V Bit Carving - Why are the corners not square?

[panf (Felix Pan)]

Hello friends,

Just completed another project. This time I used a 60 degree V bit for the lettering.http://a.co/d/998uDO5
Here it is:

I noticed that I all the corners are always rounded. This appeared in my tests as well. I believe it is because the V bit I am using has a 1 mm tip. Does anyone know how to correct this?I have also tried varying the zero height but it doesn’t correct the issue, It just makes the text more narrow.

Thanks for the input!

[WillAdams (William Adams (Carbide 3D))]

Possibilities:

• uneven stock
• Z-axis zero set too low
• V bit angle incorrect / doesn’t match what was used in CAM

If this appearance matches the preview and you’re using Carbide Create the problem is that the geometry is wider than the V endmill can cut — inset the geometry twice, cut the inner and outer as a V carve, then the middle as a pocket to the depth of the V Carve.

[RichCournoyer (Richard Cournoyer)]

I have (cough cough) had unsquare corners several times, and 100% of the time (for me) it was always caused by having the Z set too deep.

There’s a reason why I set the Z too deep, but that that something we need to get into here…

Remember, wood is seldom flat/parallel, and where you set the Z is not where all the machining in taking place…meaning the thickness if the wood varies…

[neilferreri (Neil Ferreri Ω)]

@panf Try raising your zero to 1mm (exact would be 0.866mm) .above your surface if you’re flat is 1mm in diameter and you’re using a 60 degree bit.
Link to calculator in this post:

V-Bit Feeds and Speeds

Without seeing the Easel project to compare, I’d say the gcode looks fine. My guess is that your v-bit does not come to a true point. That will cause the carves to be wider than calculated at your desired depth. You’ll have to set your Z0 at an offset above the surface of the wood. The offset depends on the width of the flat spot on your bit. With a 60 degree bit, you should be close by offsetting the slightly less than width of the flat. For exact offset, I whipped up a basic spreadsheet …

[panf (Felix Pan)]

Hi all,

I think this bit isn’t appropriate for V carving.
At one angle the bit comes to a point. Turn the bit 90 degrees and it goes to 1 mm. When I raise the Z height to compensate the text gets narrow because not enough material is being milled at the widest point.

I will the 302 bit from carbide3d to compare and reply with the results.
Shipping times may vary. Lol

Thanks all

[Julien]

I remember buying this exact same bit, getting poor results, then getting Carbide3d’s Vbit, and suddenly getting nice Vcarved jobs

[mikep]

Yours is also chipped. I use one of these from time to time, and it’s “ok” at some things (chamfers), awful at others (vcarve is not it’s strong suit). A solid carbide one works better, and they’re pretty easy to get (amazon has the whiteside 1541 for ~$20)