Accuracy, step 1 Pen

This topic contains 49 replies, has 8 voices, and was last updated by  Jeffeb3 2 months, 1 week ago.

Viewing 20 posts - 31 through 50 (of 50 total)
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  • #57826

    Bill
    Participant

    You’d have to build some sort of a wear factor into the piece of chalk, so it’d drop the Z axis as the chalk wore…

    #57828

    Jeffeb3
    Participant

    They make chalk holders that are spring loaded. Plus, it doesnt have to be perfect.

    #57842

    Bill
    Participant

    Another thing would be angle the chalk and rotate it as you go to minimize the width of the chalk line…

    #60217

    Mark
    Participant

    Re: pen mounts, here’s what we need: https://www.youtube.com/watch?v=HciNR-tskwQ

    I’d model it up, but I’d need some way to know exactly what the mating interface is. Is there an STL or something for it?

    2 users thanked author for this post.
    #95636

    kd2018
    Participant

    No matter how long I stair at the instructions (here and on the duel endstop page) I don’t understand what you mean..

    Now How do I write instructions?

    1-Measure the largest diagonals you can to the X1 and Y1 home positions.

    But there is only one diagonal that goes to x1,y1 ?

    Maybe it would make things more clear if you could illustrate exactly what you mean?

    I’ve attached a quick mockup of the rails and the way I see my coordinate system at the moment. I’m guessing that I’m visualizing something incorrectly.

    #95646

    Ryan
    Keymaster

    From your picture use the machine to draw the blue square, Measure and compare D1 vs D2.

    #95652

    kd2018
    Participant

    Ryan,

    I hate to be a pest but would you mind clarifying further?

    Offset the endstop that has the short dimension … So if the X1 diagonal was 1mm short…

    So per my drawing above, which diagonal is X1 ? Why is it X1? It takes at least two points to figure which diagonal is which (technically 4)!!

    I gotta tell you I’m disturbed with myself that I’m still not understanding what you mean and I know I won’t be able to let it go! Can you confirm this :

    X1 rail = bottom rail, X2 rail = top rail
    X1 endstop = bottom left, x2 endstop = top left
    y1 rail = left rail, Y2 rail = right rail
    Y1 endstop = bottom left, Y2 endstop = bottom right

    In the very beginning we moved the two endstops on the bottom left corner (what I’m calling x1,y1 endstops) a hair closer to the bottom left corner, correct? The endstops at the top rail (x2) and right rail (y2) are “fixed”? M666 offsets off just the bottom left corner alone?

    #95656

    Jeffeb3
    Participant

    It’s hard to describe coordinate frames in text. This is tough without a whiteboard.

    First, from Ryan’s instructions, I think his X1 and Y1 are in different corners. So when he says the X1 diagonal, he means the diagonal that starts or ends on the X1 endstop corner. Keep in mind the motor you hook up to X1 or X2 is arbitrary, so everyone’s is different.

    But, your drawing is better, so let’s use that.

    If D1 is shorter than D2, you can adjust it by offsetting the X2 endstop. This wil move the top side of the rectangle to the right, making D2 shorter and D1 longer.

    You could also offset Y2 to move the right side up which would also make D2 shorter and D1 longer. You may be fixing square but making it less parallel to the rails, but remember that the reason you’re adjusting this is because the rails are not square. Hopefully, these are small adjustments anyway.

    3 users thanked author for this post.
    #95698

    kd2018
    Participant

    Thank you Jeff, that was helpful.

    I wanted to note that Configuration_adv.h states “… X_DUAL_ENDSTOP_ADJUSTMENT … is applied to the X2 motor.” Ryan’s instructions refer to setting X1,Y1 offsets. I think this also contributes to my disorientation.

    And for the record I also want to clarify that I do in fact understand how to rack a rhombus back to square! I wouldn’t want y’all to think I’m that slow! 🙂

    #95700

    Jeffeb3
    Participant

    And for the record I also want to clarify that I do in fact understand how to rack a rhombus back to square! I wouldn’t want y’all to think I’m that slow! ?

    I’m sure you do, but for every 1 person who asks, I have to imagine there are 10 that don’t. Plus, you and I probably think of things differently, so I tend to go from the basics so everyone is on the same page. (Sometimes it’s condescending or preachy, but there are costs to a text only interface).

    #95701

    Jeffeb3
    Participant

    I wanted to note that Configuration_adv.h states “… X_DUAL_ENDSTOP_ADJUSTMENT … is applied to the X2 motor.” Ryan’s instructions refer to setting X1,Y1 offsets. I think this also contributes to my disorientation.

    Yeah, I haven’t looked at how this works. I assume a negative offset would move X1 in the positive direction, so it wouldn’t clobber the endstops. At any rate, that also probably needs some clarity.

    I think most of those instructions were when we assumed it would be a niche setup. From the perspective of the forums, it seems like a lot of people are doing it. But maybe it just the setups that generate more posts…

    #95702

    kd2018
    Participant

    @Jeff, I completely understand where you’re coming from. I didn’t mention that because I felt you were condescending in any way, but only because I’m new around here and didn’t want you guys to think I’m a dope.

