| Westclox | Big Ben Style 7 | Base | Some have a single digit cavity number only, some say "75-102" with a cavity number such as "1 A" or "2 A". |
| Westclox | Big Ben Style 7 | Base Cavity Number | Base 1 has a single digit cavity number. Base 2 has been seen with "1 A" through "4 A". |
| Westclox | Big Ben Style 7 | Bezel Color | BLACK Big Ben style 7 has a nickel bezel at first, changed to brass ca. 1960. |
| Westclox | Big Ben Style 7 | Hairspring Fastening to Stud | Early examples are pinned, most are glued. |
| Westclox | Big Ben Style 8 | Back Patent | The first backs did not have a patent number, after about a year a patent number was added. |
| Westclox | Big Ben Style 8 | Base | A metal base was used first (with two types of lettering), followed by a plastic base. |
| Westclox | Big Ben Style 8 | Base Cavity Number | A single digit number. On metal bases, I've seen numbers up to "3". On plastic bases, I've seen number up to "8". |
| Westclox | Bingo Style 1 | Case Clamp | First, a long narrow steel clamp. Later, a small brass rectangular clamp. |
| Westclox | Bingo Style 1 | Leg Width | First, the legs were 1/4 inch at the hex portion. Later, they were 7/32 inch. |
| Westclox | Four Inch Movement | Back Logo | Some from before 1910 into the teens have a maker's logo or MADE IN USA on the back. |
| Westclox | Four Inch Movement | Balance | The construction of the balance (the timekeeping element) was changed several times. |
| Westclox | Four Inch Movement | Motion Pinion | The motion pinion (also called minute pinion or reduction pinion) is cast of lead alloy in a few early examples that I have observed. In most clocks, the motion pinion is brass. The September 22, 1885 patent, on which Westclox clock construction was based, describes casting clock parts of a lead alloy. |
| Westclox | Four Inch Movement | Patent Form | The form of the patent stamping on the back of the case. |
| Westclox | Four Inch Movement | Plate Shape | The shape of the front and back movement plate. |
| Westclox | Model 66 Movement | Alarm Set Knob Fastening | Early 66 movements have screw on knobs, later they are staked. |
| Westclox | Model 66 Movement | Gear Material | Most 66 movements have brass gears. Waralarms have steel gears. Late 1950s examples have steel gears. |
| Westclox | Model 66 Movement | Minute Wheel Fastening | Early model 66 movements have no minute wheel fastening, or a c-clip. Later, it was fixed in place by a stud. |
| Westclox | Model 66 Movement | Movement Date Location | Model 66 movement date location varies by date made and where made (USA, Canada, Scotland). |
| Westclox | Model 66 Movement | Movement Material | Early 66 movement plates are brass, they are steel during WWII, later ones are aluminum |
| Westclox | Siesta | Dial | This applies to black clocks (not ivory). First, the dials were plain inside the numerals. Later, they had a printed square inside the numerals. |
| Westclox | Siesta | Key Handle Shape | Sausage-shaped handles used at first (like the style 3 Bens had). Regular key shape came second (like style 4 and 5 Bens). |
| Westclox | Waralarm - Fiber Case | Back Type | Early examples have a price label, later ones have the price imprinted in the back. |
| Westclox | Windup Clock | Alarm Click | Westclox kept changing their winding ratchet mechanism. The first four types listed here engage with projections pressed out of the body of the mainwheel. |
| Westclox | Windup Clock | Time Click | Westclox kept changing their winding ratchet mechanism. The first four types listed here engage with projections pressed out of the body of the mainwheel. |
