Before I jump in to cad and design my own, has anyone made a lowrider 3 mod to have to Y rails mount to the table flush with the table surface?
Context:
I am building a multipurpose workbench which is a 2700x1500 table. This will serve as a permanent table for a lowrider 3(I’ll upgrade to 4 when it’s ready).
So Lowrider will park at Y max. At the other end of the table I am building in a table saw, router table. Dust collector under the table and possibly a downdraft table.
This will serve as an assembly table and workbench with sectioned spoilboards that can be removed and added as needed - with the first 1000mm under the lowrider staying in place all of the time.
The catch here is, to serve as a table saw I need the Y rail flush with the table. I have a lot of experience designing 3d printers and mods, and have designed(and am currently building) a more rigid steel framed CNC. So I am very comfortable doing the CAD myself - however may as well not reinvent the wheel if I do not have to.
If there is no prior example, this thread will track the progress of the mod and table.
There are a few side mount builds on the non-rail side only, but AFAIK I am the only one that has side mounted both the rail and non-rail sides.
I provided a few details on this thread, but I ran into some technical issues with my SKR Pro controller that I have just finished sorting out, so I haven’t had a chance to fully photograph and document everything yet.
If you want, I can try to send you the 3mf files in a PM, or I might be able to figure a way to share the Fusion files somehow… Not sure if that will work, or if I have to post them in Printables instead. This weekend and the following week is a bit crazy (retirement starts today, birthday is Monday, family is in town for a wedding, lots of running around for personal stuff, etc.), so it might take a few days or longer to get everything together to pass along to you.
Edit - sorry, re-reading your original post, I think I misunderstood your request. I thought you were asking about side-mounting the belt on the Y rail side of the table, but it seems that you are asking about mounting the rail itself flush with the table.
Nobody has done that AFAIK, and it would take some serious redesign of the YZ plate, (the rail would be lower, so you would have to lengthen the plate to have the roller bearings lower while maintaing the Z lead screw aty the original height. I think that you would also have to redesign the belt drive system to compensate for the difference in both the Z plane and the X plane. (I’m not saying this clearly, but if the rail is moved lower, the Y motor housing would be affected. If you move the rail closer to the edge of the table, you will have to figure where and how to mount the belt)
Thanks for the reply. I agree, I can definitely see the sort of redesign required to do it is not insignificant. I can see how it could be done, I just had hoped to avoid taking on yet another design project just now in the case someone has already done this. Guess I had better get on with it!
I’d refrain from doing it. There is a reason that it is designed the way it is. Even the popular superstrut mod is, in terms of engineering, pretty idiotic.
I fully understand lowering the rail increases the size of the moment when cutting forces are applied to the spindle, and one of the reasons the lowrider works with comparatively low powered and simple components is by getting those spindle forces as close to in-line with the Y axis as follows. The z axis design is genius.
I’d agree with you if I were looking at the lowrider in isolation. However I am not. I have limited workspace and a lot of capabilities to build.
Everything in design and engineering is a tradeoff. In this instance I’m choosing the tradeoff of a more stable z axis to gain the ability to run more tools in the same workspace.
If I don’t do this, I cannot use the bench as a table saw. It’s that simple. Understanding the tradeoff and the impact means I can compensate for that in other ways.
I’ll probably need to make the zy plate wider increasing the distance between the front and back rollers to help compensate. If I find it’s unstable I’ll likely replace the Y rail with HGR 20 as there is a comparatively cheap source of it here in Australia.
I wouldn’t describe putting the belts under the table as idiotic without speaking to the individuals about the reasons for their choices. It can be short sighted and needlessly reductive to do so without understanding the whole picture. But I appreciate the feedback, and can see how one might see the want to lower the y rail and think it comes from an uninformed or naive place.
Don’t worry, I know their reason, we had the same arguments for the beta in detail and it makes sense for them as well, but from an engineering standpoint it’s still idiotic.
I am still thinking about a solution to use the table saw with the rail. Maybe make it lowerable so you can hide it when using the tablesaw?
Yeah one option I’d considered is having the y rail hinged and flip out of the way when not in use. The issue there is consistency of alignment of the Y axis in z could very well go out the window. It also means I cannot use the rail for the table saw fence. Not a huge issue as I have a spare set of HGR15 900mm which I can(and still may yet) use for the table saw fence with something like a French cleat and some thumbscrews to attach. But it’s not particularly elegant as far as solutions go.
The other issue is - I want to minimise barriers to use. Ideally the lowrider is 100% ready to go at all times - even if most of the table is covered in my various other projects at least it’s easy enough to clear one end and cut a small part. That’s harder to achieve unless I split the rail. Which I also don’t love for alignment reasons.
My thought would be to put the rail on a lowered platform.
The Y rollers.on YZ Max would be changed to sit on the rail directly under the YZ plate, and the belt holders would have the top parts extended from the lower platform.
