What free CNC frames 
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How about hockey pucks for the wheels, just add a center hole and you are done, they are ~$1 each, compared to the $4 in the ship. Might help with a guiding rail system, flat to flat at a lower distance than rounded wheels.
Cheers!
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I think an âupgradeâ would be switching exclusively to metric fasteners. Sure, you wouldnât be able to pick them up at Walmart, but every town in the US/Canada has a Fastenal, and McMaster-Carr ships everywhere. Even better, a good reason to order directly from @vicious1.
I understand people think that makes it easier, because â90%â of the world uses themâŚbut 99% of my paying customers are in the US. I will do my best to make sure metric works, always have even before you could buy a single thing from me. I am located int the US and buy bulk hardware in the US, Metric is significantly more expensive. So If I make it all metric only, I instantly raise my costs which passes along to the customers that choose to support me.
I made a machine from day 1 that supported metric and imperial fasteners. This gets brought up so often you would think I made it not support metric, it always, always has. I chose #6 machine screws so M3.5 would work, The whole system is based off M8 bolts that fit the bearings perfectly, in the US we use a substandard fitting 5/16".
Number one complaint. M3.5 are non standard, too hard to get. Odd, I can get those in all the same places that carry metric fasteners in the US. Nothing I can do will be perfect, people will always complain on such a giant project.
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I am with you, I just placed an order on Amazon for some metric bolts, I may have bought out the local supply. Definitely easier to get Imperial, but I like eversweet margarine best.
In a perfect world⌠
Cheers!
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Yeah, my point wasnât so much to convert to metric fasteners (though I would support that) but rather that the design would benefit from embracing one system or the other. Currently accommodating both has its downsides.
Metric fasteners cost just as much up here (Fastenal and McMaster are both US companies, and they donât charge us less); yet I built mine with them because as a fraction of the overall cost, the fasteners werenât a huge amount. In fact the real penalty was having to buy 25 or 50 fasteners when I only needed 4.
I assume imperial fasteners are just as available in Europe are metric are here, but similarly at 3 times the cost.
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Thought of you guys when I read this
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Table saw fence attachment for the lowrider?
I think building a vertical lowrider is a challenge, but totally doable. Actually I would have done it already if I had any available wall space left in my shop, I considered it then had to face the ugly truth that it was not reasonable.
The way Iâd do it would be to use the wall itself as the bed, since itâs made of concrete, then just attach a spoil board to it. So basically everything would be solidly bolted to the wall.
I would build it in âportraitâ mode, so the longest side of the board was placed vertically, to minimize the occupied wall space. That also allows for almost unlimited height, the ceiling being the limit, this way you can park the gantry very high so itâ wonât be in the way when you donât use it, freeing some space to put some table or whatnot under it. Then when you need the CNC you just move the table and youâre good to go.
So the X axis would be the vertical one, then Y axis would be left/right and Z towards the user.
The only real challenge in my opinion is to determine how to move the X axis. For that there are lots of available options, either a belt/pulley system with counterweights, a cable system similar to the garage doors, a rack and pinion system (using a large belt) with a beefy stepper and planetary reduction, a very long leadscrew⌠Each have pros and cons.
Right now If if had to chose Iâd go with belt/counterweigt setup, either in a rack and pinion form or just the regular way. Itâs probably the best ratio easy to build/cost/travel speed/accuracy. The threaded rod is easier to build, but it will move slow and is likely to wobble a lot.
The Z axis would need to be an entirely different system as the current one on the lowrider, so that only the tool moves and not the whole gantry. Iâd make the gantry using 3 tubes, in order to better support the weight of the tool, so two tubes would be parallel to the wall and one tube perpendicular.
Really wish I had more space, that thing would have been really useful in my shop to cut panels and I have lots of ideas on how to build it⌠Maybe one day.
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8â is a standard ceiling here. that means 100% vertical in portrait would leave you no room for the tool or router. On top of that setting a zero on the floor on your hands and knees is not ideal. A tilt would probably be best, but I am not convinced this is the right approach. Work holding becomes extremely important at an angle.
I think most people cutting giant pieces out still need a table to assemble them on. So a flat setup is much simpler and can double as a work table. If anything a tilt provides a place to store material. I screwed up and need to rework my shop a bit. One full sheet of plywood is really getting in my way, I have no where to put it so I just keep moving it around until I get a chance to use it. A tilt or table could also double as a panel saw.
Tilt could be worth it, if I was to do anything to the LR right now I would do a minor update to decrease the unique part count. It is such a hassle to package I might need to raise the price a bit as is. After that think about a full rework.
