Noisy Rack

[gleber]

Is this clicking noise normal for a tall case rack strike? Is there a way to reduce the sound of it?



Thanks,`
Tom

 

[Uhralt]

The video is a bit short but it seems that the click happens shortly before (or after) each strike? If this were a count wheel strike I would say it is the lever touching the count wheel and it is loud because a helper spring is too strong. But with a rack strike? Maybe it is the lever that prevents the rake from falling down after each strike on its way up. If there is a helper spring that might cause it to push too hard against the rake, causing the noise.

I video of the clock striking with the dial removed would probably answer your question.

Uhralt

 

[gleber]

Yeah, I need to reduce the resolution for a longer video - as it is I had to chop this one in half. The loudest clicking of most concern is just before the strike, so the second one is best. This is a rack and snail. Watching it, the noise is all associated with the lift and dropping of the piece above the rack in the upper left.

I have another similar unsigned movement that sounds the same, that is why I asked it if was normal.

Tom

 

[Uhralt]

Yeah, I need to reduce the resolution for a longer video - as it is I had to chop this one in half. The loudest clicking of most concern is just before the strike, so the second one is best. This is a rack and snail. Watching it, the noise is all associated with the lift and dropping of the piece above the rack in the upper left.

I have another similar unsigned movement that sounds the same, that is why I asked it if was normal.

Tom
View attachment 546064

Yes, this is the lever I had in mind. It falls by its own weight, no spring attached. The sound happens when it falls down from a tooth of the rack into the next trough. So, the sound is "normal". All you could do to minimize it would be to soundproof the case, but that's not something one would want to do (at least not me). Or, maybe it would help to glue a piece of rubber foam or similar to the side of the lever and/or the rack. That might reduce the vibration somewhat. Self-adhesive weatherstripping comes to mind. Probably it is best just to get used to the click.

Uhralt

 

[novicetimekeeper]

8 day strikes are noisy affairs, lots of whirring and banging.

 

[R&A]

Never had one that didn't make allot of noise They are very rustic

 

[bruce linde]

isn't that more the gathering pallet than the rack itself? you might try adjusting/smoothing the little pin that catches the rack teeth...

 

[Uhralt]

isn't that more the gathering pallet than the rack itself? you might try adjusting/smoothing the little pin that catches the rack teeth...

The gathering pallet is usually surprisingly silent in these movements.

Uhralt

 

[bruce linde]

i can see (hear?) the gathering pallet or rack hook being the problem, but the rack itself is just getting moved back into original position... not sure how it could be the source of the noise. the hook lifting in and out or the pallet (or pallet arbor?) spinning, more so.

 

[gleber]

The click clack is from the lever above the rack with the single tooth that engages the rack to hold it (what is the name of this lever?) and the rack.

The gathering pallet advances the rack and lifts the lever. The lever drops after the rack tooth passes and makes the first click when it lands on the rack. This holds the rack, but then the rack is moved further by the pallet and when the pallet finally releases from the rack, the rack spring pushes the rack back into the tooth on the lever above making the clack sound. The pins that lift the hammer and the hammer hitting its stop also make noise, but not as much. All three of my clocks with this style movement have that extra little advance of the rack causing the clack sound. I therefore assumed it was normal - maybe the clack is not? I wonder if lining the tooth on the lever with some sort of thin softer material with good wear properties would reduce the harshness of the sound?

I don't really want to take off either dial from my two running clocks and my third movement is apart for cleaning. I may experiment and post videos once I get the third one going.

Tom

 

[bruce linde]

i think it's called the rack hook.... i've had some luck smoothing surfaces on the hook and the rack teeth, but there's a lot of motion there... might want to double-check the bushings....

 

[gleber]

Update. I took some videos of my movement that is in the queue for cleaning. I only assembled the necessary parts and rotated the gather pallet by hand.

The first video shows the lever drop and its tooth make the click sound, then the rack rotating back after it's released from the pallet and hitting the tooth making the clack sound.



Here is a video of the normal sound. There is no resonance, so it is not as loud as when it is in the clock.



I then put a piece of masking tape on the faces of the tooth on the lever, Here is a video of the sound dampened some and the tape seems to have filled the space to eliminate the clack from the rack falling back and hitting the tooth. Masking tape will not hold up, but this does prove the dampening concept works.



Yeah, science!

Tom

 

[bruce linde]

you're getting a double-click... and the masking tape is just making it a single click.

not sure there's a way around that, but you might want to get in close with magnification and see if you can figure out why the double-click is happening. i wonder if a rook hook tip made out of delrinAF would work? hmm.....

 

[bruce linde]

p.s.: why the short videos? just dump 'em up on youtube no matter how long they are and then embed here.

 

[Uhralt]

Usually I wouldn't recommend this because levers generally shouldn't be oiled at their pivots. They should be allowed to fall freely. But if the sound really bothers you, you could try a highly viscous oil on that pivot (or stem) to make the lever fall more controlled (speak more slowly). That should make the click less loud. If you use synthetic oil there is less of a chance that things will get too sticky over time. You may even want to try a grease if the oil isn't viscous enough.

