I replaced the eccentric nuts with eccentric spacers and nyloc nuts and (touch wood) nothing has come loose since.
Well, there’s the ShapeOko wiki: http://www.shapeoko.com/wiki/index.php/Calibration_and_Squaring_the_Machine
Not quite as organized or compleat as I’d like. If there’s something you’re looking for or not finding, let me know.
Neal is right about reducing the amount that you take off at each cut. I started a thread to try and encourage people to give an indication of what rates of cut and cut depth per pass they can realistically achieve with the X-Carve.
If people had an indication of this, and kept within those limits, then half the problems that people face would go away. Good expectation management leads to more satisfied customers. Any information gathered would certainly help the Easel development team.
Hey man I had similar frustrating issues a few weeks ago when I set my machine up. The bloke I bought the machine off here in Oz is an absolute champ and helped me identify a few issues that it sounds like you may have. When there are so many variables it can be tricky to work out the one that is affecting you, but I would suggest trying these:
Eccentric nuts are a great idea, but they can be a pain in the arse too. Try loktite on them, because once you have the bolts tight enough, you’re only changing the displacement from center by adjusting the eccentric nuts, not the tension. This should stop them loosening. If still an issues try eccentric spacers and normal nylon nuts.
Increase airflow to your stepper drivers. The drivers dropping out in thermal overload would appear the same as missed steps. Easy to snap a bit if the z-axis thinks it is somewhere it isn’t because it shut off for a bit. This sounds like the problem here:
going great until about 72% and it started carving into the design like it skipped a bit of a step
Less depth, and higher feed rate is your friend. It spreads the load between your spindle’s torque, and that of the motors/drivers.
I think that it would help a lot of people to get Chipload explained as well as the other nuances of the depth=half diameter rule of thumb.
I am working on a video about this right now. It will be relevant to the hand held router user, the table router user and the CNC user.
In this video I will devise a specific test for X-Carve rigidity in the X-Y plane which will help users identify the maximum feed rate and step down/over for their particular machine. This will make the test independent of the modifications and even build quality of the specific machine. I am still thinking about the Z direction and may leave this to a later date.
My aim is to help people reduce their disappointments and increase their enjoyment and productivity.
I may have to enlist some additional help from forum members or the folks at Inventables.
I will repeat this post on the other thread for completeness.
@KeddyKleinbergs One thing I did to eliminate the need to adjust the eccentric nuts was to replace the eccentric nuts with eccentric washers and use nylock nuts to hold things in place. I have not had to adjust the v-wheels since then (a few months) just like @GeoffSteer mentioned above.
Just for the sake of helping @KeddyKleinbergs and others who may be having issues with this, @ErikJenkins and @GeoffSteer where did you guys find the eccentric spacers? Available at a local hardware store?
“knocks on wood” I haven’t had to mess with pots, V-wheels, or even zip tie belts, and I do aluminum, PVC, Wood, you name it. But now that I’ve said this I’m sure the time will come in the very near future!
Just so you know you’re not alone, here’s my post with similar frustrations of getting the machine dialed in best.
@RobertA_Rieke 's videos on belt tension and pot adjustment have been the biggest help so far. I still can’t do 2stage cuts perfect and have some alignment issues on each cut.
The snapped bit was my fault this time. I was doing a two-stage carve and since I’d have a problem with an axis shifting during the bit change I thought hmmmm… I probably shouldn’t torque the collet as hard as I have been. Well, appaerent I didn’t torque it enough because was i took the collet off to get the broken bit out I could see it had moved in the collet substantially. To tell you the truth, I was sure I was tight enough without being excessively torque… apparently I was wrong! Lesson learned!
That being said, I do watch my settings on depth and feedrate, although I have been known to tweak them from time to time to lessen the cut time , nothing too agressive though! I’ve read in the Forum quite a bit that the presets in Easel are a bit restrained. But, I will only increase feed by maybe a couple inches per minute. It would be very nice if the presets in Easel were a bit more comprehensive, there isn’t much for softer woods (like pine, cedar and poplar), so I’ve had to go online, find the Janka hardness and match it to the closest preset material and tweak from there. Right now with pine I think I’m going with a .025 depth, 36 inches per minute with a 12,000 RPM on the spindle. Is that pretty close to correct?
I have been tweaking my machine as part of the video that I am making and the eccentric nuts are driving me…nuts ! I found the problem comes when one does the final tighten after adjusting. Despite holding a spanner on the eccentric nut it always seems to go off a tiny bit.
Where can these be bought?
Get info that helped me with feeds and speeds. Jump over and read the rest of the thread
I got my eccentric washers from invetables and the nylock nuts from amazon:
the eccentric nuts on the v-wheels are definitely what I seem to be having the most issue with, especially on the x-axis. In my opinion, Inventabless design doesn’t allow to get everything as tight as it should be for no slippage. To properly torque a bolt and nut assembly you should be spinning the nut, not the bolt and you just can’tdo that with an eccentric nut. Because of the angle you must bring your hex key in the access the button head bolts in the x-axis, again, you can’t get enough torque on the bolt to tighten it down for fear you’ll strip the head, even with a ball end. I have done the blue Lock-Tite on everything to no avail, They always seem to actually tighten on me over time, although some have loosened also, to the point the extrusion is somewhat pinched and the movement of the carriage isn’t smooth. So, I am liking the idea of the eccentric spacer or washer with a Nyloc to lock it in position.
@RichardShannon has a nice mod he did to tie the opposite v-wheels together and I’m really liking the idea, X carriage stiffening mod so I’ll be getting on this upgrade when I get my eccentric spacers.
Which eccentric spacers did you guys used exactly, was it the standard ones or low profile ones, I just found a couple last night that were lose and obviously thats not gonna stop. So Im going that route with the spacers and hopefully that would stop or at least make them stay tight longer. Thanks in advance.
I used the standard sized ones, but I will get some low profile ones to replace the z-axis eccentric nuts as there is less room to work on those.
Thank you Erikjenkins for the quick reply!
Got my eccentric spacers order from here and threaded standoffs from McMaster… I’ll wait on the socket cap screws, I have a nut and bolt house down the road from me. Convenient, huh?!
I have found a website that has an online app called G Wizard the Machinists Calculator you can download and use it free for a month, the Annual price is like 79 US dollars.
I have “tuned” it to my machine and it seems to give decent calculations
I wonder if we asked Inventables nicely, if they could try and get a hobby price like 5-10 US dollars per annum?
79 dollars is just too much money for me
The nice thing about G-Wizard is that one only needs to purchase a single year’s subscription if using a hobby-level machine — this will grant one a perpetual license for using the software at 1HP.