Maltese cross on barrel

[steve1811uk]

Hi, Any ideas how to deal with this? Ideally I need to dismantle, clean and reassemble. From what I can make out there is some kind of pre-load applied to the mainspring. Hope someone knows. Steve 

[nickelsilver]

Grab the square on the other side and wind a few degrees of turn, pull off the finger, then release the prewind (usually 3/4 to 1 turn). When re-assembling, wind up the same pre-wind, then place the finger on- with the cross oriented correctly.

 

I usually grab the square in a watchmakers bench vise. But you can use a pin vice... but you either have a lot of experience, are lucky, or have 3 hands there.

[RichardHarris123]

I have come across these before but the bit connected to the arbor was missing.  What's the correct terminology? 

[watchweasol]

The Maltese cross or stack Fred was designed to use the middle tension of the mainspring thereby keeping the power curve constant no high power or low power on full wind and low when the spring runs down.

[RichardHarris123]

What's the part connected to the arbor called?

[oldhippy]

Also called a Geneva, Stop Work. The part that fits onto the arbor is called the finger the other part is called the star wheel. The stop work also makes sure the mainspring can't slip off the arbor 

[steve1811uk]

Well, I took the plunge. Following advice, I held the barrel arbor in a pin vice and then held that pin vice in my bench vice. Holding the barrel so it didn't unwind I carefully levered off the finger. That part appeared to be a wedge fit onto the arbor. Once that was off I allowed the barrel to turn slowly anti- clockwise, holding the barrel between finger and thumb. It came to a stop after turning 315 degrees. Putting it back I will need to turn 315 degrees clockwise before fitting the Maltese cross. Thanks everyone who helped. Steve.

Edited March 19, 2023 by steve1811uk
Added image

[RichardHarris123]

I found this video