Things you wished you knew

Hey guys. For those of us about to build our Longmill what are the top things you wished you knew before you built your CNC?

@Chyren Most of my build went very well. I had the “old” instructions and no videos. :wink:

A couple of things:

  1. I wish that I had known to clean the paint out of the holes on the gantry plates where the eccentric nuts fit. (In fairness to Chris, this may have been mentioned in the instructions. But, I’m a guy. I don’t need no steenkin’ instructions. :grinning: ) I found the wheels difficult to adjust until I cleaned out the holes a bit so that the nuts turned more freely.

  2. I wish that I had been more aware of the problems associated with the static caused by dust collection and its effect on the Mill, grbl and UGS. I had too many freezes that I eventually resolved by grounding my dust collection piping. Before I figured that out, I messed up some nice jobs.

  3. I wish that I had known to go to the Google UGS group earlier than I did. UGS is a work in progress. Since moving to a recent version, all my problems with it have disappeared. It still has its shortcomings, but that can be said of all the code senders. On the Google group, there are great guys to help out.

  4. Finally, I wish that I had known that the router must be turned on BEFORE hitting the Send button. Chris doesn’t mention this anywhere in the instructions, and I can attest to the fact that the Mill is strong enough to plow through foam with a 1/8" bit in an OFF router. It can also move a piece of MDF that is well clamped by pushing it with a 1/4" bit in an OFF router. :grinning: :grinning:

One thing that I can say is that I am glad that I did know enough to reach out to the people here for help. This forum and our hosts are a fantastic resource.

Have fun, Gary


Hear, Hear! Excellent commentary G.

I second Grant’s comments and will add a few of my own.

I know this falls under general shop safety 101 but I’m amazed how many people don’t engage in basic safety practices, or at least don’t consistently.

  1. Eye protection is a must. The machine moves fast and spins fast and it can throw things in a split second. You will hit screws. You will forget to put tabs, tabs will break and other pieces of debris may get launched at you or someone else. Eye protection. Eyes aren’t easy to replace. Make sure it has the appropriate ANSI rating. I have a pair of Beretta shooting glasses as well as a newer pair of Milwaukee ones that I quite like.

  2. Hearing protection. This is the one that I see so many people dismiss. I used to dismiss it too. Hearing loss is non-reversible. Period. It happens very slowly (at first) and almost isn’t detectable but as you age you’ll really start to notice it. The router isn’t as bad as the shop vac, in my experience. When cutting, the two combined can make quite a racket. Good quality (I like 3M) ear defenders with a high db rating should always be used. I actually use them with my drill and driver as well. The impact driver in particular, especially when screwing down in to the MDF wasteboard, can make quite a loud sound and you’re very close to it. You’ll thank me when you’re 60. :slight_smile:

  3. Respirator. I have to admit I’ve been a bit lax on this the past few weeks but I’ve mostly been tinkering with the machine itself and not cutting much. MDF is full of crap you don’t want in your lungs. Plywood is also full of glue and other nasty things. Cedar dust is straight up bad for you. Any material amount of cutting means wearing a respirator and having both a shop vac for extraction as well as some kind of air filtration for the fine stuff you can’t see. Again, I really like 3M here. I got mine initially at a Sherwin Williams paint store. It’s a P100, cartidge based type recommended by a buddy who is in professional site safety.

  4. In the combination useful/safety category - I am loving my proximity sensor/end stops. They’ve already saved me multiple times where I forgot to zero my XYZ or I forgot to update an XYZ point in the CAD files or I simply fat-fingered a value and told UGS to fire my machine off to coordinates far past the end of the table. Likewise, I’ve avoided some dangerous accidental cuts and avoided damaging nice stock because the sensors cut in and saved me. That, and being able to home the machine to an identical known position each time I power it on make them, to me, essential to regular work on the machine - especially if you are going to be doing multiple bit changes or have to interupt a job and leave it over night to restart it later.