This lets you use an otherwise stock LR3 withnthe rail flush or slightly recessed from the surface.
One downside is that the lower platform.for the rail would collect crap. Maybe have lots of openings to let it fall through… The belt holders would also be weaker from being taller.
Honestly I think I’d rather take the reduced performance over the extra complexity. I’m quite comfortable running things that are not stock and taking on the extra work that comes with it. I think I’ll just have to put time in to mitigate the performance impact: fortunately I don’t need this to be an alu cutting beast, I’m building(have almost finished building) a totally different machine for that purpose. I just need this to be good enough to process sheet stock reasonably reliably and accurately.
BTW, bonus points if you can use the LR rail as a fence clamp/guide for the table saw.
For something like thst though, you might need to work with a different rail, something like an SBR16, which I think could do the job. (I was going to try an SBR10, smaller, so not really appropriate for a fence guide, but could probably do the flush top easily enough. Harder to remove the machine from the table though.)
Please forgive Philipp. He uses words like “idiodic” a bit too freely. He’s saying he doesn’t agree and German is his first language, so I give him a pass.
You’re absolutely right that it is a tradeoff and you can do whatever you want with your machine and your table. If Philipp doesn’t like it, he doesn’t have to reply.
The way I would look at it is that you have an imaginary plane where the Low Rider’s spoil board is. Then there us a rail about an inch higher than that (you should look at the part and add the pipe OD (23.5mm for 3/4EMT)). Then the table saw work space is above the height of that rail.
What if you made some runners about 3" by the width of the table. You can insert them into some dog holes or something when you are using the table saw and the table saw face would be flush with the top of the runners. When you use the LR, you could remove the runners (if you didn’t need to cut over the table saw) or put them in (or a spoil board version) to lift the workpiece up over the table saw.
I’ve actually been waiting in hopes than an Aussie ebay store here will get 1700mm hgr20 back in stock. I have some 1000mm ones that I could bit up against them and that gives me a much more rigid rail to work with - making it easier to mitigate the impact of moving the rail and belts lower. Unfortunately for me 1500 and 1200 are back in stock but not 1700.
At these prices they are actually cheaper than sbr and because I’d be using two rails for the full length I’ll have 2 spare carriages per side for the table saw fence. This was the original plan, before I looked at ways to try to lower the lowrider stock rail, but the store being out of stock makes it hard.
$134aud for 2xHGR20 1700mm and 4x carriages is just nuts. It would cost me more to get mgn12.
Another option being buy a set of 1500mm ones and extend my table to 3000 long.
Before I buy anything, CAD. If I can make it work with $22 worth of steel pipe then even better
It may seem crazy to some to spend a couple of hundred on rails for lowrider when it can be built so cheaply in its stock config. I will note that so far the only hardware I have actually had to purchase for lowrider is m5x30 bolts, nylocks and belts. The parts bin has provided everything else. So some money on rails is not a stretch.
Here’s a bit of a warning, something I’m dealing with in my plans…
Captured rails add a very real danger to the machine itself.
The non captured rails that the machine was designed with allow the machine to pop off of the rail if something happens that makes for a significant twist, like one Y motor stalling, or failing when homing the Y axis, say because of a bad homing stop. I’ve had it happen several times with the LR3 and also with the Release Candidate LR4.
When the machine pops off of the rail, I power it down, put it back on teack, inspect the belts and power back up.
I would expect something damaged with a captired rail. The YZ plate would be forced to remain in place while the machine was twisted. Something has to give. Either the machine will destroy a beam brace (most likely from what I’ve observed) or it will bend the rails and destroy a strut (worst case.)
Maybe you get lucky and the motor just skips steps (best case, no damage) or pulls the Y belt holder off of the table.
Chances are pretty good that you end up replacing parts, and it shouldn’t be necessary. I lmow what Im getting into with the captured rail, and my plan with that involved some strain relief (snap-in parts that can also snap out.) Just making it a rigid join means that stress has to go somewhere, so it’s a good idea to know exactly what is going to let go when that strain builds up.
yeah. This is a risk will all CNC. Fortunately at least we are not dealing with 3nm of nema 23 or 12nm of nema34 in this instance damage should not be catastrophic. With a nema 24 printnc, it can be new spindle time if you crash…
Nah, that was deliberately chosen, no need to forgive me. I am pretty well versed in the English language and wanted to make sure that the point comes across. That’s easier if you choose words that aren’t as nice.
But I do swear a lot, even in German.
That’s not what I said.
I still always try to help and was thinking this over, didn’t have a good idea though.
If you have the ability, I strongly suggest trying the machine as designed first. The subtle design choices (like having only one rail) have been debated a lot and the current and LR4 evolutions have years of experience and hundreds of users baked in.
Second to that, making something that uses the current rails, and edits the table is the next best choice. Completely replacing the rails is birthing a new machine, which births new problems only you will experience.
