What's new
What's new

UPDATE on Things related to Vibration Stress relief on Straight-edges.

Status
Not open for further replies.

Richard King

Diamond
Joined
Jul 12, 2005
Location
Cottage Grove, MN 55016
Just want everyone to know the news. I have volunteered to send 10 HK-24" ground and scraped brand new casting for the tests. It my not happen as fast as I would like it to. To prove what I believe happens when one scrapes new and older straight-edges. The initial plan is to have a graduate student hang 10 straight-edges and ring 5 while scraping and test 5 that are not rung.

DR. Slocum wrote: "cast and then heat treated (stress relieve ) is well known. vibration stress relieve is also known…. the “new” question I think is after you scrape are there stresses? is that the question, that cause warping (or those stresses relax with time causing warp?)

but do not send anything until a project defined and I have a student

this actually would be a far betetr thing to do at NIST which has the measurement facilities.

Professor Slocum has contacted NIST. We have not heard back yet.

These tests should quiet those who doubt my teachings. I love challenges and I follow up on what I say and don't just make noise and disappear.

Also Assistant Professor who took my Boston Glass a couple of years ago and scraped one of my HKA-18 straight-edge in the class did some tests after the class as shown in his article. I had not seen this info and I mentioned his tests would have been better if he had supported the SE on the Airy Points. He said when I come out to help they will retest it and see what happens. See his article below.

I intend to travel to MIT or NIST to help assist in these tests. I expect the conclusion of these tests will be published for future generations to see how an old method we professional and hobbyist scrapers use to vibrate during scraping by hitting a casting with a soft blow hammer to remove any stress during the scraping process or while a SE or cast Iron parts is stored improperly or stressed in some way.


I also intend to ask them to test thermal tests when one holds with your bare hand on cast iron bars. We had a discussion on this a few years ago. Rich

file:///C:/Users/richa/Downloads/StraightedgeCharReport%20(1).pdf

PS: I emailed Professor Bell and he said that the tests were not on his 55PPI scraped straight-edge. He had an undergrad scrape on it and apologized it was not as accurate as he wanted when the tests were made.

Pic's are students "ringing" SE's they are scraping during classes One at Kieth Ruckers and one at Bourn & Koch.
also casting of SE's we plan on sending to MIT or NIST.
 

Attachments

  • 20170514_100542.jpg
    20170514_100542.jpg
    99.3 KB · Views: 313
  • 20180613_170125.jpg
    20180613_170125.jpg
    95.7 KB · Views: 301
  • 20180315_101434.jpg
    20180315_101434.jpg
    99.9 KB · Views: 296
Last edited:
I'd think they'd want to measure both the force and the number of "rings" -- maybe a transducer at the end of the hammer rather than as pictured? My own WAG is that it would take some considerable force to displace atoms in the cast iron and thus relieve stress -- and below some threshold it wouldn't do much. Is that (instrumenting the force) what's planned?

Might add that (again a WAG) that thermal cycling could put more force into a casting, than knocking it with a soft hammer while freely suspended. Is there some other suspected stress-relieving or stress-evening mechanism for ringing at some resonant frequency?

Sorry if this has been covered before -- I missed what preceded this update.
 
Please take a photo of the blueing on the plate with two prints side by side on it one before and one after ringing
 
Sounds like a good plan Richard - be wonderful if they could take some video footage for the YouTube community as well. I think it fair to say we are not all into reading papers on such results.
Still hanging & banging my SE selection as I work through them.
Mat
 
Please take a photo of the blueing on the plate with two prints side by side on it one before and one after ringing

Indeed, pre and post prints would be interesting. And you'd hope that at a research facility CMM mapping pre and post ringing would be done to provide quantitative data.

Getting some measured data is a very good idea. Measuring the response of several similar SE's, if practical, would be even better.

Denis.
 
Just to throw a wrench into things I think the real question is does "ringing" the straight edge produce a straight edge that is more accurate over time, not just does it effect the accuracy after "ringing". Perhaps it is that the act of "ringing" itself is what effects the stresses and changes the patterns seen more than that it released the stresses. It is like the standard chicken or egg question. :-)
 
Glad to see this being studied. And like BrianB's idea.

L7

Ps- you have a customer for 10 x 24" long straight edges?
 
