Hi, thanks for the reply.I saw there was a short piece in Alpinist 31, Rough timelines I'm aware of below, I'd be really interested if anyone has any source material that places exact dates for any of this as much of what I've gathered here is from secondary source material. Or equally if anyone knows of any other significant developments I've missed or can fill in blanks, gaps, earlier dates for any of the examples etc;Pre Screws -1924 - Fritz Riegle invents ice pitons (daggers) for use on the first ascent of the North West face of the Wiesbachhorn.1938 - first tubular style ice pitons (Rosegs? anyone know of any references in literature/images?) developed in GermanyYear?? - Soviet Warthog style pound in spiral ice pitons. (Does anyone know of any images of these, I've only found allusions to them in text)Ice Screw Era1960 - Erich Friedli invents first ice screw, "corkscrew" style - poor bendy material, very unreliable1961 Stubai Marwa Screw - mass produced corkscrew design based on above, very basic, still only marginally better than Friedli design. Mid 1960's - Milan Doubek (Czech climber) refines the Soviet Warthog design with slimmer profile to displace less ice and reduce shattering of ice. Shows these to Hermann Huber in 1965.1966 Salewa (Hermann Huber's company) starts selling mass-produced SpiralZahnHaken (before they were christened as Warthogs by Chouinard).1970 Chouinard starts importing Salewa tubular Ice Screws, SpiralZahnHaken and Stubai Marwa ice screws to USA.1974 Lowe Snarg - pound-in design, easier to place on lead, hard to remove for the second however. 1975/1976 Chouinard produces his own version of the Warthog 1976 Chouinard refines his ice screws to use thinner walls, larger bore, 4 teeth (first?) (source Mountain Magazine advert from 1976)1978 Mountain Magazine do an Ice Screw and Warthog test, Warthogs perform poorly and see decline in use on Ice routes (still useful in turf and still used to this day though) Chouinard & Salewa drop Warthogs from production.
1987 Lowe R.A.T.S - Ratcheting Aluminium Tube Screw - first aluminium screw? Wide bore.
Late 1980s?? Irbis Russian Titanium screws - light but not great. More commonly seen after fall of Berlin wall in 1989, but when were they first produced?
Late 1980's - Chouinard develops screws that could be placed one handed.
???? Smileys Organ Grinder Knob - first knob attachment for faciliating placement?
???? Black Diamond first folding knob? Polished inside and out screw first????? Grivel first Ice Screw with Reverse Threads for greater holding power - year?