Warning please read this
well, if you think about how those pin backs work, it's pretty obvious they would cause damage. the part you tighten is on the side, midway down the post. when you tighten something like this with a wrench, you are forcing a column inside to push against the thing you are tightening it to. we should all know how easy pin posts are to bend, so when you imagine holding your pin back and pushing a metal bar into the middle of it super hard, it just makes sense that it would bend it.Hope you all know that this is really serious and WILL wreck your pins. PLEASE don't take this lightly. I am talking from experience and don't want the same thing to happen to you.
but, of course, that's only if you think about the mechanics. normally, you wouldn't expect a product to cause damage doing what it was designed to do. talk about a design flaw...