# Steps/unit -- right or wrong? **URL:** \ **Category:** Software\ **Created:** [May 30, 2015, 11:31pm UTC](https://forum.lulzbot.com/t/steps-unit-right-or-wrong/1830 "2015-05-30T23:31:12Z")\ **Posts on this page:** 1\ **Showing post:** 3
**Author:** ![Anonymouse](https://avatars.discourse-cdn.com/v4/letter/a/ecccb3/32.png) [@Anonymouse](https://forum.lulzbot.com/u/Anonymouse)\ **Post date:** [June 2, 2015, 3:25am UTC](https://forum.lulzbot.com/t/steps-unit-right-or-wrong/1830/3 "2015-06-02T03:25:35Z")
> [@Orias](#): > > It is supposed to be 100.5. The extra 0.5% steps per mm is there to compensate for thermoplastic shrinking. It’s what we’ve used across the entire LulzBot 3D printer line, for quite some time. I’m not buyin’ it. Different types of plastic shrink different amounts, so .5% seems a little arbitrary. Also, it’s a well known fact that external dimensions of parts printed on lulzbots tend to be a little bigger than they are designed to be (especially in x and y), so if the idea is to make the part closer to the design dimension, you should lower the steps/unit, not raise it. Perhaps this is why all these people have dimensional inconsistency. > [@LulzBot MINI dimensions off.](https://forum.lulzbot.com/t/lulzbot-mini-dimensions-off/1545/5): > > It was brand new 2 days ago, I haven’t done enough to mess up the extruder gear yet. (I checked anyway & it looks fine) As it is, you may be right about the filament diameter. That being said, regardless of what is different, It’s now working near perfectly smiley I may at some point go change the filament diameter setting in Cura & test the extrusion length, but I’m now afraid of going away from what I know works well. > [@Dimensional accuracy](https://forum.lulzbot.com/t/dimensional-accuracy/1303/1): > > I’m trying to nail down the dimensions on our printer. A 10x20x30 (mm) block comes out 9.98 x 20.62 x 30.63. Happy with the thickness (better than a quarter of a percent accuracy), but the width and depth are not too close. Now clearly, when designing my own stuff, I can compensate. But if I want to print something like Emmett’s cube gears, all the pins are too big, holes are too small, and AFAICS there aren’t editable files available. Given that, how do I tweak the parameters in Slic3r to … > [@Dimensional accuracy](https://forum.lulzbot.com/t/dimensional-accuracy/1030/4): > > In that case, make the spigot 5.88mm and the hole 12.36mm in your drawing’s dimensions. Depending on how much designing and printing you do, you might be able to save time by printing out a few calibration .stl’s, measuring them, and then creating a table that can be referenced when dimensioning. > [@slightly off x and y axis dimensions](https://forum.lulzbot.com/t/slightly-off-x-and-y-axis-dimensions/176/3): > > You can temporarily set your steps via an M-code temporarily: [http://reprap.org/wiki/G-code#M92:\_Set\_axis\_steps\_per\_unit](http://reprap.org/wiki/G-code#M92:_Set_axis_steps_per_unit) Just because that’s the way it’s always been doesn’t make it right, either. I’ll go ahead and change it on my machine. --- _[View the full topic](https://forum.lulzbot.com/t/steps-unit-right-or-wrong/1830)._