# Adding an Openbuilds Openrail Y axis to a Taz 3/4/5 **URL:** \ **Category:** Hardware\ **Created:** [July 19, 2015, 11:59pm UTC](https://forum.lulzbot.com/t/adding-an-openbuilds-openrail-y-axis-to-a-taz-3-4-5/2019 "2015-07-19T23:59:04Z")\ **Posts on this page:** 1\ **Showing post:** 45
**Author:** ![special-k](https://sea2.discourse-cdn.com/flex020/user_avatar/forum.lulzbot.com/special-k/32/59_2.png) [@special-k](https://forum.lulzbot.com/u/special-k)\ **Post date:** [January 9, 2016, 4:44am UTC](https://forum.lulzbot.com/t/adding-an-openbuilds-openrail-y-axis-to-a-taz-3-4-5/2019/45 "2016-01-09T04:44:07Z")
> [@piercet](#): > > Huh. That’s definitely odd about the extra 5mm. Good to know for future people that may build these though, I’ll add it to the notes. > > I’m working on an updated X backplate for the printed backplate version. The milled backplate is fine as is if you went that route. The printed one that exists right now is a bit too thick. > > Are you going to use the standard Z endstop target, or the Micrometer based one? I don’t have the exact part number for the micrometer listed anywhere, but I can find it if you want it. It does seem to help keep the level exactly where I want it I have been studying your pictures and posted micrometer head measurements trying to suss out which one it might be. From the pictures, it looks like it might be an Insize 6372 series, but that’s a pure guess. From the dimensions you listed in [post 15709](https://forum.lulzbot.com/t/adding-openrail-z-axis-to-a-lulzbot-taz-4-5/2108/17), it looks like a [Starrett 463MP](http://www.starrett.com/metrology/product-detail/Micrometer-Heads/Micrometers/Precision-Hand-Tools/Precision-Measuring-Tools/463mp#Features) might work, but their schematics don’t mention a retaining ring or mounting base. --- _[View the full topic](https://forum.lulzbot.com/t/adding-an-openbuilds-openrail-y-axis-to-a-taz-3-4-5/2019)._