Something to keep in mind is that all LPs are different- so the 92 degree SRA should be considered an approximation.
The simple fact of the matter is that the cutting stylus only lasts about 10 hours before replacement is required to continue doing low noise cuts on the lacquer. To replace the stylus, the cutting engineer has to remove the cutterhead from the lathe to do the job. Once done, it is then a matter of re-installing the cutterhead and getting it to work right again. That involves a number of test cuts until a number of the variables are worked out. These include stylus temperature, cutting angle, cutting depth and pressure (similar to tracking pressure, but cutting instead and somewhere between 60 and 70 grams is typical on our cutterhead).
The simple fact is that while you have to have a certain rake angle, in practice it might be 92 degrees and it might not. What it is will be whatever was required to get the cutterhead to cut a groove properly. As a result, all LPs are slightly different; 92 degrees is a good average.
The simple fact of the matter is that the cutting stylus only lasts about 10 hours before replacement is required to continue doing low noise cuts on the lacquer. To replace the stylus, the cutting engineer has to remove the cutterhead from the lathe to do the job. Once done, it is then a matter of re-installing the cutterhead and getting it to work right again. That involves a number of test cuts until a number of the variables are worked out. These include stylus temperature, cutting angle, cutting depth and pressure (similar to tracking pressure, but cutting instead and somewhere between 60 and 70 grams is typical on our cutterhead).
The simple fact is that while you have to have a certain rake angle, in practice it might be 92 degrees and it might not. What it is will be whatever was required to get the cutterhead to cut a groove properly. As a result, all LPs are slightly different; 92 degrees is a good average.