Alpha Bearings, UK....a look into some older master catalogues in particular for Velocette information...

Alpha Bearings Limited are a company well known in English motorcycling circles for big end assemblies....
Actually they have made other items over the years including engine valves, small end bushes, valve guides and after acquiring the Romac Cable making business, supplied speedo and tacho cables as well amongst other things.
Situated in Kingsley Road, Netherton near Dudley in the West Midlands of the UK, I remember when I first visited them on a business trip in September 1986. I'd borrowed a BMW R100/7 from a long time UK friend, Elvin Bitchell to run around the UK and Europe ( a cheapskates business trip...actually I relished the riding and camping it entailed...but that is a story for perhaps another post..) visiting various businesses of interest, predominately speedometer oriented, and so Alpha were on the list.
It was one of the "hole in the wall" type entrances and some shock when I came upon it riding slowly down Kingsley Road...

Entering the open door I advanced down a darkened passage to one of those half doors such as you find in a horse stable, the top half open..."hello in there!" ...a friendly face appeared and we introduced each other....
Enough of the preamble, I've several Alpha master catalogues I want to share data from with you, this will be Velocette oriented, but for others, the introduction side of the catalogues make interesting reading.
Perhaps I'll publish a more complete listing for other motorcycle brands at a later date...
I've one catalogue up to 1953 and the other up to 1966.
Lets look at the 1953 one first...
I acknowledge copyright to Alpha Bearings Ltd., who are still actively in business...
Left click on the images to enlarge them all for better viewing....

The 1953 catalogue cover...the books came from a now defunct Sydney Motorcycle Accessory firm, Omodies Ltd., and as you can see by the stamp on the top of the cover the Australian importer for Alpha at that time was Eustace G.Jones in Melbourne, Victoria.

Flyleaf for the 1953 catalogue....
Following are information pages from the 1953 catalogue, omitted in the 1966 edition...

The 1966 Alpha Bearing catalogue cover...

The introduction of the Alpha Tru crankshaft truing jig for 1966...

Alpha small end bush listing to 1966, covering Velocette.

Alpha small end bush codes for Velocette to 1966.

Alpha big end codes and dimensions covering Velocette to 1966.

Interesting information....
The codes....
V1..... 1932-1940 GTP
V2.....1934-1948 MOV
V3.....1934-1960 MAC and 1936-1948 KSS MK.2
V4.....1935-1948 495cc, 81 x 96 MSS
V5.....1938 Mk.7 and 1939-1950 Mk.8 KTT
V6/9..1956-1971 VENOM, VIPER and 1954-1971 86 x 86 MSS
V7......1957-1964 VALIANT
V8......1962-1965 VICEROY
Ever wondered what the big end bearing clearance was for an Alpha Velocette big-end, say the V6/9 for the 500cc Venom/MSS/ 350cc Viper?
Taken from the above chart.....
The internal diameter of the bearing ring for the con rod is 1.8765"
The diameter of the crankpin track is 1.500"
The diameter of two 3/16" rollers are 0.1875" x 2 = 0.375"
So.. 1.8765 less 0.375" less 1.500" = 0.0015"
A thou and a half....
When oiled guess you'd have difficulty in feeling any play in the newly assembled bearing.....