The position of the router seems to make the noise worse when itās not centered ? Its not binding as much as it was which is good. I checked for square and ran the calibrations, its 0.42mm off on squareness and all other movement seems spot on.
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The Z- should lower the router. Iāve seen that issue mentioned prior but donāt know the details. As for the sound, from what I could hear (Iām in the shop with the longmill and dust collector running) it is similar to mine when I had the anti-backlash nuts too tight.
When you talk about the backlash nuts being too tight, are you talking about the 2 screws holding it in place or the one adjustable screw ? I have adjusted the 2 screws multiple times trying multiple configurations i.e. top one looser than bottom and vice versa and same tension etc. Just not having any luck. Maybe the machine does just need to be broken in. I was going to run a gcode of something simple without actually carving anything, a mock run if you will, just to see how the cnc handles and sounds.
Just to be clear here. This is just my opinion gathered from the last year of getting to know my machine.
There is one bolt on each one that needs to be adjusted. I would loosen them completely (but not out) and then move the router to see if the sound goes away. Then tighten them just enough to take any play out of the gantry. It only takes small turns to adjust. Do the Yās together and then move on to the others
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@Swinly, @lowhillcnc Hey Lonnie & Wade - The direction of the Axis movement can be changed in gSender firmware settings- check this link to this post from Kevin at Sienci: Z axis movement in Gsender - #8 by KGN
Steve D.
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I have posted this a few times and it seems to work, at least in my case. I was having strange sounds coming from the unit and I tried everything, after talking with the trouble shooters at Sienci labs my problem was solved so I will pass it on. I was able to turn both of my Y axis lead screws by hand with no effort at all and thatās not good. what I needed to do was run the gantry all the way forward till it stalls, as said above it sounds bad but it squares up the unit, then I backed off the gantry far enough to get to the backlash adjustment screws on the y axis. Turn the adjustment screws just enough so that the y axis lead screws were hard to turn by hand and that took care of my issue.
Canāt hurt to try it.
Good luck
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Thanks for reaching out Steve.
I found the place to make the changes under the āfirmwareā tab. All good now.
Thanks again.
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Hi Mike,
Thank you for that information. My lead screws were very easy to turn. I snugged them up like you suggested and have been running the break in g-code from IDC Woodcraft, I will attach the gcode file here for anyone else wanting to use it.
Ivāe been running for about 30 min now and no binding as yet, touch wood. Still some noises but sounding quite a bit better. Iām waiting on some dry lube to apply to all moving parts and hopefully that will just make it even better.
Thank you for taking the time to share your knowledge, very helpful.
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It sounds to me like youāre speed rate is set too high. So when the steppers try to move, theyāre taking off it the max speed which is too fast for them. If this is a gerbil machine check $110, $111 and $112. Drop them too 500 and check that. Also, look at your acceleration.
@lowhillcnc Wade: Where did you get that file?
@tcartner With respect, there is no reason on a properly adjusted Mill why the max feed rates should need to be reduced from the defaults to 500mm/min, if that is what you are advising. 
I know Garrett Fromme from ICD Woodcraft has one, I think that is where it is from. Do you see a problem with it?
@MikeH I defer to Garrettās superior knowledge. I was not trying to imply that there was a problem. I was more curious about its source. (I just downloaded Garrettās file and you are right. That is the one you are using.)
What had me asking was @tcartner / Tylerās comment about feed rates. I respectfully disagree with his advice, but I wanted to see what feed rate was set in the file. There is no feed rate set in that file. Others here more knowledgeable than me will know what that translates to. It may mean that it translates to running the Mill at its maximum default rate, which is 4000mm/min in X and Y and 3000mm/min in Z. Those speeds should cause no issues, certainly not the issue you are experiencing.
All that said, I donāt have a good solution for you. I would suggest that if the advice you have received here does not satisfactorily address the problem, open a support ticket with Sienci. Iām confident that they will help you out.
edit: I finally noticed that there really is a feed rate in the file. The initial G0 command sets all the subsequent moves to the max rate set in the eeprom, since there is no G1 F* command to change it. Sorry for the oversight.
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I see you mentioned getting dry lube. I had the same issue after putting together you 30X30 Longmill. My fix was I use 3-In-One oil (Light coat) on the acme screws (all three axis) and all the noise was gone.
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Hey guys just to confirm, yes , it is the g code from Garret.
I used bicycle chain dry lube and it has made a difference but not eliminated the noise. Iāll run it a little more and if no improvement I may try a light dose of 3 in 1. I saw another chat advising against 3 in 1 due to dust sticking to it gumming up the moving parts.
Hi there. I donāt have one of these machines but a couple of things caught my eye in this paragraph.
I would guess that the gantry system is designed to take the weight of the spindle/rounder wherever it is located on the gantry. It is in the nature of CNC work that the spindle can traverse easily from any part of the work area to any other part of the working envelope. If a positional change of the router causes the issue described to get worse as the router moves away from its own centre of gravity along the X rail, I would respectfully suggest that assembly could do with tweaking. I would aim for the sound to be the same along the length of the rail.
This is not correct. A measurement of 4/10mm out of true will cause you issues. I am assuming you mean the X rail is out of true in some way. I donāt know how you have determined that but it would help to know how it is out. If the X rail is leaning in any direction and is not perpendicular to the baseboard, you will experience tramming machining marks which can be difficult to remove if they are deep. These machining marks are always undesirable, especially where you need to create a fine finish.
If the lack of squareness is at where the X rail meets the y rails, the net result is that you will lose squareness in your cuts over a longer distance. I use a different machine and after taking 3 days to assemble it and declaring it good, I saw how poor assembly affect every piece of work I attempted to produce. I was fooled by the āHello Worldā sharpie test at the end of the assembly process. Of course, this tested nothing other than was the machine able to move the spindle in an X and Y manner. It said nothing about the pressure on the pen tip nor the accuracy of movement.
Coming back to the accuracy of movementā¦ if you try to cut a 2 inch square, what are the end measurement dimensions. Do the same with a two inch circle and check the measurements and the true shape of the circle. To solve my own issues, I disassembled everything and re-assembled it taking great care to true everything at every stage. I measured every join and angle for perpendicular to the baseboard and squareness. This process occupied another 6 weeks but the machines was now performing as expected. It speaks volumes that after that process, I was able to exchange the base board a couple of months later and it dropped in perfectly. It was used to increase the rigidity of the machine because it was aluminium and I wanted to machine aluminium.
I would definitely check the tightness of the acme lead screws. They should have no resistance to turning (no binding) because that will make the stepper motors get hot and wear quickly. I have not seen the assembly instructions and the machine creators will be able to tell you. It is usual to have some kind of thrust bearing on lead screws. They will help to take up backlash and keep the inertial moment of the lead screw (as it is starting to turn under stepper motor power) to within a reasonable parameter. A good idea is to try to remove the tendency for the lead screw to snatch on startup and be tight enough to reduce any inherent backlash (motion lost in the system before the next part moves) by ensuring the fit of the lead screws.
If you cut the test pieces which I suggested, please let me know how they worked for you.
I found that the stuff you use on router bit bearings (standard tool oil) works quite well. Use on Z-guides as well.
Also visit this video: LongMill V-Wheel Tuning [Annotated Clip] - YouTube
I thought my wheels were good to go. Come to find out they need to be tighter than you think.