# Using the Longmill as a sanding robot **URL:** \ **Category:** 📛 Others\ **Created:** [December 20, 2021, 3:07pm UTC](https://forum.sienci.com/t/using-the-longmill-as-a-sanding-robot/4630 "2021-12-20T15:07:13Z")\ **Posts on this page:** 11\ **Page:** 1
**Author:** ![mid\_al](https://forum.sienci.com/letter_avatar_proxy/v4/letter/m/cab0a1/32.png) [@mid\_al](https://forum.sienci.com/u/mid_al)\ **Post date:** [December 20, 2021, 3:07pm UTC](https://forum.sienci.com/t/using-the-longmill-as-a-sanding-robot/4630/1 "2021-12-20T15:07:13Z")
I can’t currently afford a drum sander so I’m trying to get creative with time management. Has anyone tried using the Longmill with a random orbit sander to make a sanding robot? The software side is easy, a surfacing program with a 5" bit set to slow speed. I have some ideas for a mounting bracket including some that I have come across online, but was looking for some neutral input from this community. Thoughts? ---
**Author:** ![gwilki](https://forum.sienci.com/user_avatar/forum.sienci.com/gwilki/32/366_2.png) [@gwilki](https://forum.sienci.com/u/gwilki)\ **Post date:** [December 20, 2021, 4:43pm UTC](https://forum.sienci.com/t/using-the-longmill-as-a-sanding-robot/4630/2 "2021-12-20T16:43:23Z")
@mid_al Welcome back, Michael. Without getting into whether this is a good idea, if you have not seem this video, it may give you some thoughts. Good luck. [https://www.youtube.com/watch?v=et0BiANn-ns](https://www.youtube.com/watch?v=et0BiANn-ns) ---
**Author:** ![mid\_al](https://forum.sienci.com/letter_avatar_proxy/v4/letter/m/cab0a1/32.png) [@mid\_al](https://forum.sienci.com/u/mid_al)\ **Post date:** [December 20, 2021, 5:57pm UTC](https://forum.sienci.com/t/using-the-longmill-as-a-sanding-robot/4630/3 "2021-12-20T17:57:09Z")
Thanks! I have seen that video and am designing something similar. The part that is stumping me is how to attach it to the z axis sub-assembly. ---
**Author:** ![gwilki](https://forum.sienci.com/user_avatar/forum.sienci.com/gwilki/32/366_2.png) [@gwilki](https://forum.sienci.com/u/gwilki)\ **Post date:** [December 20, 2021, 6:36pm UTC](https://forum.sienci.com/t/using-the-longmill-as-a-sanding-robot/4630/4 "2021-12-20T18:36:11Z")
@mid_al You could consider attaching it to the router mount. Remove the front piece of the router mount, and use the 2 x 5mm holes in the mount to hold your new bracket. **PLEASE note, I am not recommending this**. I have no idea of the forces you will be applying to the router mount and how they could affect the linear guides of the Z axis or any of the other moving parts. I merely throw it out there for consideration. I prefer to do my orbital sanding by hand. 😀 ---
**Author:** ![NeilFerreri](https://forum.sienci.com/user_avatar/forum.sienci.com/neilferreri/32/1959_2.png) [@NeilFerreri](https://forum.sienci.com/u/NeilFerreri)\ **Post date:** [December 20, 2021, 6:40pm UTC](https://forum.sienci.com/t/using-the-longmill-as-a-sanding-robot/4630/5 "2021-12-20T18:40:50Z")
What about just using a sanding disc in the router? > **[3 Inch (75mm) Hook and Loop Sanding Pad for Sanding Discs with 6mm Dia Shank...](https://www.amazon.com/Sanding-Discs-Shank-Attachment-Buffering/dp/B0748BC3RP)** > > 3 Inch (75mm) Hook and Loop Sanding Pad for Sanding Discs with 6mm Dia Shank Drill Attachment + Soft Foam Layer Buffering Pad, 3 Pack: Amazon.com: Industrial & Scientific ---
