# TLS for AltMill **URL:** \ **Category:** 🧰 CNC Setup\ **Created:** [April 7, 2026, 8:22pm UTC](https://forum.sienci.com/t/tls-for-altmill/26123 "2026-04-07T20:22:01Z")\ **Posts on this page:** 2\ **Page:** 1
**Author:** ![\_benr](https://forum.sienci.com/user_avatar/forum.sienci.com/_benr/32/11954_2.png) [@\_benr](https://forum.sienci.com/u/_benr)\ **Post date:** [April 7, 2026, 8:22pm UTC](https://forum.sienci.com/t/tls-for-altmill/26123/1 "2026-04-07T20:22:02Z")
I have an AltMill on order. My first CNC. While I know there’s a lot to learn, I hope to figure it out swiftly once the machine is in hand. One thing I’ve noticed in use on other manufacturers’ CNC machines is a “bit setter” or “tool length sensor” to efficiently reset Z after tool changes during a carve. Sienci don’t offer a first-party product yet, though I believe they intend to in the future. My understanding is it’s intended to be used alongside something like the AutoZero Touch Plate (touch plate for initial all-axis zeroing, and then TLS for Z-only zeroing during the carve). It appears the SLB-EXT board has a 3-pin connector for a TLS. This model [https://topcom.cz/products/digz/digzfix/](https://topcom.cz/products/digz/digzfix/) seems like a good option: low profile, 3-wire, “NC” (normally closed), and designed for permanent mounting. Does anyone have thoughts on the use, or usefulness of a TLS like this? Or on this specific model for the AltMill (2x4 in my case)? Or on the best mounting position on the AltMill for the TLS? ---
**Author:** ![Chucky\_ott](https://forum.sienci.com/user_avatar/forum.sienci.com/chucky_ott/32/8692_2.png) [@Chucky\_ott](https://forum.sienci.com/u/Chucky_ott)\ **Post date:** [April 7, 2026, 9:08pm UTC](https://forum.sienci.com/t/tls-for-altmill/26123/2 "2026-04-07T21:08:56Z")
@_benr Welcome to the forum and hope you have fun with your Altmill. I can’t answer your question on the TLS, but if you’re not using an ATC, then the AZTP (auto zero touch plate) is more than capable for zeroing z only.