNC since they are much more expensive and I presumed higher quality, but they are indistinguishable from the Zyltech lead screws. Now I'm waiting to hear back on whether or not they will even let me return those screws. (100 USD each, including shipping). Any other ideas? Or ways anyone else has overcome this?
If you go waaaayy back in the OpenBuilds videos you find one of the initial instructions is to sand down the diameter at the ends of the screws in order to get the bearings to fit over the ends. This is because originally OpenBuilds used the common market screws which were a true 8mm. In an effort to eliminate this OpenBuilds began having its screws custom rolled and are a now a slight bit under 8mm. (This is why you have to use a slightly fudged number in the system setup in the software as the lead is not a true 8mm due to the custom rolling.) And I know where you're coming from on this. On my current build I had a couple of old stock screws I was using and the current nut blocks took issue. Or more correctly, one of two current nut blocks took issue. One worked fine, one didn't. I just ordered new screws to match but clearly you don't have that option. The other choice would have been purchasing a handful of nut blocks hoping one solved the problem but financially this is not a great option. Don't know what makerstore is selling but it is likely the injection molded plastic ones that are commonly available from China. I have a few and I'm not impressed with the quality. May last a while but I haven't used any because they don't look all that promising. My suggestion would be either order a tap or make your own and re-thread the nut blocks you have.
@Rick 2.0 Thanks for the info. I ended up ordering 4 new nut blocks from Makerstore. I'm hoping these will work well, assuming they are selling the more common type of screw and their parts work well with each other. If they don't work out of the box I will go for a tap as the next possible solution. I had been considering this, and thanks for the direct link. I could probably use at least 1 new nut block anyway. I had to really force one screw through with the drill. Enough force to know something ain't right, and I'm going to have to re-do this when I find it not working right later.
