Measuring Piano Hinges for New Hinge Pins (Piano Tuning and Repair)
Welcome to our Series on Piano Tuning and Repair.
When you've lost the hinge pins to the lid on your grand piano, sometimes it's difficult to determine which size pins you need. The demo video above shows how to do an estimate measurement with drill bits to determine which size pins you need.
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Welcome to this next video from Howard Piano Industries. We're going to be showing you today how to measure your piano hinge for the right size of hinge pin. So when a lot of times we'll get calls from people that have lost the pin that holds the hinge. You know a grand pianos especially they'll have a hinge, usually two of them that hold the lid on to the body of the piano and often well get calls from piano movers that they because they take the hinge pins out because they remove the lid and they move the piano and then all of a sudden they've lost the pins. So then they don't know what size pin that the piano uses. So we're going to show you today how to do an easy way if you don't have the pins to figure out what size hole the hinges have for the pins.
Using Drill Bits for Measurement
Typically we use drill bits. I've got some different sizes of drill bits here. I've got a let's see I think this one's a 1/8 inch which will be equivalent to 0.125 inches. If you want to convert the standard size drill bits like that are that are in fractions to a thousandth of an inch decimal point which is how we've got them sized is you just do a division problem. So like 1/8 would be just 1/8 you can do that on your calculator 1/8 is 0.125 inches.
I've got a drill bit here that's 9 let's see 9/64. 9 divided by 64 is a hundred and four about a hundred and forty thousands. Which we do have a hinge pin that's 140 thousands. That's a fairly common size for grand pianos and then so if you've got a 9/64 inch drill bit and it fits in the hole fairly easily. Now this one here you can tell is probably a little bit too loose. It just slides in and it's got some wiggle room. The most common size now which is even more common than the 0.140 is the .150. So here I've got a drill bit that's 9 I don't know what is it five 5/32.
Okay so if I did on the calculator 5/32 come up with one .156. Okay so this one you know if I've got a I've got a .150 .150 inch pin and my 5/32 inch drill bit. Okay so that that fits but it's a fairly tight. I mean if that's what you get or if it the .140 inch drill bit or the what do we call this we call this 9 9/64. If that is in there and it's loose and then the 5/32 goes in there and it's too tight then you're you're probably going to need a .150 inch hinge pin. okay and again that's the most common size. Then you know and if you've got bigger like some of the pianos have larger hinge pins then you go to larger drill bits and go through the same process of trying to figure out which which size or at least get a rough estimate of which size hinge pins your piano uses.
So that's a fairly easy way. Again we get a lot of calls people ask how do I know which size hinge pin that I need to order and this is the way to do it. So if you have any questions feel free to let us know.