Hello Anne, and welcome to the Cafe forum and engraving.
from the sound of things your problem is the lift or belly angle of your gravers.
The front angle should be about 45-50 degrees.
And the bottom or belly should have a small and short relief cut of about 15 degrees.
On your #41 HS round graver you can hold it by hand at about 15 degrees on a stone to create a short grind of about .010 that follows the front edge.
Your #41 carbide graver can have the same treatment using diamond stone or lap.
This little relief cut will help in stopping your gravers from diving.
Of course Anne, that depends a lot on the metal you are cutting and how deep you are going.
A round graver usually requires more pressure than a diamond/square graver because of the larger frontal area in the metal.
Only time and practice will give you the answer for push or hammer engraving
If you are push graving remember to turn your metal into the graver.
If you don't have a ball vise holding your metal then mount the metal on to a piece of wood.
Hi Anne, I remembered a work I did some years ago analyzing the area of some burins shapes involved in the act of cutting at different depths and though that it might be interesting for you to see. Of course, the bigger the area the more force required.
Also, as you are interested in wood carving, I would like to suggest you to take a look at the post of our friend and Cafe member Evgeni Dimov, his work is beautiful and awesome! His user name here in the Cafe is dimovengraving.
Leonardo, it's wonderful having you back on the forum.
Only you with your analytical mind and engineering experience could provide the wonderful graph of pressure for different graver shapes and depth.
Great info for someone who is developing a cutting system.
Thank you for all your work on this and sharing it with us.