THE "S MODELS"
The most commonly available, and probably the range that ensured Summit gained a reputation for conservative design - I hope that by exploring this area you will come to the conclusion that the reputation is unjustified!
There are a plethora of variations within the S range. I have decided to cover the main models individually, and most now have a well populated area (S.100 and S.175 are good starting points for the newcomer). The 'oddities' will be covered in number order below, as I have time to upload details:
S.60 - Black Hard Rubber
Possibly the earliest of the S models, I believe it was only manufactured in BHR, and dates from 1929. 5 1/16" in length, CL lollipop lever, and "Summit Velvet Tip" barrel stamp. This example carries a warranted 14ct nib
S.77 - To Follow
S.80 - See S.75 Section
S.90 - A Button Filler
The quality would suggest that this pen dates from the early years of the 1950's when Summit were in decline. The barrel stamp, below the barrel thread, and the bayonet type pocket clip, would confirm this date. Like the somewhat larger S.170 button filler, there was little effort made to advertise these pens, and they can now be considered a rarer find.
S.112 / S115
These models are near identical, with the only noticeable difference is the S.112 (lower pen) is of slightly wider girth. 5 3/16" in length, both came fitted with a Summit 14ct nib, and both have the "Summit Unbeakable" type barrel stamp
S.121 - (The Giant of the range)
This model dates from 1936, and is to my knowledge the biggest pen produced by Summit. It even exceeds the dimensions of the H.120 model that it succeeded. Its length is modest at 5 3/8", but a girth in excess of 7/16" make it a real handfull.The Summit branded nib is probably a size 6, and the barrel stamp is the "Summit Unbreakable" type.
S.130 - Included within the S.160 Section
S.165 - I thank Olle Hjort for providing a picture of the S.165, a button filler that clearly hails from the last years of the company.