Lowrider 3 traming

Hi every


I am having a weird tramming issue, I have gotten the machine trammed on one side but the other is way off. I did not see any Tramming instructions in the build manual. I got it trammed by adding shims to the router mount. but looking on the surfacing results it looks like the right side is correct but the left side is out of tram.

Any suggestions to how to correct the issue would be greatly appreciated.

Thanks Ron

I you really want it perfectly trammed, you want your spindle and bit to be perfectly perpendicular to X -Gantry plane of travel.

You want that plane of travel, as a starting point, to be as close as possible to the plane of your table, which can be adjusted according to LowRider CNC V3 - V1 Engineering Documentation

There’s a thread related to this here: LR3 traming - X and Y direction which got spun off from Pocket with a T-slot bit - #34 if you want to do some light reading on the subject :slight_smile:

If your tool is perfectly perpendicular to the table, surfacing should come out correct. Leveling the gantry and the table as close as possible should minimize the amount of material needs to be removed on the first surfacing job.

Edit: Looking back at your picture, it looks like I can see lines in your surfacing job on the right in some spots too:

you say it’s “trammed on one side”, but are you sure the tool was contacting the table at those points? Maybe the spots where you don’t see the lines is just where the tool didn’t contact the spoilboard?

Otherwise, the spots where there are lines being mixed like that leads me to believe that maybe your core has some movement in it or something where it’s not consistently making contact everywhere, or your table has some weird plane where it’s causing different angle of contact in other places.

If you want those lines to go away on a wide bit like that, though, I would start with making sure the tool is perfectly perpendicular to the X Gantry.

Others will likely follow along to tell you why it’s probably not that important for most things, like smaller bits, so you don’t necessarily need to chase that unless it matters for your project types, or your OCD :slight_smile:

Also have a look @jamiek surface page. I have found on both of my LRs that its best to surface in the N direction. His code will only cut one direction. It takes a little longer but leaves an extremely clean finish if you are close on your tram.

True North or magnetic North?

Ron, I might be envisioning something you’re not saying. If I’m hearing you correctly, you trammed to the right side of your photo, and it’s off on the left side. Or you trammed it in the center?

Reason I’m asking to maybe help the people with more specific info on what was done.

In my simple mind, I’m thinking two things.

  1. A small twist in the gantry might cause this, I’m curious to see if my hunch is confirmed by the smarter people.
  2. If you trammed on the right side, and it’s not off something terrible on the left, then tramming in the center would make it less noticeable, or split the difference on each side. Which might be the easy “fix”, but it’s also like using duct tape, on something that should be glued or screwed, IMO.

But focus on what the knowledgeable people say, I’m more or less testing my troubleshooting thoughts, to see if I’m becoming more knowledgeable.

This is my thought too. Check that all the rollers, two on left, four on right, are in contact. I’m not sure what could cause the twist. Check visually if you can see any twist in the X gantry, or if the top and bottom X rails are not quite parallel.

If you loosen all the bolts on the front strut plate slightly then it will loosen the grip on the rails a bit. In this state you might be able to twist the gantry by hand a bit without having to disassemble and reassemble. Then once it’s straight, tighten again. (This is probably going to be a pain because the nuts are not captive and they are a little hard to reach.)