**Author:** ![Erik](https://forum.sienci.com/letter_avatar_proxy/v4/letter/e/b5ac83/32.png) [@Erik](https://forum.sienci.com/u/Erik)\ **Post date:** [December 21, 2021, 5:39pm UTC](https://forum.sienci.com/t/using-the-longmill-as-a-sanding-robot/4630/6 "2021-12-21T17:39:04Z")
WOW awesome simple idea, Smack!!!" (slapping forehead) ---
**Author:** ![mid\_al](https://forum.sienci.com/letter_avatar_proxy/v4/letter/m/cab0a1/32.png) [@mid\_al](https://forum.sienci.com/u/mid_al)\ **Post date:** [December 22, 2021, 12:07am UTC](https://forum.sienci.com/t/using-the-longmill-as-a-sanding-robot/4630/7 "2021-12-22T00:07:41Z")
I had considered this, but was worried about swirl marks. I had tried something similar using dremel bits to clean up bowls, but it had its problems. Mostly, there was no give in the bit. I broke one and scratched several test peices. The metal rod would poke through. I am almost finished my prototype. I’ll upload some video tomorrow once I finish it. ---
**Author:** ![mid\_al](https://forum.sienci.com/letter_avatar_proxy/v4/letter/m/cab0a1/32.png) [@mid\_al](https://forum.sienci.com/u/mid_al)\ **Post date:** [December 22, 2021, 12:11am UTC](https://forum.sienci.com/t/using-the-longmill-as-a-sanding-robot/4630/8 "2021-12-22T00:11:10Z")
![Screenshot_20211221-190901_Chrome](https://forum.sienci.com/uploads/default/original/2X/0/00cd4cef0dfb344490abf861c76c5c8acaa1a0a4.jpeg) Here is part of the jig. I also have four 4" shock absorbers and two small brackets to attach the shocks to the router cradle on the z. ---
**Author:** ![mid\_al](https://forum.sienci.com/letter_avatar_proxy/v4/letter/m/cab0a1/32.png) [@mid\_al](https://forum.sienci.com/u/mid_al)\ **Post date:** [December 22, 2021, 11:27pm UTC](https://forum.sienci.com/t/using-the-longmill-as-a-sanding-robot/4630/9 "2021-12-22T23:27:27Z")
It works! [![](https://img.youtube.com/vi/HHsZ5BGAIvY/maxresdefault.jpg "Using a Longmill CNC as a sanding robot") ](https://www.youtube.com/watch?v=HHsZ5BGAIvY) ---
**Author:** ![Scottinharwood](https://forum.sienci.com/letter_avatar_proxy/v4/letter/s/8edcca/32.png) [@Scottinharwood](https://forum.sienci.com/u/Scottinharwood)\ **Post date:** [December 24, 2021, 12:47am UTC](https://forum.sienci.com/t/using-the-longmill-as-a-sanding-robot/4630/10 "2021-12-24T00:47:09Z")
Interesting. I am also an amatuer astrronomer and have never ground my own mirror but have considered trying one of the home built automated mirror grimders. If I could use this idea to do the rough spherical grinding on the longmill, and maybe the initial parbola formation, could reduce the time of hand grinding…hmmmmm. ---
**Author:** ![FBWoodcraft](https://forum.sienci.com/user_avatar/forum.sienci.com/fbwoodcraft/32/6411_2.png) [@FBWoodcraft](https://forum.sienci.com/u/FBWoodcraft)\ **Post date:** [January 1, 2022, 2:28am UTC](https://forum.sienci.com/t/using-the-longmill-as-a-sanding-robot/4630/11 "2022-01-01T02:28:07Z")
I used the 2 inch sanding disc, it worked great. Haven’t figured out how to send attachments on reply’s or I’d send the video I took of it. I ran a 3 surfacing tool path with different angle’s each with only a 0.005" cut depth with 3 passes. It worked really good until the very last pass and GSender had one of it’s random ‘Hard Stop Error’s’ and stopped moving, left a burn mark before I could shut it down. I used it on raised panel cabinet doors. I still used my orbital sander for the finish work, which you’d want to do even with a drum sander for the finer grit sanding.