I agree, some of the brass alloys are very difficult to get a clean cut on.
Some alloys don't cut well at all, they feel almost gritty and crumble in front of the point instead of cutting cleanly. It's a battle to keep an even line on some because of the alloy.
Cutting brass, copper, silver gold, etc ,,you can use a sharper face angle on the graver than you would normally use on steel. The strength of the steel cutting tool isn't needed and a sharper angle shears the softer alloys cleaner than a blunter one.
Try a graver lube on the alloys as the metal can be 'sticky' on the graver,,,brass, copper, silver, gold ect can rub off onto steel easily and build up on the sharpened edge giving a less than perfect cut.
There are specific lubes sold for the purpose through engraving supply houses but an all purpose lube is kerosene. Some say the sented lamp oil used in the decorative table and patio lanterns works well too.
I put a couple of drops into a cotton ball that is placed inside of softdrink bottle cap. You don't want anything more than a micro coating on the tip of the graver. Touch the graver into the cotton ball and go to work,,re-newing it occasionally as needed.
Also on brass, silver, etc, put a highly polished heel (and face)on the graver and don't be shy about polishing the heel into place with a gentle sweep to it instead of a flat.
That highly polished rounded heal will burnish the cut as it's made and will make for brilliant clean lines.
Making a flat graver is probably the easiest to shape out. With it you can use it as a flat or turn it up on one of it's points and use it as a V or square graver. It cuts very nicely that way and you only have to shape one heel. Keep the sides parallel with the bottom so they don't drag in the cut.
