Dimensional characteristics of 33 rpm phonograph records (R.I.A.A.)

Dimensions Disque Vinyle • R. I. A. A. Dimensional Characteristics • 33 rpm • Phonograph Records For Home Use

Description 7″ record 10″ record 12″ record
Unit millimètre inch millimètre inch millimètre inch
Outside diameter 174.6 ±0.8 6.875 ±0.031 250.8 ±0.8 9.875 ±0.031 1301.6 ±0.8 11.875 ±0.031
Thickness
1. Flush design 1.9 +0.3/-0.4 0.075 +0.010/-0.015 1.9 ±0.3 0.075 ±0.010 1.9 ±0.3 0.075 ±0.010
2. Contour design See figure above See figure above
Center hole diameter Same as 10″ 7.26 +0.025/-0.05 0.286 +0.001/-0.002 Same as 10″
Center of gravity Same as 10″ 11.1 0.437 Same as 10″
Lead-in spiral¹
1. Starting To start at record edge
2. Grooves/inch Same as 10″ 16±2 16±2 Same as 10″
3. Contour The contour to be same as recording grooves
Margin diameter 172.2 6.781 246.8 9.719 297.6 11.719
Diam. outermost groove at pitch 168.3 max. 6.625 max. 241.3 max. 9.500 max. 292.1 max. 11.500 max.
Recording groove contour
1. Included angle Same as 10″ 90° ±5° 90° ±5° Same as 10″
2. Bottom radius Same as 10″ 0.006 max. 0.00025 max. Same as 10″
3. Width – Monophonic Same as 10″ 0.056 0.0022 Same as 10″
4. Width – Stereophonic Same as 10″ 0.025 min. 0.0010 min. Same as 10″
Minimum inside diameter 108.0 4.250 120.6 4.750 120.6 4.750
Runout of recording grooves
Same as 10″ 0.41 max. TIR² 0.016 max. TIR² Same as 10″
Lead-out spiral³
2 to 6 grooves per inch 2 to 6 grooves per inch 2 to 6 grooves per inch
Stopping groove, closed concentric circle
1. Diameter 98.4 +0.0/-2.0 3.875 +0.0/-0.078 106.4 ±0.8 4.187 ±0.031 106.4 ±0.8 4.187 ±0.031
2. Width Same as 10″ 0.08 0.003 Same as 10″
Rotational speed ±0.5 % 33 1/3 rpm 33 1/3 rpm 33 1/3 or 45 rpm
Direction of rotation Clockwise when observer faces side of record being played
Crossover spiral The number of grooves joining successive bands on a record shall not be less than 16 per inch
Strobe discs to download
→ Turntable Strobe Disc 50 Hz → Turntable Strobe Disc 60 Hz

Notes:
1 – In addition, there shall be at least one complete unmodulated groove at recording pitch
2 – This total indicated runout (TIR) measurement is to be independent of recording pitch
3 – The number of grooves per inch shall be so chosen that the spiral contains at least one complete revolution