# Roughing vs Detail pass slightly off **URL:** \ **Category:** Uncategorized\ **Created:** [December 31, 2021, 6:45pm UTC](https://forum.onefinitycnc.com/t/roughing-vs-detail-pass-slightly-off/9934 "2021-12-31T18:45:16Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![Indyboiler](https://avatars.discourse-cdn.com/v4/letter/i/ebca7d/32.png) [@Indyboiler](https://forum.onefinitycnc.com/u/Indyboiler)\ **Post date:** [December 31, 2021, 6:45pm UTC](https://forum.onefinitycnc.com/t/roughing-vs-detail-pass-slightly-off/9934/1 "2021-12-31T18:45:17Z")
I’ve started experimenting with 2-stage carves, and it looks like the roughing pass is carving just a bit deeper than the detail pass. I used a 1/4" upcut for roughing, and a 1/2" 90 degree V bit for detail, both at a depth per pass of .09375. Between passes I am probing for Z only with the Onefinity touch probe. I found a [thread on Inventables](https://discuss.inventables.com/t/roughing-pass-carves-deeper-than-detail-pass/114138/23) that looks like a similar issue, but I did not see a definitive answer as to how they solved the problem. Any advice on what could be causing this? ![IMG_2466.HEIC](https://us1.discourse-cdn.com/flex022/uploads/onefinitycnc/original/3X/e/5/e5e7a77883613cf90be4d2f581e387cca5760176.jpeg) ---
**Author:** ![JimHatch](https://sea2.discourse-cdn.com/flex022/user_avatar/forum.onefinitycnc.com/jimhatch/32/3928_2.png) [@JimHatch](https://forum.onefinitycnc.com/u/JimHatch)\ **Post date:** [December 31, 2021, 7:09pm UTC](https://forum.onefinitycnc.com/t/roughing-vs-detail-pass-slightly-off/9934/2 "2021-12-31T19:09:18Z")
> [@Indyboiler](#): > > I used a 1/4" upcut for roughing, and a 1/2" 90 degree V bit for detail, both at a depth per pass of .09375. Between passes I am probing for Z only with the Onefinity touch probe. Do you have the depth of cut the same? Are you placing the probe block on the same part of the material for each Z-probe? ---
**Author:** ![YXYJack](https://avatars.discourse-cdn.com/v4/letter/y/c67d28/32.png) [@YXYJack](https://forum.onefinitycnc.com/u/YXYJack)\ **Post date:** [December 31, 2021, 7:18pm UTC](https://forum.onefinitycnc.com/t/roughing-vs-detail-pass-slightly-off/9934/3 "2021-12-31T19:18:50Z")
If I understand the issue correctly, the roughing pass is cutting a small amount deeper than the finish pass? If yes, does the gcode for the two passes have the same Z-depth in simulation? That would separate it into a CAD/CAM problem versus a gcode sender/mechanical problem - such as what Jim asked. -Mark ---
**Author:** ![Indyboiler](https://avatars.discourse-cdn.com/v4/letter/i/ebca7d/32.png) [@Indyboiler](https://forum.onefinitycnc.com/u/Indyboiler)\ **Post date:** [December 31, 2021, 7:49pm UTC](https://forum.onefinitycnc.com/t/roughing-vs-detail-pass-slightly-off/9934/4 "2021-12-31T19:49:41Z")
Yes, my depth of cut for the entire pocket is .05. I am starting with the probe on the bottom left corner, probing for XYZ. After I change bits, I flip the probe over, touch the recessed side to the bit and set it on the corner, then let it probe for Z. ---
**Author:** ![JimHatch](https://sea2.discourse-cdn.com/flex022/user_avatar/forum.onefinitycnc.com/jimhatch/32/3928_2.png) [@JimHatch](https://forum.onefinitycnc.com/u/JimHatch)\ **Post date:** [December 31, 2021, 7:54pm UTC](https://forum.onefinitycnc.com/t/roughing-vs-detail-pass-slightly-off/9934/5 "2021-12-31T19:54:11Z")
You can verify that the settings for the probe block are correct by probing on the underside (the recessed Z-only side) for both bits. There may be an error in the machine setup vs the block’s construction that results in a different resulting “top of material” calculation when probing the different sides. The other thing to do is check the GCode like @YXYJack suggests to see if it’s a CAM issue. ---
**Author:** ![Indyboiler](https://avatars.discourse-cdn.com/v4/letter/i/ebca7d/32.png) [@Indyboiler](https://forum.onefinitycnc.com/u/Indyboiler)\ **Post date:** [December 31, 2021, 7:54pm UTC](https://forum.onefinitycnc.com/t/roughing-vs-detail-pass-slightly-off/9934/6 "2021-12-31T19:54:44Z")
Hi Mark - I am completely new to the CNC world. Could you explain further how I can compare the 2 gcode files to determine if they have the same z-depth? ---
**Author:** ![alden](https://sea2.discourse-cdn.com/flex022/user_avatar/forum.onefinitycnc.com/alden/32/161_2.png) [@alden](https://forum.onefinitycnc.com/u/alden)\ **Post date:** [December 31, 2021, 11:26pm UTC](https://forum.onefinitycnc.com/t/roughing-vs-detail-pass-slightly-off/9934/7 "2021-12-31T23:26:31Z")
Try a ball nose bit and see if that cleans up better than the vbit. ---
**Author:** ![YXYJack](https://avatars.discourse-cdn.com/v4/letter/y/c67d28/32.png) [@YXYJack](https://forum.onefinitycnc.com/u/YXYJack)\ **Post date:** [January 1, 2022, 7:53pm UTC](https://forum.onefinitycnc.com/t/roughing-vs-detail-pass-slightly-off/9934/8 "2022-01-01T19:53:45Z")
> Blockquote I am completely new to the CNC world. Could you explain further how I can compare the 2 gcode files to determine if they have the same z-depth? Your CAM program should have a simulation feature. I’d use it to show both toolpaths together, then zoom in on the section where you are getting a step in Z-height and see if the step is shown in simulation (you can also use a gcode viewer like [ncviewer.com](http://ncviewer.com)). -Mark