Tramming issues resurface

I thought i had the machine trammed again but no luck. I spent 6 hours readjusting and rerunning with the same results. Ridges on both sides, essentially strips of raised wiid every couple inches. Did 100% stepover, 80%, 50%, 40%. Resurfaced spoilboard (which had no ridges) Adjusted via loosening the 8 black screws on the linear guide rails. Used my pwncnc tramming tool, still not trammed. Vwheels are only a month old, new bearings and linear guide blocks. At this point im just going to disassemble the whole machine and start over. Been using the machine for over a year and this seems to happen randomly every few months.

Also this is happening on 10 different workpieces and theyre not moving during surfacing.

Side note, when the machine is in the middle of the Y travel, wheels are snug, when jogged to the front end, they free float. Id assume if it was a extrusion wear issue, it would be the other way around. So somethings bent or misaligned.

Have a similar issue…saw video that demoed that his dust boot was pressing down at a 7-8 lb push…w boot off the witness marks almost disappear….not saying that is a solution but at this point I’m trying everything…JAC

I moved the workpiece over a few inches to see if the lines would appear at the original location, which would indicate an extrusion rail issue, but the lines moved exactly with the router, regardless of spoilboard location. I then changed the bit to another from the same company and the lines became almost invisible and i couldnt catch my nail on them. Very strange.

Dirty collet?
Any bit damage?

nope, all looks fine, it has to come down to tramming even if its better but still there with a new bit

Have you tried along the X?

It’s possible that a piece of sawdust or shaving of whatever you cut was causing the endmill to not sit properly.
This is why they sell precision collets now and why pro operators will fully remove the and clean the collet, nut and spindle between jobs on tool changes.

It’s sometimes hard to tell from a pic but to me your result looks like the top profile in my pic, view is looking towards +Y.

If that is what your surfacing looks/feels like then it doesn’t look like a tram issue to me. A bit tilted with the bottom to the left would leave lines like my bottom profile. The angled lines going the other way for bottom of bit tilted to the right.


If the bit was tilted with the bottom toward the front or back the profile would look like this.

All my examples are for front to back travel the way you did it.

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Im going to try the advice about the dust boot next, maybe it is pulling the router. I already disassembled the Z gantry, cleaned everything, replaced the two bearings at the top and reassembled.

Sounds like a plan, when I use my dust shoe I always make sure the bristles don’t touch the surface. It may miss more chips that way but if the bristles touch it can lift the router when it reverses direction.

I just added an 80mm watercooled spindle to my Longmill MK2(.5?) 48x30. That thing is heavy, pretty near 20lbs. (at least it feels like it). The Z axis can tend to slip down with all that weight. It was suggested to me to lock the stepper motors, so that they are always energized, even when there is no movement. If I remember correctly, I set $1=255 in gSender firmware. The motors will maintain their positions. I don’t know if this will help with your problem, but it’s worth a try.

I reread this thread do to a new post and I had a new idea of what might have caused this, not sure if you got it resolved or not.

Anyway I was thinking it could be some flex or something not tight enough and maybe that would cause the deeper cuts when moving toward the front of the machine and the shallower cuts when moving toward the back. Not knowing what your feed rate or pass depth was it’s hard to say but I think if the resistance of the wood caused flex or movement it might cause those lines with the top of the Z axis tilting a little toward the direction of travel i.e. ‘floating’ to the back and ‘digging in’ to the front.