Tolkowsky cut doesent work on the cut advisor (HIC)

[hunter3316]

I just put the numbers for the Tolkowsky ideal cut into the HIC cut advisor on this site and found that I get an error mesage (Girdle is to thin) and no prediction on the quality of the cut. I thought this quite strange. Does anybody have any reasons why this is? Shouldnt the cut advisor suggest Tolkowsky cut is good?

Tolkowsky #s are:
Table: 53%
Depth: 59.3
crown: 34.5
Pavilian: 40.75

source https://www.pricescope.com/tutor_tolk.asp

 

[Richard Sherwood]

The interesting thing about the original Tolkowski cut is that it had what is now called a "knife edge" girdle (extremely thin at the "valleys"). Totally impractical, and the HCA is alerting you to that fact.

Since then, the Tolkowski proportions have been modified by practical considerations to include an adequate girdle to avoid chipping.

Kinda funny, huh?

 

[Garry H (Cut Nut)]

Leonid set HCA up with some nice calculators that work out girdle thickness by subtracting calculated crown and pavilion heights and subtracting them from the depth % you enter.

So if the girdle thickness is too thin we just plain tell you to forget it.

For fun try adding 0.5%, then 1% in small increments and you will see a range of warnings.

We do a similar range for fisheyes.
If the crown angle is low, we change the advised minimum girdle thickness to stop the risk of chipping