Wiggle in long y axis lines

I have a consistent “wiggle” in all straight lines across the y axis. X is fine, straight… i have adjusted various things trying fix it to no avail. Why is this happening?

Could be chatter from going across the grain, little more rpm and a little less speed…

Im doing a large sign. It already is taking nearly three hours. Im using easel and a 1/8 on a fairly detailed sign, it has two large fish, a cabin, and 8 2"letters. But i guess good things come to those who wait, ill try slower next time.

wobble is actually on X
But… same difference.

That is not cross grain cutting, check your eccentric nuts…

How much of the bit is sticking out? Do you have runout (tip of the bit wobbling)?

I supose that could be an issue. Bit has 1/4 inch shank though. (Onsrud)
Uploading 20151025_151244.jpg…

I would make sure everything is tight…may not be the bit…I personally run 1/8" bits with 1/8" shank.

Im waiting on them to arrive, im working with a very limited selection… slow shipping and an impatient sign maker.

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While i have your help, how tight should v wheels be? I have mine set to where i can just spin them by fingers. Not free, but not too snug that they wont move if you rub them.

Mine are pretty snug…It is difficult for me to move mine by trying to spin with my fingers.

Are the wiggles or errors always in the same physical spot on your machine? If so, the problem may be mechanical - Check the makerslide rails and V wheels for dents or bits of sawdust stuck on them.

Are the errors always in the same part of the job, but not the same physical part of the machine table?

  • If so, the error could be in the gcode - this is outside my experience so other can assist with this.

Is the location of the error in a spot where the tool is under extra loading? For example when cutting “full width” instead of only half the width of the tool.

Does the error immediately correct itself or is the error reflected in the remainder of the job?

The more info you can provide, the better your (and our) chances are of finding the solution.

Im just going to answer these in order,
The error henceforth known as “the wiggle” appears in all long lines on Y axis ( borders mostly )

I obsessively clean my v wheels and rails with an old toothbrush so I don’t feel debris are an issue.

The wiggle is consistent throughout job. On all Y lines of any length long enough to show a variance. But NOT in smaller movements, like detailed sections of the carve or lettering. ONLY in long lines.

I can sometimes see slight movement on the router when Raising/lowering the z axis. so I wonder if my lead screw has some imperfection in it…

Thats all Ive got at this time. Thanks for helping me answer the right questions @DavidWestley I look forward to your thoughts on this.

Those are weird wiggles in that they have a large slope and are very nocticeable and are consistent all the way across (meaning not a problem with just one side of the x axis). I would cut a long test line across the y axis, with my hand on one of the x axis motors. That pulley should not move and you should not feel any stuttering or noise (you might feel a hum like it is holding position and this is normal). If that pully moves at ALL, you might have an interference issue.

You could perform this in the air without actually cutting but it would be more useful to have it cutting so you know you still have the wiggle and that that added stress on all the motors more closely represents the EMF Noise model you are expereincing in your sign project.

I am confident you’ll chase this down. But try this test to see if you see any stutter or jump in those x-axis motors during a y only cut.

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Will do, taking off from my machine for a few days. Ill post results as soon as I can. Thanks.

I think i have solved this issue. I didn’t run straight lines yet, because i was feeling pretty confident and had a dart board sign i really wanted to cut :smile:

I spent about an hour just fine tuning assembly of v wheels cleaned, lubricated, and reassembled with loctite blue removable. and redid spindle setup. To make sure everything was square and tight. I ended up after lots of sliding around going with v wheels set to where they will just… just… spin free to the touch.

ALSO, AND THIS WAS PROBABLY A HUGE ISSUE. HENCE THE HUGE TEXT… my gantry was out of whack. I have limit switches attached and soldered, but never wired them up. I had crashed the rails a few times and it was nearly .5" off on one side. I checked this using a square at gantry corners with x axis arm pulled all the way to bottom. Then just carefully adjusted them to even, by hand.

I then ran it at 3’ intervals all over, for awhile. No stalls, no grinds, just smooth sailing.

So, SOLVED. Take care with assembly and alignment of gantry. Use proper tension with eccentric nuts and v wheels.

I will run a straight line or ten after this carve im working on is done just to be sure. But i feel good about the rework.

I didn’t want to start a new thread, but i thought one of you experts may see this reply…

I have a V wheel that doesn’t move and is stiff. it seems to wobble and over tighten, Bad eccentric nut? over tightened? Is just ordering a replacement the thing to do? I have messed with it a lot… it just seems off, every other one works flawlessly. this is bottom left if your looking at the front of the spindle. anyways thanks as always for your input!

final on this sign… they loved it. wobble and all. Hand painted the lettering and stained it with a light oak spray can.

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I would say for you to take the v-wheel off to inspect it…I’m thinking you might this issue:

If that is the case, it should be an easy fix, or you could try contacting Inventables for a replacement, but that might take a little while for them to ship out.

That post is a little off, nothing to do with delrin nut. I think they just meant thr v wheel, not sure. I did remove and reset it, i think i just need a new assembly, bolt, nut, and all. Thanks!