PR: Proprietary Items Rev. counters. (tac)

[vibrac]

Now I believe vin rev counters are 4:1 ratio anti clock and the timing drive gear is 2:1
I have a working Smith's on my flash and may well need another set
Now I have always supposed that the epethet "anti clock" refers to the direction of rotation of the cable inner viewed at the clock end
My puzzle is the the flash needle goes clockwise as does any other I have encountered but if I look on evil bay I see 4:1 revcounters described as "anti clock" and showing clocks with a face scale that is obviously set to to a needle that revolves anti clock wise
My understanding of years is threatened

 

[davidd]

Tim,

I am not sure this will answer your question, but I did not believe that the direction of the needle was related to the direction of the cable. I assumed the instrument itself was numbered and geared for the correct rotation of the instrument's needle or hand specified by the manufacturer regardless of the cable rotation. However, I have been using electronic tachs, so I am not that familiar with the cable to head relationships.

I am familiar with the rotation, which Smiths called "reversing or non reversing." The rotation is specified from the direction of the magneto armature as it is installed. A clockwise turning shaft gives anti-clockwise cable rotation.

The BG1507 series tach drives are available in 5 models: two 1:1's (reversing and non reversing) and two 8:1's reversing and non reversing. The Vincent is the one in the middle, BG1507/3, which is the 4:1 reversing. There is no 4:1 non reversing model in this series

David

 

[vibrac]

Yes David I think that an ebayer or two is getting the anti and clock wise relationship wrong in their adverts
I think they think rotation is needle direction not cable (complicated init?)
eg https://www.ebay.co.uk/itm/Replica-...759700?hash=item1cd8863a54:g:Z6QAAOSwLnBX9R7u
obviously it could be either direction cable (unless you know your BSA's)
The Indian ones are even worse they dont even give a cable rotation....
and of course replicas dont give the smiths R numbers