Two Sided Projects

I’m making nesting coasters and coaster bases.
They require milling on both sides, and for those sides to be well aligned.
I’ve been fighting alignment issues for 2-months now, would love any suggestions…

I’m using Aspire
I have an X-50
I’ve checked that the 1F cuts an accurate circle and square.
I’m using material that is EXACTLY the correct size in X, Y and Z
I’m using 22" wide by 5.5" tall by 0.65" thick pine (I’ve moved back to pine to stop wasting expensive hardwood).
I’m using a 1/4" downbit
I use the touch probe for the top side cut, and was not adjusting anything when flipping, since I was using the dowel method. (later when I used a jig I have tried both using and not using the touch probe on the back side.

When I create my project(s) in Aspire I use the 2-sided option, and I make sure to do the entire design on one-side, then move the backside vectors using the “move to other side” function. When I preview the design in Aspire it looks perfect.

When I complete the project, each side is carved correctly but NOT aligned to the other side. usually off in X but sometimes in Y as well. Seems different each time I carve.

At first I used the dowel/alignment hole method using offset holes to ensure accuracy. Wasn’t getting good results.

Second I built a jig to ensure that the material is always in exactly the same place.

Third, when I flipped my material over I reset my X/Y/Z position using the touch probe.

In all of these situations, I can not get the two sides aligned.

Any suggestions anyone? (this is KILLING ME…)

Bill Butler

Normally you do not reset X,Y when you flip the part, only the Z might be re probed because you want to probe the same side both times - so when you probed the top for side 1, flip the part, now side 1 is on the wasteboard so you probe that level, this ensures the finished part is the correct thickness.


In addition to Wayward’s note you might consider whether your machine is a parallelogram as that will throw geometry off as the carve moves farther away from the zero reference.

There are some good forum discussions here on the subject that helped me.

In short, free form and small carves are not generally as noticeable but large/nested carves often require more accurate X,Y,Z geometry.

I learned from Mark Lindsay, works great: Two Sided Machining 1 - Part 30 - Vectric for the Absolute Beginner

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Thanks Kerek.
I originally did NOT reset X, Y or Z, since it was affixed into a jig (x/y) and was the same thickness as before. I also made sure the material was EXACTLY the same X dimension as the Vectric file (since I was flipping on the X axis). Still had the problem. So re-probing was an attempt to troubleshoot, didn’t help.

Thanks for the suggestion!
I looked at the forums and grabbed my tools and checked for that, looks square to me. Maybe 0.007 off, at the most.

Thanks Craig!
I watched the same video and used his techniques when designing my coasters.
I used the alignment holes as first method, but didn’t work.
Then I built a jig (basically pegs in my spoilboard) to check but that hasn’t worked either.

The problem with the alignment holes is that I plan on making lots of these coasters, and if I assume I won’t always get the material cut the exact same length as the piece I used to put the alignment holes in my spoilboard, doesn’t seem to be a way to set this up to be repeatable, which is why I went with a jig.


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I have had best results when (1) setting my zero in the center of the block and (2) ensuring that the block is exactly parallel to the X axis.
I use a vice to ensure repeatable parallelism. And I reset the zero on both sides. See details on the Fusion 360 post.

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What I’m seeing is “creep” between each item on the second side.
I’m cutting 5 round coasters out of a 5.5" high and 24" wide piece of pine.
As it cuts the second side, each coaster’s registration is off a bit more.
I’m starting to suspect something around the travel speed between each coaster, since the coasters themselves are cut correctly. I’m wondering if either something in the post-processor or a setting on the 1F is too high around moving the X axis when not carving… I’ll have to keep looking…

There were slipping problems with firmware < 1.0.8. Make sure you are up-to-date.

Also note that a lack of parallelism with the 1F axis will cause the slippage to increase between each piece. I draw a simple project in Fusion 360 to illustrate: a symmetrical piece, rotate it (a lot for illustration purposes) and cut the holes again. You can see that the slippage increases.


Here is a video I made a while back. It deals with zeroing to the center of a circle but it also demonstrates setting up bump stops to make sure they are perfectly aligned with the X and Y axis travel. It almost sounds like that it the root of your alignment problem.


Charley’s bump stop method works great and there are numerous ways to accomplish.
If you do not want to mount the stops you can use a V-Bit, 30 degrees or less, and make a line on x and y on your wasteboard. Use that to align your stock. Before I upgraded to the X50, the line I made a year before was still accurate the day I removed to rail to upgrade.

Just to make sure you know, if you have the joystick, you can hold the buttons on the top to restrict axis.

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Thanks Ben. I have checked that my machine is square and not a parallelogram.
I suspect now that I have a mechanical issue with the 1F, perhaps one of the Y axis motors isn’t working…

Thanks. I am using stops on the machine to keep the material in the same place every time.
I have dog holes in my spoilboard and use them to align the board, and I make sure the board is EXACTLY the size as is in the design file. I’ve also tried flipping the material both horizontally and vertically. I am not suspecting a problem with one of the Y axis motors…

I have not heard of many mechanical failures on the forum so, while possible, it is not the most likely scenario.
Seeing your response on the parallelogram, that is not my concern at all. I suspect the parallelism between the edge of the raw material and the 1F axis, not the angle between X and Y axis.

Let me try to explain… it’s perfectly clear in my mind but I’m not a machinist (or a native speaker) so… here’s the most simple explanation I can muster. If cut you a straight line along the X axis, the line is not parallel to the edge of your raw material but parallel to the 1F own X axis.

If the edge of the raw material is perfectly aligned with the 1F X axis, you flip the part, make a second cut at the same position, then the two lines will coincide. Success! But if there’s even a small misalignment between the part edge and the 1F axis, when you flip the part you are reversing the misalignment! The 1F will still cut along its X axis so the two cuts are separating from one another.

And, based on your description of the problem, I think that is what you are seeing.

When I mill 2-sided pieces, I ensure that the raw material edge is exactly parallel to the 1F axis, down to 0.05mm with a 3D taster or a test indicator. My experience is that the smallest misalignment results in the sort of creep that you describe.


Bill, I was having a similar problem using the 3 dowel method from the video. Every time I flipped my piece, I was off by 1/16" to 1/8". I tried many different three pin setups and it was always off.

I started using a two pin method and haven’t had any problems since. The two pins are placed in the centerline of the design on the left and right sides. Then I set the project up for a left to right flip. Viola…no alignment problems from the first try.

I just have to remember to keep the orientation of the project the right way and make sure I flip left to right.


Please try with a valid version of Vectric and see what happens. The version you’ve been using is a known pirated version that includes bugs and other software abnormalities and harms our software partners.
Other troubleshooting should be halted until a valid version is used.

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I received a suggestion from the forum which I was able to check this morning, and I believe I’ve figured out the issue.
It looks like my spoilboard is NOT aligned with the machine.

WHen I cut a line in the X axis and flip the board, I get the same error.

I do not know how this is possible, since I cut the dog holes in the spoilboard ON the machine, but clearly something with the machine alignment has changed.
So the X axis on the spoilboard was not aligned with the X axis on the 1F.

I will be re-cutting a spoilboard today to ensure alignment with the 1F and will test again using the method recommended in the forum.

I will advise if this fixes the problem.


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Great, keep us all updated.

Hey Bill,