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Post by billiam on Mar 31, 2020 18:38:26 GMT
I finished assembling my 35" Mega V but I feel like I'm not quite right on the rack and pinion meshing, especially on the Y axis.
If I apply light-medium pressure on the rack while tensioning its screws, I'm not able to smoothly slide the gantry along the Y axis without needing more pressure in some spots as it's either binding, or maybe the rack is slightly out of square and going further apart in sections.
Rapid travel is very noisy along Y with a lot of vibration, and you can hear a tak-tak-tak as the gear runs over the rock.
With only very-light to light pressure, the axis will bind and fully lock up while moving it manually.
How smoothly and/or quietly should the gantry be able to move with the motors unpowered? Powered?
Any tips (beyond the procedure is the assembly video) for getting set up?
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Post by timspec on Apr 4, 2020 6:25:45 GMT
curious to what ppl say about this, mine's a bit noisy too bit doesn't bind like yours. i've read you can use dry lube but haven't tried it yet. I was going to try and adjust the rack to give it slightly more clearance to see if that solves it. you might try the same. also make sure your pinion gears have proper clearance with the frame.
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Post by Bruce on Apr 4, 2020 16:28:54 GMT
This setup of the rack and pinon is a touchy part of the setup. Make sure you have the 6M washer installed as a spacer between the motor mount plate and the gantry. With the power off, loosen the rack a bit and make sure the pinon rides along freely and then tighten it down. Then power up and jog it around. It may take several adjustments to get it in line.
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Post by hogleghandcrafted on Apr 5, 2020 21:07:30 GMT
I squared the table. Pythagoras Theory worked and corner to corner on the structure is also within .5mm. I started to carve again and drift happened again. I shut it all down and checked the flows. Now, there is much play between both Y rails when manually running up and down. Loosen all screws and retighten, I assume? Always been a rattle at certain spots. Also, do you suggest dry lube on the rack and pinion? My next carve after adjusting the spacers did the same thing. Halfway through the whole pattern shifted left and then continued on the path. I see that the depths need adjustment, but I would love some guidance on correcting this pattern of jumping to the left. I have carved 17 times so far and only 2 paths have completed without exception. I am using waste material until it carves correctly and then replacing with sellable stock. Then on the next carve, my good stock is damaged beyond repair. Attachments:
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Post by billiam on Apr 7, 2020 5:20:00 GMT
Thanks, it's definitely been a challenge for me so far.
I did find that the rack itself is pretty flexible during installation, at the ends especially. It's easy to bend it out of shape.
I had a much easier time of adjusting it by first trying to find a distance that felt comfortable for one screw (not at the end) and replicating that with calipers at all the others.
I still don't know whether I should have more or less engagement than I have now, but I definitely have fewer areas that are harder to move through than others.
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Post by btreichel on Apr 8, 2020 16:26:46 GMT
I've been fighting with my x axis also. Its seems like it is sensitive to the rack screws, and also the tension on the motor screws. With the rack screws it seems that the tighter they are the more it seems to advance them into the pinion.
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Post by btreichel on Apr 8, 2020 22:45:51 GMT
Found out why I couldn't get the x axis rack and pinion not to bind. I forgot the stinking spacing washers that go between the two plates.
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Post by billiam on Apr 13, 2020 2:45:26 GMT
I'm still no good on getting this tension right, it looks like. Seemed alright, but then started skipping steps during a cut, and I can feel the axis binding a bit.
I'm not sure what to do, or what would indicate that it was more or less correct.
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Post by jginvc on Apr 13, 2020 3:56:59 GMT
I'm still no good on getting this tension right, it looks like. Seemed alright, but then started skipping steps during a cut, and I can feel the axis binding a bit. I'm not sure what to do, or what would indicate that it was more or less correct. I am having the same issue with the Y axis. Adjusted, readjusted, and re-adjusted again. Still losing Y axis steps. Spent 8 hours today trying to get it sorted out. There has to be a better way.
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Post by Bruce on Apr 14, 2020 2:01:44 GMT
Do you have the 6M washer installed as a spacer between the motor mount plate and the gantry?
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Post by billiam on Apr 14, 2020 3:10:48 GMT
Do you have the 6M washer installed as a spacer between the motor mount plate and the gantry? I do, but good thought!
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Post by Bruce on Apr 15, 2020 2:02:16 GMT
You could try adding a thicker washer or second one to existing washer to extend the offset of the motor mounting plate. It looks like a little more space for the gear to mesh with the pinion correctly is needed.
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hans
Full Member
Posts: 151
Machine: Other
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Post by hans on Apr 15, 2020 2:39:36 GMT
I have no suggestion for addressing what's ailing, but I did notice a couple of comments on this thread about people having "noisy travel" along with skipped steps and binding. I've done a number of jobs on my Mega V and have not had any skipped steps so I thought I might mention that movement on my unit is remarkably quiet. Z-axis movement makes a noise similar to my Carve King, but X movement at cutting speeds, but with the router off, is almost silent. Y movement, with two pinions active, is a bit louder, about as loud as the fan in the control unit. I hope this is helpful.
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Post by btreichel on Apr 15, 2020 4:02:59 GMT
You could try adding a thicker washer or second one to existing washer to extend the offset of the motor mounting plate. It looks like a little more space for the gear to mesh with the pinion correctly is needed. I forgot the 1mm washers between my x axis motor plate, and the carriage.That was 85% of my problems. So stick another washer in there. It's a 15 minute job (if yo work slow).
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Post by maronz on May 6, 2020 2:32:59 GMT
I have the same problem in the Y axis but this is what’s weird in the Y plus it moves smooth no herky-jerky no binding but in the Y minus it is jerky binding like the mesh is totally wrong on the gears
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