Just to throw a wrench into things I think the real question is does "ringing" the straight edge produce a straight edge that is more accurate over time, not just does it effect the accuracy after "ringing". Perhaps it is that the act of "ringing" itself is what effects the stresses and changes the patterns seen more than that it released the stresses. It is like the standard chicken or egg question. :-)

I learned to do this from my Father and I am guessing he used it from his Journeyman he Apprenticed under. The way I would describe it is it is a short cut when scraping parts that have stresses in them, weather it be a straight-edge or a machine part like a lathe saddle that was crashed. You hit it as you scrape it and it releases the stress in it. One of our members Dee wrote of in the other thread that during a class he took like you did Brian he was scraping an old surface plate with a low middle and after I saw it I said "ring" it and he did and it changed the error in 1/2. Also in the link I have in the other thread (I will attach it) Jan S and Stephan G in the Denmark class saw how a 48" Camel Back changed. I suggest those who doubt this they can try it with bluing on their SE's.

Other thread that started this. I start talking about it on post 26.
https://www.practicalmachinist.com/...o-suitable-referance-start-351437/index2.html

I was also writing to another member who occasionally writes on here said he has used ringing when he rebuilds spindles that have been out of the machine when he assembles them with new bearings. It could be called a safety. Better safe then sorry. My Dad used to teach me that if you have dropped a Straight-edge, scraping a new one or find one that wasn't stored right it has built up stress in it and the ringing "relaxes" it.

I have been seeing it work for years. They change tenths at a time and eventually it stops moving.

I had written another post last night on my PC and in the middle of the night I was looking at my cell phone and some fricking way I erased it. I was responding to some of the other's who seem to troll my writings and always doubt what I teach. Their claim to fame is they prebuilt their wood lathe or Rung-fo, so they figure they are experts and some fools think they know what they are talking about!!!. I volunteer on here trying to improve my trade and like helping you and pass on my knowledge. To those pricks who never can say anything nice, who are always trying to prove to everyone on here they know something in this industry, those pricks, you know who I am talking about, why not STFUP if you can't be nice. We got rid on one longtime prick thank God!. I would give away or donate 50 castings if it would shut them the hell up.

I am putting up after the pricks called me out.

On a positive note: I am have written and asked my longtime friend Professor Alex Slocum of MIT and he wrote back 2 times. Once in this post and one in the other. PLus in this post his assistant teacher Julian who took the Boston class and I donated the HKA-18 straight edge he scraped and tested in his article.

So to the naysayers who are always almost "fake news" lets give them a chance and lets over time try to keep this thread free of you BS trying to be cute posts. If you can't say something nice to contribute with what your asking. Prove or disprove. Why not shop the hell up and go play with your toys and other things that make you happy. If anyone wants to send me some idea's or questions to ask MIT or Nist, I will catalog them and when we start the trials or tests I will send them to the Doctor PHD's in Engineering at MIT & Nist! Rich
 
Hi Richard,
Thanks for doing it! I really appreciate it and look forward to the results.
What I guess they will be doing is attaching sensors to the straightedges to record the force of the blows, rather than building a "blowing machine" which would hit them exactly the same.
I do research as my daily job and I know how experiments can balloon out of control if you keep adding controls and expanding the scope. However, it would likely be interesting to include in the test at least a couple of castings that haven't been heat treated.
My hunch is that, when you have too much internal stress, the ringing as commonly done is not enough to relieve it (i.e. you would continue to see changes, and not tapering down). And I suspect that this is indeed what causes so much skepticism around vibration stress relieving.

I'm really looking forward to the results.

Thanks!

Paolo
 
My take on the issue.

If you took three pieces of steel. say 1" X12" long 1/4" thick, two of them are plain mild steel (MS) the other a leaf spring (LS) shaped like a car spring.

Sandwich the leaf spring in the middle and bolt them together and you have a single piece of steel with an internal stress.

Now your piece of steel will not be flat, the LS will have tried to move back to it's relaxed position but the MS bars are stopping it. It will have deflected them some what though. Lets say it has not deflected them beyond their yield point.

So then we mill and grind the piece of steel back to flat, but the internal stress is still there.

What will the result be from doing various things to the steel.

If we ring it and it moves, will that mean the MS plates have somehow been weakened and have yielded to the tension of the LS?

If the piece of steel is under such tension does that mean small amounts of force will create movement, that otherwise would not as the steel is already under tension. Essentially do stresses result in a linear movement to stress applied or is it a non linear movement.

This could explain why some people say some straight edges seem really touchy to added heat from handling. The straight edge is under that such internal stress, just a little bit of extra energy makes it move a mile.

Could also explain ringing. However I think ringing to make any permanent changes, the material would need to me stressed beyond it's yield point. (that it the point of permanent deformation)
 
Well, if we're going through this effort maybe I can offer Alex a little help (I'm down there every Sunday). I'd like to add a few castings that get "high energy" vibration relief, as from a large transducer, adapted speaker coil, or high-speed eccentric on an electric motor.

