Popping off a pinned top plate?

[polkat]

A two part question: Was just given a nice Strad copy dated 1922. Very nicely detailed; I don't think this was machine made. Anyway, there appears to be pins at the top and bottom of both plates (right at the edges in the centerlines). I want to pop the top to fix and cleat a small crack, but I've never pulled a top with pins before. Anything to watch out for?

The second thing is that the overstand of the neck heel above the top plate is just barely 5mm. I've always heard that 6 or 7mm is best. Is this a problem?

Thanks all!

[MANFIO]

In general we cut the pins. In general they are already cut on old instruments.

[Brad Dorsey]

The reason to cut the pins is that there's a good chance the top will not go back on positioned exactly as it came off, because the shapes of the top and of the rib structure will likely have changed from when the instrument was new due to shrinkage.

When I remove a pinned top, I sometimes find that the top lifts off the pin at the lower block rather easily. I saw the pin off and glue it back in its hole in the top.

[Brad H]

The second thing is that the overstand of the neck heel above the top plate is just barely 5mm. I've always heard that 6 or 7mm is best. Is this a problem?

Thanks all!

I will give this a go but note that I am not a pro...Most likely, the 5mm overstand wouldn't be a problem but there are other measurements which all play into this aspect of correct setup - the fingerboard projection at the bridge, the arching, the string angle over the bridge, and the saddle height. If the fingerboard projection is too low, then a fingerboard wedge or a neck heel lift/reset would solve both problems. If the projection is good but the string angle is off, the easiest remedy is to adjust the saddle height to get the correct string angle (I think it is 158 degrees).

If you search for "neck angle" or "string angle" you should find plenty of info.

By the way, what are some techniques for removing the pin that goes into the top block?

[Craig Tucker]

By the way, what are some techniques for removing the pin that goes into the top block?

Sawing or cutting the pin through. (with, for example, a razor saw)

Lifting the plate off of the pin. (I think, when this happpens, it is the best method)

Very carefully drilling the pin out. (though this is perhaps not the first choice, it can minimize damage to the plate)

Often, I will end up relpacing the pin so that hole in the top block has been filled, and the plate shows that a pin is still in place even though it is no longer going through into the block.

[Brad Dorsey]

By the way, what are some techniques for removing the pin that goes into the top block?

There's no reason to remove the pin from the block. Just cut it flush with the top surface of the block.

[polkat]

Well I got the top off rather easily, fixed the little crack, and got ready to cut the pins off. But first, for the heck of it, I tried fitting the top back on with the pins still intact. It fit perfectly!

So, any reason not to just leave the pins in?

Also, the bass bar was a little strange, but I'll start a different topic on that.

[Brad Dorsey]

So, any reason not to just leave the pins in?

The only reason that I can think of is that it might be easier to take the top off next time if the pins are cut.

[jezzupe]

I would leave them and simply not glue them or allow glue in the pinhole, which is what the last guy did for you which allowed you to pull it off so well.If the alignment is still good, I would use it.By simply not putting glue on the pin or in the hole it will remain free.The only caveat to that would be if the pinhole is honed out and has "sloppy" play that could allow for the pin to vibrate inside the pinhole, a small bit of candle wax stuffed in the hole will prevent any glue from squishing into the hole and will fill any void that may allow for a "splinter" vibration