     

    Maybe this will help folks in the future.

    *Note: X2 endstop and Y2 endstop need to be on adjacent corners in order to be capable of adjusting both diagonals through with firmware. Not strictly required.

    #96241

    Bill
    Participant

    I think it’s a nomenclature issue. X/X1 vs X1/X2.

    #96245

    kd2018
    Participant

    But it is a relevant distinction.

    As far as I know the firmware for the rambo only adjusts the motors plugged into the x2 and y2 ports. And from what I understand it won’t adjust them below zero. So to get the results that you’re expecting I think it’s important to understand the rules we’re playing by.

    If you expect to be able to adjust both diagonals “directly” then you need x2 and y2 endstops at adjacent corners. If they’re on the same corner, like I had originally assumed, or opposite corners you’ll only be able to tweak one diagonal. In either of the latter two scenarios you can still get the job done but you’ll need to take a slightly different approach than what Ryan described in his instructions.

    [EDIT – Sorry I misunderstood your reply]

    @bill, that’s what I thought at first as well but the instructions did start out saying X1, Y1, X2, and Y2. The comments in the firmware also refer to them as 1 and 2.

    #96346

    Ryan
    Keymaster

    I can go back and change all the pictures to match what the firmware says or should I do it to what the boards have printed on them (every board is different)?

    The point is one can be adjusted if it is not the one you need you can just swap where it is plugged into the board. So you are kinda getting lost on labels and missing the idea. As for negative offset, no you can not drive it past the stop block, you would offset the other stepper (by swapping where it is plugged in), or moving the block back one tooth.

    I understand where you are coming from  and what a very exact precise tuning manual it does not work here, we do not make complete kits built the same exact way. As soon as someone builds a machine facing the other direction it is all lost or what about when it is used on a LowRider. If you keep it general it applies to all builds, worst case you apply and offset and the discrepancy gets worse, 2 minutes lost, no big deal.

    I have only ever needed the offset one time on one stepper, getting each side within 2mm on a standard build is usually close enough.

    #96372

    kd2018
    Participant

    I can go back and change all the pictures to match what the firmware says or should I do it to what the boards have printed on them (every board is different)?

    I’m not sure if that is rhetorical but I’d vote go by the firmware, headers labeled extruders are wrong at this point anyway. Again, just my vote.

    The point is one can be adjusted if it is not the one you need you can just swap where it is plugged into the board.

    Note we would also have to reverse the pins. The RAMBo connectors on the board only go in one way, so reversing could be a PITA depending on how someone made their motor cables (eg soldered and heat shrinked).

    So you are kinda getting lost on labels and missing the idea.

    Well I got your idea now after I matched up my labels with yours 😉

    As soon as someone builds a machine facing the other direction it is all lost

    That’s my point. The instructions make certain assumptions without letting us know what they are or that assumptions were even made in the first place. Speaking just for my self, it would have been helpful for me to have had an illustration like the one I put together in post #95702 above. If it doesn’t match the coordinate system someone setup for themselves at least they could see they’re starting from a different perspective than the instructions.

    None of it is complicated. If we’re smart enough to get this far in building a homemade cnc machine we can figure out how to square some rails. I personally just got lost in trying to peek inside the mind of Allted !

    #96375

    Ryan
    Keymaster

    Note we would also have to reverse the pins.

    My wire kits fit either direction. This is another one of those, if I mass produced a complete kit they would be keyed but since I don’t non-directional is easiest.

     

    None of it’s complicated. If we’re smart enough to get this far in building a homemade cnc machine we can figure out how to square some rails. I personally just got lost in trying to peek inside the mind of Allted !

    I will look into it the next time through the instructions. As it currently stands by far the largest issue with the dual endstops is people not getting the actual switch on the correct side. Maybe when I clarify the instructions on this simple test it will clear up what you had an issue with as it forces you to check (takes 10 seconds).

    I really do understand your perspective but from my side being more vague seems to really help people just get in and try it. Nothing will get ruined or destroyed and the point of an inexpensive build is to learn without fear of destroying several thousands of dollars worth of machine. As an example the second I labeled the tension bolts on the middle assembly I got flooded with a new type of question “my Gantry is doing ####, Which bolt do I turn to fix it?”. Instead of asking they easily could have just turned the bolts to see what happened like they did before I gave them specific names. I have intentionally made some things more vague.

     

    #99429

    John Boiles
    Participant

    So does @kd2018‘s diagram in post #95702 correctly capture which sides should be adjustable? In my understanding, it doesn’t really matter but if you use #kd2018’s orientation then you can more easily use the diagonals trick to verify things are square. Is that correct?

    In my build I set the X1 rail as the rail closest to Y=0 (like the diagram he included in #95636)

    #99440

    kd2018
    Participant

    *sigh* doesn’t look like it’s right… The firmware says x2 and y2 ports are adjusted but after messing with things last night it looks like it actually what ever is plugged into x1 and y1. Gotta love it when this stuff is consistently inconsistent.

    #99442

    Jeffeb3
    Participant

    Feel free to make an issue or PR in Marlin. It can only get better from here.

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