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Or how about just wheels (appliance casters?) that go on the inside of the end pieces to prevent binding and help with consistency, they are a buck or two each for 1 1/4 " here. Again not sure if that is a minor mod vs platform design.
Cheers!
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That is a redesign. A side wheel is only needed if you do not start your machine squarely, or is help to starting squarely. I would rather make dual endstops the norm before adding more hardware. They accomplish the same thing.
The other option is an asymmetric build with one captured side and the other floating.
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Are they binding because the rails are not straight or because the gantry is not square?
Is there âharmâ done if you run your lowrider into hard stops and the steppers chatter a second or two? Does it damage motors or the belts?
I am not opposed to asymmetric. If you leave a mm or two on each side and engage the motors it works fine as it is, if you leave the motors off and go to the start of the workpiece by (slowly) moving it by hand you can push one side more than the other imperceptibly. If you could roll along one side even it would help with runs that are against an edge vs cutting the center out of something. Same reason you would use a guide rail for anything. Thinking of the 8 foot boards I used for my table, the dido like pockets were not precise enough along the entire length, a free mm off, but enough to make a flush join a matter of chisel and sandpaper vs Ikea wannabe. If you want an 7â Grove in some wood precisely 19.5 mm from the edge, I think it can be done, but the 10th pass it may be off. Hope that explains better where the suggestion is coming from, that and I saw some at the store and bought a few to see if they would even fit.
Dual endstops are a bonus, I may do dual Z as it is as that seems the more troublesome. Nice to have brakes for crazy gcode, but if you standardize dual you may as well go triametic (sp?) drivers, imo. Homing doesnât seem to come up in that manner for me.
Cheers!
No. There are a lot of impact forces (like little hammer taps) which could be stressing the parts. But the motor and belts arenât skipping teeth, they are just flipping between magnetic steps.
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I am still not convinced of this. I donât understand why you donât have tracking issues, honestly. Assuming no forces and perfectly straight wheels, they would track forward and backwards in the same line. And if the machine was square, that line would be parallel to the table. But mine donât track in a straight line. They move slightly to one side moving forward or backward. Thatâs why I added the hack tracks to begin with.
I can imagine that when the bit is moving at an angle, the wheels are rolling and they have lateral forces. I would expect them to not track straight at that point. But I donât think that is my issue either, since mine track funky in the air.
I can also imagine the wheels being a little out of square, due to funny printing. But then they would travel in a straight line, but not square to the table. If one was to the left and the other right, then there would be some funny business for sure.
I can also imagine a little slop in the wheel mounts. From the bolt holes or from the bearings on the bolts. That might be causing the wheels to toe in or out ever so slightly when it changes direction.
W.r.t. wheels on the inside of the gantry, running on the sides. I donât like that idea because I have very little confidence most people can build an 8â table that is the same width across the whole thing.
I assume the asymmetry youâre talking about is trying to make it use only one wheel, and keep pressure always on that side. Not sure how that would work.
I like the tracks, personally. I think they are easy to install nearly perfectly straight if you have a nail gun or enough clamps. Using the gantry itself as a guide.
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I had to install tracks on mine as well. But I know I have a geometry issue as one of the sides tilts outward (positive camber, I think).
I also would like to see new Y-plates that are stiffer and with more area to support installation of a power strip, and RPI, and the controller. I was cutting this weekend and the power cord to the RPI got pulled out. Added a good 15 minutes or recovery time to the job.
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Asymetric would be a rail or track on one side, the other side would look very similar to the current.
Tracking currently.
*I program the gcode to start with a complete outside trace of the job, if it does not end up right where I started I would re-align it, but I only ever had issues when in testing. I feel I run it pretty hard as well and no moving around.
*Maybe there is a good way to align the side plates we have not explored or even checked. I measure the X rails when I put it together to make sure they are the same length to the best of my abilities. Maybe the side plates need to get measured against the table instead? I have had a few LRâs a couple rebuilds and a couple moves. It still seems to track true for me. I also make sure that I am within a mm or two when a full bed sized rectangle is marked outâŚextremely square starting point. 1/8" gap between the plates and table or less.
*I have the vac hose and cords hanging from my side plates.
- What really needs to happen is I need to actually see on that is not tracking to find out why it isnât. Might have to quarantine and come out for a visit to one of you guys.
It will never track true by hand, never. You will always need to drive it with the steppers. This is true of any CNC, while it can be close enough for some giant build the electronics will always be more true/accurate.
Just to be clear, good place for ideas, I am not doing anything to the LR in the near future. I am trying to squeeze in some time for a new Zen first. With covid I canât bring in any help so my CAD time is limited.
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