How do they work or rather, how should they work?
Does doing the clamp up push the base of the fin onto the bottom of the box?
Or does it pull the pin up tight into the top of the groove?
Reason I ask is the fin in one board rocks lengthways - fore and aft.
It does the same with other fins - some more some less.
It pivots on the clamp end and the pin end moves up and down about 2-3mm.
I added about 3mm of glass to the tab (where the clamp pulls up to) helped a little but not much.
I put a new pin in about 2-3mm higher - no help.
The next idea is to put a larger diameter pin in - would that help? Groove seems quite wide and further down.
Or cut the box out (is it bowed?) and put another one in?
Any helpful ideas appreciated.
We used to cut some pieces of beer can and fold them over the fin as it goes in.
What kind of screw and plate are you using?
Those plastic ones with the lip on them (besides totally sucking in every other way possible) if in upside down will not allow you to clamp tight.
The plate should clamp up against the box.
Does your plate sit up against your box?
Metaco - are you saying shim underneath the fin - along the base?
That would mean the shim would press into the bottom of the box as the clamp is done up.
There is no sideways slop so couldn’t fold it around the fin.
WideAwake - stainless screw and plate. The clamp works fine, it is the other end that rocks up and down.
Perhaps the bottom edge of the tab should be tapered (down?) so that when the clamp pulls it forces the pin end up?
When it’s clamped down - is there a gap between the bottom of the tab and the screw plate?
Also if you have no screw I. It can you push the back down and still move the front pin up and down?
What’s the width of your slot and the top of your fin base (you’ll need calipers to get a good measurement)
Box may be warped - maybe your fin tab is too tall.
If the screw hits the bottom of the box the nut won’t be all the way tight to the top of it’s slot. sometimes the boxes get set too high and when sanded down the screw is too long. You should shorten the screw if it hits the bottom. Folding the thin beer can material over the bottom is not as hard as it seems once the sides are really tight the fin won’t move anywhere. The only other possibility is the pin is in the wrong spot which can be changed with a hole drilled in a new spot if there is room on the tab. I’d try a different fin and see if the problem remains. First check the fin against some fins in the store by eye to see if there is something funny with the pin placement.
WA you have hit on it - without the clamp and therefore the tab up higher - no rock at the pin end.
Therefore a thicker tab or spacer under the tab should do it.
Thanks for the suggestions.