V-carve issue. A newbie needs some help :)

Newbie says:
I wanted to cut something small on a wood but the vector graphic had two lines on the edges. I couldn’t choose only one line because these lines were in group. In inkscape this vector file had only one line but whenever i was trying to import the .svg file in carbide create u could see two lines and not one. In order to cut it properly i had to cut between the two lines so i used the V-carve option in toolpaths. As far as i know, carbide create doesn’t have an eraser so i couldn’t erase one of these two lines. The graphic i used was a ready .png and i converted it to .svg, then import it to carbide create.
If you create a v-carve toolpath, you need to use a v-groove bit. I wanted just to cut between the two lines all the way down so i was just cheating it and i used a 2mm endmill with .250 shank. Where it says stepover i wrote 0.350. My stock was 6mm so i wrote 6.2 in depth per pass because i needed to make sure that it will cut it all the way down (i used a wasteboard under my stock).
When i run the gcode, shapeoko 3 was cutting only about 2.5mm. I tried it several times and still the same. I even tried to change the depth per pass to 8 or even 12 mm and still it was cutting less than half of 6.2mm. I was waiting for it to finish and then i was trying again. Over and over again. Tried to reset carbide motion, tried to make again the gcode from scratch and the problem persisted.
I’m i missing something? Anyone knows why i was experiencing this issue?

I’m really newbie btw. I know nothing about cnc and I’m trying to learn…I come across several problems/issues/questions everyday since the day i decided to deal with cnc. But I’m learning everyday! At least i managed to build the machine and do my first projects, with a lot of effort though because i have too many disconnect issues(waiting for the new board to arrive). But to be honest, i loved it. I can create so many things!

I will appreciate it if someone helps me. Thanks.
Sorry for any grammar mistakes. Still trying to learn and the english language properly. :wink:

It sounds as if you want to:

  • draw the path which you want cut
  • declare it as a profile cut in the CAM step in Carbide Create

There is a nascent page on it: http://www.shapeoko.com/wiki/index.php/Carbide_Create and you may find some of the links there of assistance.

@WillAdams Basically my question is simple and i can’t find an answer in the specific link.
I made a v-carve toolpath to cut my shape as deep as my stock was and i used an end mill so it can cut it nicely. But instead, the machine was cutting less than the depth i put in v-carve. My stock’s depth was 6mm and i put 6.2mm. The outcome cut was about 2.5mm depth. I tried everything, even changing the depth from 6.2mm to 8 or 10mm. Still the same, only about 2.5mm cut.


Thanks for your reply.

AIUI, a V- carve tool path will be limited in its depth by the width of the area which is being cut.

If you want to cut to a specific depth, cut to that depth using the control afforded by a profile path or a pocket.

1 Like

Now i get it. Thanks a lot for your explanation and your reply.

I’m still confused by the V-Carve setting in Carbide Create. I am using a Rockler V-carve bit that is 60 degrees 1/2". When I set up the tool in the tool library, do I set the diameter as .5" even though that is only the diameter at the widest part (i.e. plunged all the way in? the diameter at the very tip is tiny). I’ve tried setting it from 1/32" all the way to 1", trying to get it to cut deeper than .1", but the depth per pass doesn’t seem to be based on the size of the outside shape its cutting. I’d like to cut letters that are 1/4" deep for example, but I can’t figure out what I need to change to the font or tool settings to make that happen. The only way I can get close to that depth is to use the Contour cut, but that doesn’t make a single pass the way V-carving does. Any help would be greatly appreciated.

If you wanted to cut 1/4" deep w/ a V-carving, then you’d need to cut a feature sufficiently wide, using a V-but w/ a sufficiently acute angle as to reach that deep.

Entering the width of a V-but is likely done in the event the cut will need to be over-lapped.

Excel formula for calculating width / depth
=TAN(RADIANS(B3)) * B4 * 2

Thanks, Will! So to make a deeper cut given the same width of the letters, I have to tell Carbide3D that the V-bit is a sharper angle. I just tried this with 30 and 45 degrees and it does indeed work. I’m assuming that V-cuts are always single pass, so the depth per pass is a way to limit the depth to be no deeper than the stated amount, but they may end up significantly shallower if the shape of the enclosing object the tool path is approximating is too narrow to support the depth.

That said, it’s a bit counter-intuitive. If I want to make a sign by hand, I just plunge in the V-bit as deep as I want and start drawing the letters. So I’d like to be able to say “draw a V that is .25” deep" and understand that the angle of the bit will determine how thick the letters appear. But in Carbide Create, if I want a letter that is .25" deep, I need to make sure the font is incredibly large.

By the way, I clicked on the link and I don’t see what the Excel cells B3 and B4 contain. I’m guessing B3 is the angle of the bit and B4 is the width at the widest point? Or the length of the flutes?

Footnote link is to: Shapeoko CNC Router, Rigid, Accurate, Reliable, and Affordable which notes:

Where B3 is the angle in degrees and B4 is the depth in inches

Thanks! I was hoping I could just write some text in Carbide Create and indicate that I want it to cut 1/4" deep, since that’s the way I’d think about it if I was routing by hand, but I think I can achieve the same effect either by finding fonts that are large enough to support the depth I want or exaggerating how acute the angle of the bit is.
So is the depth per pass used in v-carving? i.e. If the width requires a cut that is 1/4" deep but the depth per pass is only 1/8", will that cause it to make two passes? Or will that cause the text to be shallower and smaller because it limits the maximum depth?

V-carving is more akin to traditional letter-carving w/ chisels than routing. See Shapeoko CNC Router, Rigid, Accurate, Reliable, and Affordable which lists:

Creative Lettering Today by Michael Harvey — Republication of several classic works, Calligraphy in the Graphic Arts, Creative Lettering and Carving Letters in Stone & Wood with additional new information on digital letterforms. The computer information is specific to the Macintosh program FontStudio (no longer available), with occasional references to Fontographer, but includes mentionings of concepts simply not addressed anywhere else.

Im trying to add an Amana Tool 60° V, RC-1148. Ive reviewed the bit specs on their site and it seems like I have them correct. Does anyone know what i may have wrong here?

Type: Vee
Descrip: 60° V
Tool #: rc1148
Diameter: 1.062”
Flute length: 1.062”
Angle: 30°
Num of flutes: 1

I also noticed that this bit, compared to the default 60° V in CC, has much different depth per pass, spindle speed, feed rate and plunge rate. Is that accurate? That may be nothing to worry about as i know the bits arent exactly alike, although they are are both 60v’s.

I believe the difference is caused by the greater diameter and flute length and # of flutes which seem to be taken into account.

I would suggest using the suggested numbers as a starting point and test in a piece of scrap using the technique from: https://precisebits.com/tutorials/calibrating_feeds_n_speeds.htm

Awesome, thank you Will.
I’m new to CNC, so the variations in feeds/speeds is something I’ll have to grasp a little at a time.