Which plate allows for a three wheel setup? I can't remember which one would allow it so one wheel will have the eccentric and the other two will be the stationary wheels.
So, will that do 40mm as well as I am interested in the 40mm vslot for strength and against potential sagging across the X beam? The 3 wheel configuration is in a triangle pattern and the wheel that would be at the apex of the triangle is the one that needs to be eccentric. If it will which of those holes is for the eccentric?
Yeah, that one is only for 20mm rail. Beyond that there is only the full size plate. The apex hole is the middle hole of the three larger holes. If you need a 40mm plate however, drilling your own plates is really not that difficult. I just use one of the full size gantry plates as a drill guide.
Thank you, Rick, for this information and do you think you will ever make a slightly larger plate for 40mm as this is too small and the Universal one is way too large (feeling like the 3 bears here, lol)? Lack of a DP (no really good DPs exist anymore that doesn't cost thousands and Craigslist is dead here) or I would do it.
I would second the need for a plate that would ride on 40mm wide V-slot and use 3 or 4 Mini wheels. I am trying to make my current build as OB friendly as possible, but the X carriage is 40mm tall and there doesn't seem to be a viable existing plate out there. I am already getting questions about parts availability for the design, and would like to just say "Go order it all from OpenBuilds"
I have been playing with this in Solidworks and I am stumped. The Delrin wheels have a 3mm spacer but I am finding 4.5mm is needed. The space in the picture (so the wheels actually line up) is 1.5mm from the plate so what has to be done to make sure everything lines up?
If you use 4.5 mm, the sliding section will rub the plate. 5 mm is easily achieved with a 3mm shim and (2) 1 mm washers.
Is the mechanical cad part missing something that the real kit has? I think there is as I am looking at it now and no washers are being used on it at all. Could you confirm if that is a mistake in the cad part or do I have to buy the washers (one under the head and one between the wheel assembly and the 3mm spacer)?
I'm not certain of which cad model you speak or of which kits but doing the math on the regular solid-V wheel assemblies, the assembled wheels are 11 mm thick and when centered on a 20 mm thick extrusion leaves 4.5 mm each side. So if you bolt on a plate using a 4.5mm shim, the plate will also be smack against the extrusion.
This part came from here but which library it came from I forget now. It is the one for download for Solidworks and as you can see that is the wheel assembly up against your V-Slot extrusions. Making the wheel fit the right side extrusion perfectly leaves that gap at the top of the 3mm spacer using the part as it came. So, 5mm (giving .5mm space) spacer (forced to use a 6mm) but the kit comes with none and for the eccentric on that plate what would I need to use? edit: Thank you for your help as I just spotted it and this model was wrong (as I suspected) as nothing comes with the wheel kit. Now that is all cleared up what would I use with the eccentric so everything is lined up correctly?
No, I'm saying if you were to use a 4.5 mm shim your system will bind up. You need at least 5 mm worth of shims to make this work. You could probably get away with a 3/16" (4.76 mm) spacer as it will still create a 0.26 mm gap between the extrusion and the plate. As far as where to get them, try the shop. I'm just a forum mod, I don't sell spacers.
Perfect. With the extra height it also solves another issue I was running into but all fixed now. Thank you again.
Oops, I just realized you edited your question while I was typing earlier. Yes you are pretty much stuck with 6 mm eccentrics going with what is in Openbuilds shop. If you really need to get to 5 mm, Inventables has a low-profile 2 mm eccentric spacer that when combined with a 3 mm spacer will get you to 5 mm but you may find it difficult to adjust.
Well, 6mm spacer is fine but I am a tad stumped about this plate in regards to the eccentric and that is see a big hole for it to go in but I don't see it as a cavity with a bottom as I do on the small plate version so how does it work like that? I would think a large hole for the eccentric to fit in with a bottom that only has a hole the size for the bolt to fit through but on this plate it isn't like that.
I'm going to need to see a lot more of the drawing to answer that. What little you are showing is really not much help.
See that hole in the circle? Why does that hole go all the way through when this hole does not (this one makes more sense to me) The one you showed I don't understand how it could even work effectively from just a giant hole being there.
The larger of the two holes is where the eccentric spacer goes. This allows you to adjust the spacing between the rows of holes to be able to tighten the wheels against the extrusion based on the orientation of the offset center hole in the spacer. The system works the same for the smaller plate. The only difference is that the smaller plate is 1/4" thick rather than the 1/8" thickness of the larger plate and thus has room to provide recesses for the screw heads. You'll note the screw head location in the larger recesses on the right side of the last photo. The variation in location is caused by the eccentric spacer adjusting the location of the bolt center. (Sorry about reversing the orientation of the model from the first row to the last row of the smaller plate example. I didn't realize it until I was posting and don't have time to re-shoot.) I hope this clears things up a bit. Truly the best approach is to get some of these parts in your hands and start working with them, it'll make much more sense. Rick.
Yep, I agree as sometimes you just have to hold it in your hands. Thank you for all of that it makes more sense now.
