Predicting speed and power V.s. hardwood hardness

I have been wondering how best to set power and speed for engraves and cuts/ scores and the only way seems to be to keep labourious records of settings and continuous experimentation. Is there a way to predict what the settings should be for a given material? I started with the assumption that hardness should directly affect settings and took a peek at the ProofGrade settings for hardwoods, since hardness info is readily available via

What I found was a somewhat linear correlation between power and hardness and a reasonably strong correlation between speed and hardness. Essentially- Cut speed (At full power) decreases with increasing hardness and power increases with increasing hardness. Logical so far?

Now here are some reasons why these findings may NOT actually hold IRL-

  1. I only looked at the 6 hardwood PG materials from GF (Maple, Cherry, Poplar, Walnut, Red Oak, Basswood)
  2. I have no idea what variety of hardwood GF is using. For example, Walnut has 9 different varieties with hardness on the Janka scale ranging from 910 to 1670). For the plot, I used the median hardness that may not represent the actual hardwood variety GF uses
  3. Hardness itself may be irrelevant to determining power/ speed settings. Perhaps it is moisture content or density or rupture strength or…
  4. GF itself may not be factoring in material characteristics when determining settings- They may be doing this based on trial and error and the settings will work ONLY on that variety/ batch of hardwood. There may be NO correlation to be had at all

Only scratching the surface- I imagine this might be like what the earliest book publishers went thru when the printing press revolution started- We have come to expect a level of standardization in our letter paper that has taken a long time evolving :slight_smile:


Very interesting research. I like the way you think! Much more work and we will expect a paper from you.


Really great work!

This is really great! Thank you for sharing! Have you tried any other woods since you posted? I am wanting to engrave a Sheesham cutting board tomorrow. Janka hardness is 1660!