This is a shouldered bolt of 0.710" shaft length, with the distinctive shouldered square head, of the type used on brake assemblies of early Douglas 2 3/4hp models. It is intended to feed through the circular locking ring used on early Douglas 2 3/4hp brake pedal assemblies, which is used to adjust the position of the brake pedal on its shaft. This bolt is an alternative to Item 0689 - it having a a 0.257" x 26tpi BSC thread. Please measure your original brake pedal lock ring thread/bolt to ensure you know the correct thread before ordering. It is CNC manufactured in stainless steel
I have made a small batch of these bolts as part of the restoration of my own Douglas 2 3/4 hp model, of which I am building as a 'loose' copy of a sports/racing version of this model - a Works model of which Douglas won the Isle of Man Junior TT with in 1912.
I copied this bolt from an original item which was part of a very rusty but original early Douglas front brake assembly - which I am almost certain was of the type of assembly fitted to the 1910-1912 models, to the front downtube. I have seen a very similar assembly and brake pedal fitted to period photos of this model - where it was not uncommon to have a two sets of footrests, the normal set just in front of the two speed countershaft, and another forward positioned assembly mounted at the base of the front down tube.
When purchased this front assembly was very rusty and dilapidated - but looked original and unmolested. The assembly included the brake pedal (see accompanying photos), original Douglas brake positioning lock ring and square headed bolt for that locking - which is the item copied here - CNC machined with a shouldered/milled square head in stainless steel
Although the square headed bolt was very dilapidated, I was able to de-rust it and used it as a template for CNC machining a copy in stainless steel, including lipped square head, which has been milled from round bar.
This particular bolt is an alternative to item 0689 - in that it is is still of 0.257" diameter (as per item 0689), but has been manufactured with a more common 26tpi BSC thread - in case your lockring has been re-tapped with a BSC thread. Read item description for 0689 before ordering this part - I am not sure if Douglas later manufactured this bolt in a 26tpi thread - but in case they did, I have also made a small quantity of the bolt in this listing - which is the same dimensions as Item 0689, except it is made with a 26tpi thread.
If I say so myself this bolt is very pretty, when polished looks almost indistinguishable from the original nickel plating of this era and will not rust!
Note: see also item 0689