There was a failed startup that was developing a then dramatic high speed process that failed largely because the design had an absurdly high rbb which they thought would not matter.
I think there are versions of process simulators available but good luck getting the parameters. At some point a distributed model is more accurate and you would need a well calibrated S-parameter setup and the right software to extract it. IME this is prone to lots of errors.
I am aware of them. Actually not a bad idea for tha gear I was trying to make. Turning the clock over in a day or two, but do have the spare regulator I cannibalized to get the gear, so could easily try again. It would be handy should the museum get a cuckoo with a chime set and a broken nylon gear.
I had purchased several types of plastic, including delrin for this gear. Also considered using brass to make it more robust, the nylon lasted only 50 years.
In fixing a music box weeks before I found that the coefficient of friction of brass on stainless to be too high for the geometry. The music box regulators have a reversed worm gear, where the wheel drives a worm. While the worm pitch is very loose, dry brass will not reliably turn it. Nylon does. So, if I go brass, it requires lubrication. That is why I had to fix it in the first place, the organic oil had gummed up. Where's Howie when I need him?? I used a 10 weight synthetic.
That said, I didn't try the delrin, as I didn't know if it's friction coefficient against SS was low enough. Besides, I wanted to move on.
I may have to try making a metal shaper, this gear and the forces involved may be low enough for finger ops as you said.
Wish we had this discussion two months ago.
jn
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Oh, yes, there is wrong.
... When you play a source which you know the least details and that do not sound at all as expected. I'm not speaking about something as subtil as distortions levels at <-90dB, but the essence: Size and presence of the instruments in a scene that we can accept as it is. Overall balance.
The fact that so many people marvel at the "definition" of these speakers is, from my point of view, revealing their low exigency and knowledge of how instruments are supposed to sound in a good system. The fact that those speakers are detailed in the high of the spectrum and the low basses, and not at all in the low medium makes the things worse than if it was not detailed ... everywhere.
This said, after a day+ night of burn-in, real improvement. And it is not because I got used to these: I had not put the feet in the room during all this time. Let's see what will happens with a added sub.
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I am still on a steep learning curve. The 7 by 16 mini lathe is 6 months old.
I hold the cutter in the headstock spindle, use the slides with dro's to position the indexing fixture.
I wasn't too sure about going off plastic. The gear is press fit onto a shaft, roughly 63 mils diameter, figuring 1 or 2 mils interference but worried about having the plastic crack (that is what the old one did).
And yes, I can still count to 10..
No, never heard of it. I'll have to google it.
thanks,
John
50? years and Delrin gears is the sorry fate of the otherwise fine HP8640 tuned cavity signal generators. There is some Italian ham who makes replacement gears from brass.
regards,
Gerhard
Interesting find George. To be fair, Fs first goes down after burn in. But that it goes up again after hundreds of hours, that is surprising. What material is the surround made of?
JN
Put the gear blank in the live chuck. Power off put the bit in the tool holder. Attach an index gizmo also to the chucked blank. Now do a very shallow cut by scraping the tool past the blank. Rotate the head one tooth pitch and repeat. After all the teeth have been scraped once, increase the depth and do it again. Makes a lathe into a shaper. Motor power is not used.
Put the gear blank in the live chuck. Power off put the bit in the tool holder. Attach an index gizmo also to the chucked blank. Now do a very shallow cut by scraping the tool past the blank. Rotate the head one tooth pitch and repeat. After all the teeth have been scraped once, increase the depth and do it again. Makes a lathe into a shaper. Motor power is not used.
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You rang??
With most metal-to-metal interactions the oxide film is far harder than the underlying metal and provides some friction reduction at low loadings. Some stainless steels have very thin oxide layers (often monoatomic) which consist of oxidized nickel and chrome. They provide excellent chemical protection for the underlying metal, but being so thin they provide very little hardness or surface stiffness. As a result, the underlying metal can physically deform and interact when loaded.
