Different size holes means different size hardware, so more complex BOM. It shouldn’t be too hard to have instructions that show the proper hole to use depending on the build option.
Getting folks to find and follow the instructions is a different problem.
I wonder if the ones that don’t track are the MDF plates. My MDF got all warped and bent after a few months. I had tracking issues and while the logic makes sense that the sides should be in lock and step, that only works if the wheels are pointing perfectly straight. Also over tensioning the x axis can pull the front in slightly which would cause it to not roll straight.
Sure, but I think of it like the ‘gas vs diesel’ fillers.
Diesel nozzles won’t fit in a gas neck.
They will if you try hard enough…
I doubt this. Warps definitely are not limited to MDF, and certainly when the MDF is relatively new it’s dimensions tend to be excellent.
I’ll be using MDF for mine, but I’m also going to prime the MDF before I attach any hardware to it. It tends not to be a problem here, because humidity is generally very low, but ever since having it demonstrated just how permeable MDF is (Put your shop vac on top of a stack of pieces, and you can pick up several layers, because the air flows through them) I’ve never trusted un-primed/painted MDF. I always feel better about it when there’s something sealing it up.
A more complex BOM doesn’t bother me when I’m buying a kit, but it kind of sucks for the guy who has to put the kit together (Ryan. Not inspector #232 at the factory in Shenglong.) and adds its own set of complications and things that can go wrong when building. My last Chinese 3D printer took me a while to assemble just sorting screws.
I agree that dimensions are excellent when it’s not stressed but if you out a bit of load on it it will deform. MDF panels standing on end will bow. My plywood ones, not so much. I had to put an angle bracket on the outside of mine to hold it straight. I will try to post a pic later of how warped they are. I am in Canada and we have high humidity in our igloo shops.
Also the permeability of MDF is awesome. A full CNC with suction table just uses an MDF sheet and draws the air through it. Couldn’t believe it until I actually saw it in person.
I’m in Canada too, but on the prairies, humidity isn’t so much a problem.
MDF has greater forces on it standing on end because of it’s greater mass. The plywood that I have is pretty much all warped to some degree or another, but my MDF is all flat… Well, except for the 1/4" stuff that’s been sitting on a pile of other stuff in the garage for 2 years. That’s warped pretty badly.
Again though, sealing the MDF with primer does wonders for its rigidity and resistance to warping. I built a vacuum chamber, and put some MDF in polyester resin (Fibreglass without the glass fibers) to make a rigid piece for my car audio system, and it withstood holding up the amplifier rack with a 3/4" by 3" piece for 6 years through temperatures ranging from -45°C to +45°C (And heaven only knows what temps inside the car!) I don’t think I’d have tried that with just primer though.
Nice! I like that resin idea!
I keep looking at how cheap linear rails are becoming on amazon, even 2500 mm and longer, and think that might be the solution.
I then think how precise you have to be in setting those rails up, and they are not at all forgiving on mis-alignment, and how they like saw dust less than they like metal shavings.
Which to me spells disaster for a hobby grade machine, and IMHO would require a massive re-engineering of the LR platform to even get installed properly.
I know I have, and I’m sure you as well have seen a ton of machines with the rails mounted sideways on the outside of the frame, meaning the top side of the bearing block are bearing (sorry!) all the weight.
And that still doesn’t keep the flying saw dust away.
I sell a fair amount of used CNC equipment every year, for both metal working and wood.
And if you look at their construction closely, they all have one form of linear rails or ways, as we call them, most of the time enclosed in an expanding bellows, along with wipers, to protect the bearings.
All driven by a 1"- 2" diameter ball screw, hooked up most of the time to a Fanuc AC servo drive motor, run by a Fanuc CNC control, at least on the metal side of things.
All of which is way above a hobby grade machine, and all of which requires manufacturing precision unavailable to your average homeowner with a table saw and a drill press.
I think what you have come up with is fabulous, low cost, accurate machine, (unlike the Maslow - sorry!), and although I have yet to complete my LR, I see the sucess others have had with theirs.
I think if you took a poll of active LR users, you would find the ones with mis-alignment issues to be in the minority (who knows I might end up being one of them!).
Point being, the squeaky wheel (aligned or not) gets the grease, and I think you are hearing more from those who have problems, than hearing the praises of those who don’t.
Just my 2 cents, to stay the course, what you have come up with is to me an engineering miracle, but I must add that I have looked at the success those that put a second set of rails on are having and think that long term, that may be a viable, low cost upgrade.
And not once did I mention the word 23, which to me, being from Chicago, will always refer to Michael Jordan…
I agree, I am one of the guys with full linear rails, the sawdust does not seem to be an issue as even the cheap rail cars have scrapers. I did a some long cuts and it just piled on the sawdust and they had no issues. My issues arrived when the dust started packing on the z bearings. The round rail cars have adjustments to take out any slack. I didn’t see any major improvements in cut quality or speed. I needed them to raise my lowrider and keep the wheels out of the dirt. My wood guide rails on the wheels worked just as good before I needed the extra height