These special cylinder shaped bolts are used to retain rear wheel Belt Drive rims to the rear wheel of Beaded Edge rims on Edwardian belt drive motorcycles.
They are cross drilled to be fed onto 12 Gauge (2.55 mm) spokes, and then have a small head and nut that feeds onto your belt drive rim. Each assembly consists of a small barrel (crossdrilled) fitted with a 4mm grubscrew (to lock the barrel to a 12 Gauge spoke, once in position and the rim is centralised, 2 stainless washers and a nut that is on the other end of the barrel - that attachs to a hole in the circumference of the belt rim - 5 small parts in all. All parts are in stainless steel.
These are sold as Each - (you will need to check your belt rim to decide how many you will need to use for your model, up to 10 seems to be the norm).
To give a bit more background: Most pre-1920 Edwardian motorcycles used belt drive final transmission. To do this, there were various types of 'spun' belt rims, which employed short spokes to attach them to the (beaded edge) tyre rim, but also needed some form of attachment to the spokes themselves, to avoid lateral movement of the belt rim. The rim shown in the photograph is an original Douglas 2 3/4hp rim of @1912-1918 vintage, and has a lip with holes in the lip for this purpose. When I purchased this Douglas restoration project, this very rusty belt rim had a small original steel plate about 1cm long wired to it, which had two small holes, threaded to take screws. Therefore it looks like the original method of retaining the rim to the spokes was to feed two small screws through the lip of the rim - one fed either side of the wheel spoke, and screwed into the steel plate behind the spoke. Originally I was going to replicate these plates, but I thought it would like quite ungainly and messy, and had seen another belt drive motorcycle using a type of retaining bolt similar to the ones listed here - and thought it looked a far more elegant and clean solution.
Each 'bolt' is CNC manufactured from 0.250" round stainless steel, with a 2BA thread machined on one end (to feed through the hole in belt rim lip), and drilled and threaded to take a 4mm x 0.7mm hex head grub screw on the other end. Each cylinder is then crossdrilled to allow it to be fed onto a 12 gauge (2.6mm) spoke, again this is part of the CNC manufacture.
Each cylinder type bolt is supplied with the hex grub screw already fitted, and two 2BA pan washers fitted and 2BA nut, ready to fit. All parts are in stainless steel. Method of fitting: you will need to feed each bolt onto the wheel spoke before commencing the main wheel re-spoking, but these can then be left until you have completed the main wheel spoking operation. I can see my original Douglas Belt rim looks to have used 8 retaining plates, however, I think using 10 means one bolt every 4 spokes, which should cover most types of belt rims. Then the next step is to 'spoke' the belt rim to the beaded edge wheel rim. when you commence this operation, also fit the belt rim laterally to all the pre-fitted 'cylinder bolts', but do not tighten the grub screw or the 2BA nuts at this stage. Finish spoking the belt rim to the tyre rim, to ensure it is absolutely central. Finally tighten the 2BA nuts and then the grub screws to the spokes to finish the operation, and check still all central. I would also advise using Threadlock on both grub screw and 2BA screw on final tightening, to avoid them loosening off in use.
Note - we can sometimes supply 12 gauge stainless spokes etched black (as shown here) to fit Douglas 2 3/4hp hubs and belt rims - see Item 0804 (but please confirm your required spoke length correct when ordering