Engraving concave areas

Joined
Feb 20, 2022
Messages
74
Howdy engravers

I’m a seasoned metal worker and commercial artist but less than a year into learning pneumatic engraving and traditional vocabularies. I’d love to hear how you all approach cutting concave areas.


I’m not really any good but I’m gaining confidence turning convex (round) items into my graver with a ball vice. A little planning (cheating!) helps too and often flows better anyway by having more lines go down a gun barrel or cylinder than around it- but scrolls gotta curl.

So now I’m confronted by my first project that has major concave area- not an interior corner, but a large long shallow dish. It’s a Bond Arms derringer. It isn’t like doing the inside of a spoon but it’s intimidating.

I’m thinking the corner is pronounced enough that I can get away with separating panels above and below it in the design and avoid the issue but I want to make some concave practice plates after and start adding this skill to my toolbox.

I’ve seen graver adapter holders that angle the graver off your handpiece so you hold a higher working angle with the same heel geometry to get your handpiece up out of the way, and I can probably bend & re-harden/temper non carbide gravers then sharpen by eye.

Here’s my sheet of templates and version 1 of the design for the barrel. It might get fine tuned or possibly totally changed depending on how I do with the rest of the gun making a coherent feel. You can see the trouble spot on the gun, and also the yellow layout lines for how I might lay out the complex areas on the receiver. I’m definitely working more at repeat modules so far on this design, and less with loose flowing elements, but that could change- I could end up drawing english small scroll or art nouveau ribbons before I’m happy and start cutting!

I wouldn’t mind advice specific to the problems offered by this specific canvas, but I’m looking more for discussion of how y’all deal (or don’t deal) with convex areas.

Thanks!
Kevin Cunningham
B468661E-4726-423E-BC71-2DC8BC325E89.jpeg
 

mitch

~ Elite 1000 Member ~
Joined
Jul 23, 2007
Messages
2,635
Really steep, 30-35deg, heels, with a correspondingly shallow face to maintain a more or less consistent point geometry. Grind and polish a radius on the belly line of the graver so it doesn’t scratch if it contacts an adjacent surface.
 
Joined
Feb 20, 2022
Messages
74
Really steep, 30-35deg, heels, with a correspondingly shallow face to maintain a more or less consistent point geometry. Grind and polish a radius on the belly line of the graver so it doesn’t scratch if it contacts an adjacent surface.
Mitch

That’s a simple elegant solution- keep the handpiece and graver the same and orient the cutting geometry to provide tool & hand relief.

Thanks so much for sensible concise feedback!
Kevin
 

monk

Moderator
Staff member
::::Pledge Member::::
Joined
Feb 11, 2007
Messages
10,857
Location
washington, pa
one can also bend the graver shaft into an appropriate curve. get some pipe elbows or a few junk spoons and practice till u r comfy with doing concavities
 

mitch

~ Elite 1000 Member ~
Joined
Jul 23, 2007
Messages
2,635
Mitch

That’s a simple elegant solution- keep the handpiece and graver the same and orient the cutting geometry to provide tool & hand relief.

Thanks so much for sensible concise feedback!
Kevin
You’re welcome. Obviously it will feel a little weird to use at first with such a steep angle of attack, but you get used to it.
 
Top