Skew settings

Not sure if this is the right place to ask but here goes.

I've got my machine up and running with reliable homeing and not going past the limit switches, I can make the machine go to all the limits of travel via home written G-code as well as draw circles. I have had a cutter in the machine and did a bit of cutting of a g-code that I found on the net of an Egyptian scene as well a 'm Griffon. While results are not spectacular I had the cutter too deep you can see what they are supposed to be so, so far I'm pleased with the results.

So down to the question, I am getting down to setting the machine up, checking tolerances and what have you so I did a skew test as in the gsuite. After putting the numbers in it came up with a -0.321 deg skew, not bad really as its all made by hand and tape measure. How do I go about getting the skew into the machine so whenever I run the machine I dont have to think about the skew.

Bill

BTW is there a search function on this site, I've looked but I cant see it.

Thanks BigJohn never thought to look on the front page.

I think I'll have to go the software route as I dont have any means to adjust this machine that accurately, aybe the next one

OK I cant type, I put the wrong figures into the gskew programme and got the wrong answer. The correct skew I have is 0.0987deg which I think is not bad for pencil and ruler and sticking bits of wood together. I was doing some searching on the net today regarding skew and I kept getting links to the wiki and millkins.c, which I d/l'd as well as the emc2-dev. I tried to install millkins as per the wiki but it kept saying there was an error and it never made the folder it should have. Info on this module seems to be very scarce and the integrator manual on kinematics just tied my brain in knots and wrung it out. So does anyone know how to use this module or even better how to get to install and then what/how settings to put in to get it to correct the skew.

alastair.d-silva.org/desktop-cnc-milling-machine 5 November update refers to this usbject but again the maths does my brain in.

Bill

Hello,

As John suggested you might try rotating the coordinate system with G10
Perhaps...
Rick G

So am I right in thinking that the g10 and trivkins do the same thing, the only difference is you need to add the g10 to evey g-code programme you run, but the trivkins sets the offset when you start emc.

Andy thanks for the linuxcnc-dev tip I'll try that and see how I get on, if it works then the wiki will need updating.

If the G10 works for you, you could add it to the [RS274NGC] Section of your ini file so it is activated each time you start linuxcnc.
The down side would be if you ran a program that uses G10 rotation it could be changed.

Rick G

So I am right about the g10 skew being specific to the g-code running and it is a volatile setting but the millkins/trivkins settings is applied at start up and is fixed until it is changed in the HAL file.

Regarding millkins I have now got it installed , I was trying the wrong install method, I had to use the one that was just underneath the one I was trying to use. The clues were there I just didnt read them properly.

Yes G10 is a volatile setting, it could however be set to run each time you start linuxcnc. But some g code file may change it, such as a program that uses G10. If no g code changes it during a run it will be persistent the next time you start linuxcnc.
I have never tried to skew with millkins/trivkins settings but if that works for you I would try that avenue.

Might also take a look at John's plasma sheet aligment for ideas.

Rick G