There is a well-developed technique called friction welding, where surfaces are pressed together while being moved against each other. The resulting friction achieves several goals: it breaks through oxide films and causes enough friction to melt and weld the metals together. A very similar phenomenon occurs on a much smaller scale when any two surfaces are rubbed together: since they are not perfectly flat, the pressure is concentrated on the microscopic asperities (peaks) which then do indeed atomically interact, what some may call molecularly bond...this is called friction...(oh Mr. Friction)
This principle is also why merely coating the surface of a sticky metal such as copper or stainless with Dykem or even a Sharpie will improve it's machinability. Uncoated, the evolving chip bonds to the base metal and cutter, tearing out chunks of metal and giving high frictional force to the cutting. With the Dykem, the thin organic film interferes with this bond, allowing for clean chip removal.
When designing parts to be loaded against stainless, it seems to be common to use powder metallurgy materials such as oil-loaded bronze (Oilite) or iron. When loaded these form a self-refreshing lubricant film. I have purchased them dry, heated them up and immersed them and immersed them in the appropriate lubricant. Upon cooling they further pull in the oil. Further impregnation can be achieved by vacuuming them afterward.
It is indeed a cool subject, I have a 5hp 2-axis CNC knee mill here and am often surprised at how poorly (or well) different material act under loading with cutters...choosing the proper surface speed and lubricant is a well-defined science, and a lot of the older machinists develop a superb sense of how to machine different materials at maximum speed with excellent surface finishes...me, I'm still a hack after 40 years of intermittent trying...
Cheers!
Howie
This is called broaching, and it is often used to form gear teeth...as well as keyways and square holes in metal...one of it's biggest advantages is the ability to use extremely slow surface speeds and limit heating of the base metal or sticking of chips...it can give really fine surface finishes.
Full disclosure: I'm not a professional machinist. I worked in a shop part-time as a youth which lit my interest in metalworking, but I was hired because I was a radio amateur and knew how to fix and maintain the induction brazing machine which was a 20 KW 27 MHz power supply feeding water-cooled copper tubing induction coils. I also had to maintain the mercury rectifiers in the electromagnetic chucks around the shop. Much later as an engineer at a media plant we had the luxury of a fully-equipped machine shop with 8 full-time professional machinists which I took full advantage of. A good machinist has in-depth knowledge of metal alloys, characteristics and proper working methods which are amazing!
Howie
Some claimed that the local G was that far off due to enormous non-uniformity of local geology. I still think it was mirrors, etc.
Scott do you remember a show call Believe It or Not. There was episode that claimed there were spots on earth were gravity is wacky. You can stand thing up that normally are difficult to balance. Like pencils and broom sticks.
I was too young and didn't have the resources at the time to follow up on the claims made on that show. Your post reminded me of that.
There is a common standard in hi-fi when it comes to audio replaying electronically. What you are referring to is personal-fi as in what the listener prefers.
You just confirmed your own post about personal-fi. "as expected" is a personal view.
Anything on how instruments are supposed to sound in live performance?
That's not an objective comparison.
Notice the use of Scare quotes - Wikipedia. T, JC and MH use them on a regular basis when they use vague subjective terms, I suspect the reason is to muddy the waters and shut down argument.
Spider is impregnated cloth. Cone surround is rubber.
On larger 10”-12”drivers with impregnated cloth surround I have noticed a drop of Fr around 10% with a few days exercise but I haven’t made a follow up survey along time to see if Fr recovers.
Close.
Today, official g measurements (treaceable to int. stds) are conducted with instruments like these in the 1st link (suspension resonance period >>100sec ala LaCoste zero length spring)
http://microglacoste.com/wp-content/uploads/2017/03/Brochure-A10.pdf
Gravimeter - Wikipedia
George
Dave Thomas is one of the most brilliant people in the music world, I love in an interview when asked why he was not active in social causes, he replied: "The dancer is puppet to the dance, in order to see clearly the solution is to stand still."
I like better still his description of what all of the cell phones, internet, etc has done to society: "Everyone now inhabits their own personal ghost town." It is true. With all of these metadata accepted as reality instead of the events and things themselves, they are just static, ghosts in our heads, separate from all the other ghost towns in other's heads...ghost town indeed.
Now what were we discussing again? The art of fooling ourselves into thinking air vibrating in a closed room is the same as the actual event?
It's too early to get drunk...anyway I need to go fix a barn door, it looks like a bear beat it up to get at the grain...
Howie
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