Uhralt

 

[gleber]

you're getting a double-click... and the masking tape is just making it a single click.

not sure there's a way around that, but you might want to get in close with magnification and see if you can figure out why the double-click is happening. i wonder if a rook hook tip made out of delrinAF would work? hmm.....

Yes, the masking tape seems to fill most of the space that the rack advances so it can't fall back as much and it doesn't make a clack.

I know why the double click is happening. The tooth falls (click) and the pallet continues to move the rack past the point where the rack hook tooth drops. When the pallet releases the rack, it falls back and hits the tooth (clack). This is probably to ensure the tooth drops and doesn't get hung up on the tip of the tooth, It if did, it would run on or at least double strike.

I like the Delrin idea. Or maybe I could dip it in that tool handle coating stuff. I definitely won't do anything that is not reversible, and maybe nothing at all. At least this has been a fun investigation / thought experiment.

Tom

 

[gleber]

p.s.: why the short videos? just dump 'em up on youtube no matter how long they are and then embed here.

Lazy creature of habit. I take the videos on my phone and email them to my computer to store them in my clock folders and then upload to Youtube from there. I keep them short since there is a limit on email size. I know I could load them to Youtube from my phone, but I still want them on my computer. I know I can use a USB cable to transfer them, but that means I have to go find one. I have a Thecus NAS and on my old phone I had an app that automatically pushed new photos and videos to the server, but when I got my new phone, the app didn't transfer and is no longer available on the Play Store (at least I cant' find it). The new Thecus app doesn't seem to have that feature.

Jeez, I look back at my fist sentence and realize it would have been easier to just say, "Good idea Bruce."

Tom

 

[shutterbug]

Is the rack hook weighted or spring loaded? That might be causing it to be so loud. The way the GP is constructed makes an adjustment there a no go.

 

[gleber]

The rack hook is not weighted or spring assisted. It is a thick piece, not just a thin stamped piece, so it has enough mass to make the noise on its own.

Yes, there does not appear to be any way to adjust the gathering pallet. I suppose I could file its lifting tab so it doesn't push the rack past the rack hook as far and then it wouldn't spring back and make the clack sound. But, that seems like a really bad idea - both on principle and for reducing the tolerance that currently ensures the rack is ratcheted far enough for the rack hook tooth to engage.

I may continue to explore options to dampen the sound. For example, rather than coat the faces of the rack hook tooth with something soft, I could add something to stop the rack hook from dropping far enough for the tooth to hit the rack. The tooth doesn't have to land in the bottom to lock the rack. It could be a small post with a leather pad or something like that to arrest the rack hook just before the tooth hits the rack.

Again, this is as much of a thought experiment as it is a need for a practical solution. I appreciate the feedback.

Tom

 

[shutterbug]

I watched it in slow motion. The tooth of the hook is slamming into the valley, and the motion of the gp continues, making it ride up on the next tooth and fall back into the valley for the second click. Maybe if you rounded the hook tooth at the point a little it would at least soften if not solve the issue. Go slow, a little at a time until you get satisfaction.

 

[TEACLOCKS]

The gathering pallet is lifting the rack too far, shorten the tip of the pallet, so the lock will fall right in to the valley of the rack.

 

[gleber]

The gathering pallet is lifting the rack too far, shorten the tip of the pallet, so the lock will fall right in to the valley of the rack.

That would quiet the clack, but I don't see how it would dampen the click. As I mentioned, I would also be concerned about the rack not moving far enough for the rack hook tooth to drop behind the rack tooth. There is some variation from tooth to tooth on the rack, so the gathering pallet needs to make sure it pushes the rack far enough for every tooth.

Another idea might be to change the shape of the rack hook tooth, so its tip doesn't land hard in the valley, but sort of slides down the rack hook teeth. I don't know the required geometry, but may try to sketch something to see if that is possible.

Tom

 

[Uhralt]

so its tip doesn't land hard in the valley, but sort of slides down

Did you try the viscous oil trick? That should make the landing softer.

Uhralt

 

[gleber]

No, but that's a thought too. Do you recommend any particular weight?

Tom

 

[Uhralt]

No, but that's a thought too. Do you recommend any particular weight?

Tom

Very viscous, like for a manual transmission (SAE 90?). You might even try a grease like main spring grease. It will probably stay better put. The choice depends on how heavy the lever is. It still needs to fall in time to catch the rack, but slow enough to hit less hard and a bit later.

Uhralt

 

[Bruce Alexander]

Maybe if you rounded the hook tooth at the point a little it would at least soften if not solve the issue

I think this would work. You'd just need to duplicate the profile achieved when you placed tape over the hook. There's plenty of material there so if you're very conservative and methodical I don't think you'll be doing irreversible damage to the movement. In "dressing" the rack hook, you may even be compensating for wear.