Bell Gong/Striker Spacing - UK Vintage Radio Repair and Restoration Discussion Forum

Monteey · 30th Nov 2010, 3:53 pm

Hi
This may seem like a bit of a silly question, but im curious to know what is classed as the optimum spacing at rest between the bell striker and the gong on a 746.
Currently when refurbishing them i tend to leave a 1-2mm gap between the striker pushed to its limit manually on the coil, and the gong itself, is this wrong, should it be in contact with the gong on its limit or should the gaps be different for each gong?
Adjusting the spacing obviously makes a difference in the volume of the bell but im finding if its done wrongly the phone sounds more like its brrr-ing instead of ringing!

Many thanks for any replies, hope ive made sense!

russell_w_b · 30th Nov 2010, 4:59 pm

I would adjust the gongs such that operating the armature smartly by finger (the armature is the bit that pivots on the end of the bobbins, and is attached to the hammer) causes the hammer to strike the gong and lift off immediately to rest, i.e: the hammer will be attracted to travel to hit the gong beyond its 'rest' position.

If you then move the armature softly, the hammer should not touch the bells. There is scope for adjustment of the magnet in the 59A bellset - can be set up for 50Hz, for example - but if it hasn't been tampered with in the past, I would limit your adjustment to the gongs themselves. There's a good bit here about bell adjustment. Your available ringing current will make a difference as well, especially if it's very weak.

30th Nov 2010, 3:53 pm	#1
Monteey Retired Dormant Member Join Date: Aug 2010 Location: Yeovil Posts: 1	Bell Gong/Striker Spacing Hi This may seem like a bit of a silly question, but im curious to know what is classed as the optimum spacing at rest between the bell striker and the gong on a 746. Currently when refurbishing them i tend to leave a 1-2mm gap between the striker pushed to its limit manually on the coil, and the gong itself, is this wrong, should it be in contact with the gong on its limit or should the gaps be different for each gong? Adjusting the spacing obviously makes a difference in the volume of the bell but im finding if its done wrongly the phone sounds more like its brrr-ing instead of ringing! Many thanks for any replies, hope ive made sense!

30th Nov 2010, 4:59 pm	#2
russell_w_b Dekatron Join Date: Jul 2007 Location: Penrith, Cumbria, UK. Posts: 3,687	Re: Bell Gong/Striker Spacing I would adjust the gongs such that operating the armature smartly by finger (the armature is the bit that pivots on the end of the bobbins, and is attached to the hammer) causes the hammer to strike the gong and lift off immediately to rest, i.e: the hammer will be attracted to travel to hit the gong beyond its 'rest' position. If you then move the armature softly, the hammer should not touch the bells. There is scope for adjustment of the magnet in the 59A bellset - can be set up for 50Hz, for example - but if it hasn't been tampered with in the past, I would limit your adjustment to the gongs themselves. There's a good bit here about bell adjustment. Your available ringing current will make a difference as well, especially if it's very weak. __________________ Regds, Russell W. B. G4YLI.