Player Piano Revival Episode 13: Review of the Tracking Device // How it Works 

Looks like you're right on track! Minor detail, but at 1:53 you're meaning the left side chuck, yes? A very edutaining vid, well done!

Very well explained, a complex mechanism indeed. And your outtakes at the end were enjoyable! Good doggie!

I am always blown away by what they managed to create back in the day without electronics. That pneumatic self-correcting mechanism is pure genius.

poor dog, I can hear him "how many times!" very clever little box. great video 2x👍

I can’t thank you enough for your videos.

Such a cute dog! Very smart too.

I just discovered this video series, just a few weeks after taking on my wife's grandmother's 100 year old player piano to restore and get running again. Having a visual walkthrough of how to tackle this is a HUGE help! Thank you so much Nate for taking the time to make these extremely helpful videos. I have confidence my own project will be a success thanks to this!

Pneumatic logic gates! Gotta love analog tech!

Okay I watched hard but I'm still pretty much baffled. But I will wrestle with it until I understand. I find it most impressive that these wooden vacuum passages and valves are enduringly airtight. Are they lined with rubber solution or something or is it a particularly dense timber? Or am I just particularly dense for finding this unusual? Thanks for this Nate, this series is endlessly fascinating and intriguing. The level of engineering is utterly astonishing; it's amazing they work at all, let alone so brilliantly! Thanks again.

That's such a clever feat of engineering. Nowadays it would be electronic and likely using optical sensors, but this pneumatic device made mostly from wood is so elegant.

I like how you included an audio clip of the mistracking roll “Bow Wow” at the end so we can hear what it sounds like when the roll doesn’t track and ends up randomly changing keys!

Another great video, always entertaining. The museum I work at in Pennsylvania has probably over 100 thousand rolls of all types, kept in 2 building. Maybe I will make a video of them. They also have a Lazer roll cutting machine. The company was named Valley Forge Music Roll Co. But it's not really running anymore.

You need a sonic cleaner for all the hardware. I rebuilt a Story & Clark player piano. It used mechanical "ears" rubbing on the paper's edge & a friction device to track the roll. That has the same problem as the pneumatic scheme you show. The ears can also catch on the roll edge & make tears worse. My concept for a roll tracker is to have in the tracker bar, below the line of "playing" holes, a 2nd line of holes. This line would have double the number of holes (18 to the inch versus 9 to the inch for the playing holes) aligned so there are 2 holes directly below each playing hole. Every other hole (all the ones below & to the left of playing holes) would be connected together, & the same for the ones to the right of the playing holes. These 2 lines would go to the tracker valve box. When the roll is properly centered, each playing hole will admit the same amount of air to both sets of tracker holes, so the tracker remains stationary. It would also remain stationary when no air is admitted to either set. When the roll shifts, this balance would be upset & the tracker would re-center the roll. As long as the roll were initially centered, & there were not too long periods of silence, the roll could remain centered even if the edges were totally chewed up. This would even track rolls that were punched skewed. Have you ever encountered such a system? I would have tried this but at the time I was in Jr high school & did not have access to a machine shop to make that bar.

Thanks! This video helped a lot

I need a valve repair in my brain to get it all...

I found the blue mouse at 8:42

He knows which ones are " dog eared ", to put in the bin!🧐

I have a technical question about the tracker bar's four (4) far edge holes (2 on each sides) that keeps the paper centering ok. Let's say we call the 4 paper centering holes A, B, C and D. 'A' would be the far left one and 'D' the far right one. Are A and D to be the only considered holes to check for the wider paper rolls to auto-center ? and B and C to be the only considered holes to check for the narrower paper rolls to auto-center ?

Interesting how your tracker bar has 2 holes on either side, mine only has one on either side and the pneumatics on the aligner are flipped so the hinge is on the bottom! Technology improved so fast back then. I don't remember when your piano is from, but mine is from 1888 so it certainly had more janky mechanisms.

The machine I’m fixing only has a manual cantering device