Hi I'm from Europe, so parts are not ordered from Openbuilds shop. I assembled my LEAD cnc, and my wheel-plate assemblies are very sloppy even with the eccentric nuts turned all the way to the tightest position. I just wanted to post here and ask if this is expected, or if something is wrong with my parts. they all more or less look like this when fully tightended on all eccentric nuts. (all markings point inwards)
This is one of the down sides of knock off vendors. You might start by contacting the vendor to see if they will make it right. If that proves fruitless you'll need to set about identifying the problem. Are the hole spacings too far apart or is the beam too narrow. If the hole spacings are too far apart, I know where you can get some proper plates. If the beams are too narrow, I know where you can get some proper beams. And while some will suggest replacing the upper fixed spacers with eccentric spacers, it's really not a good idea. The wheels that support the main gravity load should be in fixed holes as eccentrics in this condition can be slowly knocked out of position. But mainly you need to contact your vendor in order to get this process started.
I have a moderately priced calipers, but I have no idea how accurate it is. That said, the c-beams measure 80.01, so those seem to be fine. could you point me to dimensions of the other parts? wheels and plates? Also, is there any way to make the "fit" better without getting new parts? Adding some shims somewhere, or changing some parts?
If your vendor won't help this guy found a solution ; Cannot make one wheel touch C-profile but it wasn't a quick fix. Alex.
I measured the plates and eccentric spacers: Plates seem fine. Hole distance is fine as far as I can measure them. Holes themselves measure between 7.2 and 7.25 for the eccentric spacer holes. Probably fine? I can't seem to find "official" drawings of the parts on the Openbuilds site. Had to rely on google image search, but I didn't find any info on tolerances. Eccentric spacers seem to have most dimensions about right, but not really spot on. the outer diameter that is suposed to go into the 7.2mm hole in the plate is 7.04~7.08 mm I can't reliably measure the eccentricity of the hole, but i get about 0.9mm when I substract the width of the rim on the thinest and thickest side. I have contacted my seller, (not china, from europe, but I don't want to name names just yet, in case they surprise me with superb service.) and also ordered some replacement eccentric spacers from a different source. maybe they are the problem.
Thanks, I came to that conclusion too and ordered replacement parts there. fingers crossed that those will help.
One other check you can make is center-to-center on the wheels. Clamp the calipers around one wheel and reset dial to zero. Then measure to the outside edges of the opposing wheels. This will give you c/c distance. It should be fairly close to 100.00.
Also, you should probably change the title of your videos and use the name of the vendor you purchased them from. Otherwise you may be misleading people as to the quality of genuine parts (if they are not genuine Openbuilds parts).
The videos are unlisted, and linked only in here and sent to the shop I bought from, so I think the context is always there. I received my replacement parts I ordered from Oozenest and the screws and eccentric spacers have a much tighter fit. I replaced the parts with the new ones, and now have a machine that is actually stable in all axis. In the end I had to replace eccentric spacers in all but the second y-gantry plate. The plate themselves seem good enough, and the wheels and c-beams are on spec too. Its just the eccentric spacers (and possibly the 65mm screws that go in them) that were problematic. now to the squaring and traming part.
