THE SMOOTH PROFILE OF
BUTTER PAT POLISHED CAST IRON COOKWARE™
Roughness is of critical importance in the casting industry but even more so in the frying pan business. Roughness equals stickiness in cookware because the valleys allow cooked particles to cling to a greater surface area, they get stuck and you get irritated.
We put a lot of emphasis in our early specifications; looking for a final finish in the range of 60-90 Ra.
We didn’t want to grind or mill to this finish, since those processes leave sharp edges on the surface, again contributing to a clingy cooking surface.
We derived our 60-90 Ra number by testing the surface of some exceptionally fine polished vintage pans in our collection. Cast in the early 1900s by the Favorite Stove Company of Piqua Ohio these pans are very smooth and their cooking surfaces smoothness averaged about 90 Ra.
THE MATH OF SMOOTHNESS
Here is a little of the math used to set specifications for smoothness in our industry.
Roughness parameters according to DIN EN ISO 4287/13565
Ra is one of several ways that engineers measure roughness of a surface. Ra is the arithmetic average (AA) deviation of the peaks and the valleys of a profile from a mean line over a measured length.
The math may be a little complicated but the necessary results are not:
The lower the Ra, the smoother the surface, the better the cookware.
Conventional cast iron (left) and Butter Pat (right)
A recent test we ran on our finish using a profilometer (an optical instrument that measures Ra) and the results.
We calculated our Ra at 57.36 using an average of three measurements.
Yes, our finish is smoother than the 60 – 90 Ra we planned!
AVOIDS SCRATCHING GLASS & CERAMIC COOKTOPS
Our cookware is not just milled and ground on the cooking surface. It is polished on all surfaces as was the best cast cookware of the late 1800s and early 1900s. This smoothness on all surfaces makes it a pleasure to handle and avoids scratching glass induction and ceramic cook tops.
IT IS VERY SMOOTH