I am not sure how accurate you are trying to be so my thoughts may not be applicable to you.
While your tool length gauge will probably work, I would be worried about how accurate or repeatable it is. I would be willing to bet that it will be easy to be off somewhere between 0.005" and 0.010" unless you are very careful. The way I handled tool changes before I got my BitSetter was to separate each tool as a different file and re-zero Z each time with the correct bit installed.
Hey Nick:
Right now, I’m cutting 2mm G10 board for drone frame plates, so don’t need a lot of depth accuracy. I am aiming for less waste board use and learning techniques.
Part of the use of my gizmo is I have a hard time inserting a bit in the collett, while trying to tighten it up, you know, gravity and all.
Today’s lesson was about tabs.
I conducted my first tool change job today, starting with a 1/16th end mill to drill 3mm holes in some G10 board. The board is 2.035mm thick. Those went well and at the end of that series of tool paths, CM called for a tool change.
I used my tool change seating gauge and once back into the job, the initial 1/8th mill cuts went completely through the board, not leaving any tabs.
Not wanting to have larger pieces of material thrown about later in the job, I paused and re-seated the mill slightly higher in the collet. After that, the job completed.
While the depth gauge helped mount the bits, it’s kinda sketchy with the actual depth as Nick W highlighted the possibility. That or I was really sloppy setting it up to do the bit change. As I mentioned in earlier posts, my primary use right now is cutting board material, so depth isn’t a critical factor until…
Where the tabs came into play. I set all of them to 0.7mm, thinking I had everything under control. When the 1/8th mill ends up making deeper cuts, a thin tab gets cut as well. A tab on the order of 1.5mm would have survived.
Today’s lesson was about how to recover from a power failure.
I’ve been running a 3D printer for a couple of years now and finally realized I needed to protect a print job from a brownout - just in case I’m 8 hours into a 10 hour print, etc. So I buy a UPS, sized for the printer, to handle about 5-6min worth of power loss.
Fast forward to the purchase of the Shapeoko, which I dutifully plugged both the router and machine into the UPS…
About an 2 hours ago, running both printer and router, the shop power cut out for about 5 seconds. Everything stopped of course and I stood there wondering what to do and how to recover.
The print job was completely lost, but I wondered about the router job, which had just started.
I wasn’t the most accurate setting up the zero at the left front of the material, just wanting to get the bit onto the corner of the G10. I ended up giving it a best guess and it didn’t work out that bad with 4 3mm holes slightly oblong, no more than a millimeter off. The rest of the job was downrange of the holes, so it all worked out well enough.
My lesson learned here is I should have tried to be very accurate choosing the zero point, exactly on the corner or possibly placing a mark near the corner - maybe a millimeter in from both sides?, to have something to come back to, just in case.
Does anyone have a better/different technique for resuming a job after a power outage?
I have never had a power outage in the middle of a job but I always set my zero off of a fixed point on the job that doesn’t get machined away. That point could be on my table, mod-vise or some feature on the part. I learned this lesson while dealing with disconnect issues that I have since solved. It is a very good habit to be in.
Looks like you’re making good progress. It’s always a pretty steep learning curve at the start! You’re doing far better than I did when I started 
I have a few tips:
Nick:
First thing is, since my tool changing scheme is kind of a pain, I’m gonna stick with the #112 1/16th end mill for everything for the time being. Cuts the 3mm screw holes great and isn’t that slow going around. Consideration was given to purchase a bitsetter but I figure I can buy a lot of #112s for $120.
I’m using all of the default settings for the #112 bit in aluminum, which is pretty slow. The only thing I increased was the depth of cut from 0.2mm to 0.7mm. That gives me 4 passes for the G10.
Saying that, I can mark a zero point in a material corner or the other thought I had was to simply drill a 16th hole there. No mistaking that zero point.
Stu:
I have some 1/4in MDF I’m using for waste board. It’s a bit flexible though. The tool paths are just about there. For instance, a few things I have assumed were global settings in CC, using the CTRL key to select individual items in a tool path - nope, it’s the SHIFT key. Or select a bit and change the depth of cut, that setting works for all of them - nope. A 17 minute job last night took 55 minutes because I didn’t change the depth of cut for the majority of the work. Fourteen passes per cut at 0.2mm/pass.
I also like the idea of zeroing at the waste board since I haven’t surfaced my cutting area yet. Probably won’t unless I start doing 3D. The setting for that is in the Job Setup, correct?
Writing down the coords BEFORE I zero will get me right back to the start, that’s a great tip. Since I haven’t done it before, I can manually enter those coords, correct, no jogging required?
Thanks, Ron
yes there are quite a few things that I dislike about CC - they are purely personal preference though. I find Vectric Aspire and Fusion 360 work best for me.
Nice to hear you’re pretty well there on toolpaths. I haven’t worked much with G10 so can’t really comment, but there is a lot of value in experimenting with speeds and feeds, you can often push a lot harder than you think, and often achieve a better result
Thats correct, you can select either wasteboard or top or material.
One thing I will say is that I do believe it is worth surfacing your wasteboard, once it’s milled flat you shouldn’t be hitting it, and that will keep it much tidier, and keep your G10 material sitting flat
I can’t recall if CM has that option. I have a feeling it would required jogging to the desired spot then rezeroing. CM is very simple but I personally prefer cnc.js as a sender as it acts a bit more like what I’m used to, and gives you a live view/preview of the toolpath. Many here use it
Morning Stu & Jeff:
Stu, will take a look at cnc.js.
Jeff, I did place a center cross on the wasteboard after my job in the post on 03/14. And a line across the rear Y axis as a limit line for material placement.
The drone frame plates are generally 9-10in across the points of a hexagonal pattern, so consume most of a 12x12in G10 piece. I use the cutting center zero if I do one of those. I did try to offset one job to a material corner to try and save some for battery attachment trays, which I did yesterday when the power failed. I used a left front corner zero for that.
Later this morning, I’ll look at your suggestions, not having looked at the MDI screen in CM yet.
Jeff:
Took a look at the MDI screen and figured I’d screw something up there, so won’t be using that technique.
Afterwards, I drew a point on my tri-rail waste board at the very front left corner of the cutting area, then jogged into it and noted the coords. Then moved off and jogged back in reading off the numbers.
Worked fine, though I need to be aware of using that point’s coords because I would have probably changed bits, so the Z coord will have to set according to that. I would only use this point as a general zero location.
Next test was to setup job material with 1/4in wasteboard. I then drew a point near the left front corner and jogged into it, noting again the coords. Then turned off the machine power and moved the gantry up and back. Powered back up and used the coords to jog back to my zero. I could have also just used the marked point without noting the coords. Best to do both.
I’m satisfied this technique can get me going again with a power outage. Naturally, the power will never interrupt a job again now I have a contingency.
Have a safe weekend.
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