I would think a "hard coupled" (bolted on) method would be most effective, no idea of frequency, amplitude, or duration to shoot for. Maybe a little more reading to see whatever the folks advertising the service have to say will help.

Richard, what say you? Can you spare a couple more castings? I presume you're getting them all back...
 
Sure....Alex noted that many experiments are funded. I was thinking we could do a "go fund me account"

I just had an order of about 5 grand that included 4 HK-24. Next time I have to order some more popular HKA-18 or HKA-12S I will order 12 more HK-24's. I was thinking it would be nice to experiment with a raw casting . Might have to mill some flats spots for the indicators to rest on the same places. Do a sequence of the same exact tests over and over. Maybe have to attach some flats so it is always sitting on the exact place. on Raw, High temp stress relieved, machined, ground, scraped. Then drop one on concrete and measure it, ring it, etc. WE could test dura bar, B&S straight-edges, etc.

You know in all my life I have never had so much interest in Straight-edges. Crazy as it may seem, I have never had anyone question ringing. I have had issues with air pockets or hard spots in them. Nothing is perfect. I don't care to spend a lotof time out there as a hotel is a bit $$ in DC or Boston. Alex said once I could camp out at his place....lol If I do hopefully he has a nice comfortable air mattress. lol

Thanks for the help my friends....nice is nice and this makes it fun to volunteer here and not have to argue with some of the #$&#@'s. LOL.....I am down in MO and it's already 85F at 6:00 AM. Sold my cabin and am removing our personal property before closing on Monday. Suppose to be over 105 F today and tomorrow...yuck.. Stay safe everyone. Rich

Here is DR Slocum.
Interview with Alex Slocum - YouTube

Have a few hours....lol Love his drill press...lol and his funky shirts :-)

2 75 Topic 1: Design is a Process - YouTube
 
or find one that wasn't stored right it has built up stress in it and the ringing "relaxes" it.
Rich
I've read this many times and from different people
So to be clear the premise is that a piece of iron will permanently deform under its own weight.
Even though it's no where near its yield point ?
I would like to test this I have a piece of good american lathe bed that I could use
My thought is basically bolt one end to the wall and hang some weights on the other I would machine in a way to measure the deflection does this sound reasonable? Has this been done before?
 
I've read this many times and from different people
So to be clear the premise is that a piece of iron will permanently deform under its own weight.
Even though it's no where near its yield point ?
I would like to test this I have a piece of good american lathe bed that I could use
My thought is basically bolt one end to the wall and hang some weights on the other I would machine in a way to measure the deflection does this sound reasonable? Has this been done before?

Why do you insist on re-inventing the wheel. Of course CI will permanently deform under its own weight. Ask any crankshaft guy or read the factory recommendations of lathe makers over the years.
 
I agree that cranks and lathe beds change in use
I have a hard time believing that they FLOW like a liquid when no external action is present except gravity and there not loaded to yield
 
"After you scrape, are there stresses?"

After you scrape, your SE will have new resonance characteristics, if ever so slight. Frequencies and locations of nodes and anti-nodes will have shifted. Is there measurable harmonic displacement in the SE's at rest state?
 
Also Assistant Professor who took my Boston Glass a couple of years ago and scraped one of my HKA-18 straight-edge in the class did some tests after the class as shown in his article. I had not seen this info and I mentioned his tests would have been better if he had supported the SE on the Airy Points. He said when I come out to help they will retest it and see what happens. See his article below.


If you're telling an academic where to support a straight edge, tell him to support it on the Bessel points, not the Airy points. You'll get extra kudos for that little difference*.


* The Airy points are the ones that cause a uniform beam to have its far ends horizontal. This is important in length standards.

The Bessel points give the minimum deviation from a straight line, which is what a straight edge needs.

There's bugger all difference between them for us mortals, even more so when you aren't talking about a uniform beam, but those guys tend to like mathematics. :D
 
I teach 30% in from both ends, but said Airy for you brain-E-ac's....LOL Working on machine tools here not the metric bar that Moore talks about. I had a friend, PHD named Richard (Dick) Viznor and told me once if you have a square casting you use .707 x Length divided by 2 to set a machine or part on. He called it the "rotation of points" too. He said machine rebuilders working outside the lab can use 30% on Rectangular shaped parts.

30 years ago after the Monday Morning class at John Deere in Waterloo, IA I taught that to the class and at break one of the students pointed out a Cone-a-matic screw machine had 4 leveling pads the measured exactly at the .707 x L divided by 2 locations. When I set a Milling machine table on 3 points I use 30% in from the ends. Never had a problem. I have found after teaching all these years 30% works. Might not be scientifically proven, but it is "work" proven by me and all my students. Rich
 
Last edited:
Status
Not open for further replies.








 
Back
Top