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walpurgis
22-10-2015, 11:34
Can anybody email me a scan of a Decca FFSS arm mounting template and tell me the distance from stylus to mount centre, just so I can correct for errors?

Or, even better an unwanted actual template would be great.

This is for the later arm with the parallelogram shaped counterweight. Mk.II/Mk.III I believe, if that makes a difference.

I can manage without, but it would make life easier.

BTW Deram arm template won't do. Geometry is different.

Thanks.
mad-moon
22-10-2015, 15:37
The distance is 8 and 3/8 of an inch...or 213mm...the same as my Decca London international...in fact the template I have says on the rear..."Decca ffss INTERNATIONAL ARM"...I'll scan the template after my tea and send it to you...Alan.....

P.S. the earlier arm..has a distance of 8.5 inches.
Barry
22-10-2015, 17:48
Why do you need to know the stylus to mount distance (stylus to arm pivot distance), as this cannot be adjusted? Surely what you need is the distance between the turntable spigot and the arm mounting.
walpurgis
22-10-2015, 17:57
Why do you need to know the stylus to mount distance (stylus to arm pivot distance), as this cannot be adjusted? Surely what you need is the distance between the turntable spigot and the arm mounting.

I'm likely to be making up a sliding arm base and want to take everything into account before I decide the centre position for the slide adjustment of the base.
Barry
22-10-2015, 18:12
Ah - understood.
walpurgis
22-10-2015, 18:15
Ah - understood.

I thought making one with brush finished lacquered brass might look tasty. :)

Toying with using Dzus fasteners to lock/release the slide. Could work, if I can find suitable items.
mad-moon
22-10-2015, 18:30
Oops...I've misread that totally...haven't I..??..:doh:
Barry
22-10-2015, 19:21
Oops...I've misread that totally...haven't I..??..:doh:


No not at all. The figure you quote (8 3/8") is the distance geoff is looking for. It is the distance between the turntable platter spigot and the centre of the arm mount (i.e. the arm's pivot in the horizontal plane).

The effective arm length (distance between the stylus and the arm pivot in the horizontal plane) is 9". This makes the overhang 5/8" (= 15.875mm).


The null-radius is 2 3/8", thus the arm conforms to Stevenson's geometry; typical of British-made arms of the time.