[Stair19]

Hi-
This is my first post ever on CNC Zone or any forum concerning CNC. I am totally new to CNC although I have been a woodworker for 25 years. If I am posting in the wrong place please let me know. Utilizing Visual Mill, I will be v-carving 3/4" tall lettering in hard maple on my CNC. Can anyone recommend a ballpark spindle speed and feed rate? I am using a CMT 858.501.11 60° Laser Point Bit, 1/2-Inch Diameter, 1/2-Inch Shank router bit. Thanks

[forhire]

Can anyone recommend a ballpark spindle speed and feed rate? I am using a CMT 858.501.11 60° Laser Point Bit, 1/2-Inch Diameter, 1/2-Inch Shank router bit. Thanks

This cutter has a maximum depth of cut of 7/16" so it will have to be done in multiple passes. One of the reviewers on Amazon states that he's carving at 15k rpm and between 40-60ipm feeds, this sounds like a good conservative starting point. Being carbide at 15k I'd expect around 200 ipm to really get the production if your machine has the HP. You might read through some of the comments because there were a few other interesting ones, including one that claims the angle was 58 degrees not 60. I'd recommend programming some practice lines and try different feeds and speeds and compare your finish appearance and make sure your fast enough to not burn but not so fast that the machine struggles. Listen to the spindle and adjust to find your sweet spot.

You can use the feed and speed calculator in Visualmill to get you close. This calculator assumes fairly ideal conditions so you may need to adjust accordingly. I also use GWizard to calculate feeds and speeds. It's nice because it can take into account tool deflection, which is especially nice when setting up small tools or long tools. It also shows a HP estimation which can help keep you within the range of your machine.

You might look at the tables in this manual. It has some starting values for v-carving.
http://www.shopbottools.com/files/SB...%2011%2003.pdf
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[dansutula]

Stair19,
In addition to the advice provided by "forhire", I would like to point out that "in theory" the speed (surface feet per minute) at the tip of the V-cutter tool is approximately zero, regardless of the spindle RPM's. For this reason you may want to start by roughing out as much material as possible with a ball end mill or flat end mill.
Good Luck!
Dan