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Ulma Doctor, Scraping Mentor

The Liberal Arts Garage

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#32
Just a partical from an "old Engine Guy"........after the bloc, casing, cover,or other
part was chipped, scraped , sandblasted, or whatever,it was primed and dumped
in the backyard for a few months to "settle down"before machining; and that is why
those ancient parts you are refurbishing are painted even in utterly inaccessible
corners. ..........BLJHB
 

expressline99

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#34
I was reading the other night on about cast iron stress relief on certain grades needing temperatures to be brought up to 1500 degrees then down to 1000 slowly... after which keeping it there for sometime before slowly bringing it down to room temps. If they are suggesting it takes that much heat to do this how would such low temperature changes of outside weather make enough difference? Maybe a hundred degrees max over a year? Most swings being 20-30 degrees per day? I know Bridgeport and I believe south bend did a similar "outdoor" approach. I just wonder if there are any supporting cases of machining the same product after a normal cool down period vs. a few months or a year outside? Same batch castings of course.

Paul
 

Bob Korves

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#35
I was reading the other night on about cast iron stress relief on certain grades needing temperatures to be brought up to 1500 degrees then down to 1000 slowly... after which keeping it there for sometime before slowly bringing it down to room temps. If they are suggesting it takes that much heat to do this how would such low temperature changes of outside weather make enough difference? Maybe a hundred degrees max over a year? Most swings being 20-30 degrees per day? I know Bridgeport and I believe south bend did a similar "outdoor" approach. I just wonder if there are any supporting cases of machining the same product after a normal cool down period vs. a few months or a year outside? Same batch castings of course.

Paul
I think it is an issue of time, and one of settling. Something in a stressed condition wants to move toward relieving that stress. Time can and will do that. The molecules of metal will subtly shift in the matrix toward a less stressed condition. It is always moving 'toward' the low stress condition, never actually reaching it completely. We would like to hurry the process up. Heating it to 1500 degrees will let the stresses out, but some new ones will form as it cools. In the production and use of metals, a lot of time and energy goes into relieving stresses. Some of it is science, some of it is pragmatic (whatever seems to work best.) If you brought the subject up at a place like a foundry workers or steel mill workers convention you could probably raise a 'heated' discussion...
 

Bamban

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#37
Hi Nez,
i'd love to come back down to Austin and San Antonio, it's been a long time.
I'd be proud to show y'all what i have learned!!
At the Rongero Inn "we'll leave the lights on for you" And I will stock up on San Miguel beer.

We'll make this little jewel near perfect. Do you remember it passing through Ulma Doctor's shop for certification?
20170302_003817.jpg
 
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Vacuum

Iron
Registered Member
#38
Then there is cryogenic treatment process as further help to get castings, or just about anything to remove stress.
I hope I am allowed to put in a link here. At http://www.cryotron.com/index.html under the solutions tab are three articles, Cryogenic Stress Relief, Wear Solutions, Thermal Stresses in Castings, that provide some information. They gear it to automotive type products but reference other industries.
I have experimented with cryogenic treatment using styrofoam containers and dry ice. I think it worked for me. Time will tell.
Also striking metal with any instrument is a form of shot peening another form of stress relief.
 

Turnaround

Iron
Registered Member
#41
Is that a fluorescent light mounted high on the lathe? I thought those bulbs would freeze the work image at sixty cycles, and possibly lead one to grab a spinning piece of work. I thought one always had an old timey light bulb shining on the work to prevent such visual freezing of moving parts of equipment? Don't know, but that is what I thought.


Sent from my iPhone using Tapatalk
 

Dabbler

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#42
You are right, we used to have ikea desk lamps over each of our lathes to help that. Now many LED bulbs have full wave rectifiers to somewhat smooth out light output. There are also halogen and other filament bulbs available if that is not enough.
 

Bamban

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#43
Are you gents talking about the light up at the top? That is an automotive flood light. If you are talking about the 4 ft light, that is a LED at the lower wave length. 20170302_003756.jpg
 
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Bamban

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#45
I'm overly curious about what you have mounted at the head stock?
Paul
Paul,

That vertical piece? That is just a SS barrels drop, I was going to use it to mount the control box on. Now, I use the bore to store a short cleaning rod and a bore brush at the ens I use in conjunction with cleaning patch to swab the chamber in between running the finishing reamer.
 
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expressline99

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#46
That


Paul,

That vertical piece? That is just a SS barrels drop, I was going to use it to mount the control box on. Now, I use the bore to store a short cleaning rod and a bore brush at the ens I use in conjunction with cleaning patch to swab the chamber in between running the finishing reamer.
I actually didn't see that till you pointed it out. :confused 3: I meant the thing mounted on the spindle with all the set screws in it?
 

Bamban

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#47
20170128_140539.jpg 20161210_231941.jpg 20161214_174702.jpg
I actually didn't see that till you pointed it out. :confused 3: I meant the thing mounted on the spindle with all the set screws in it?
Sorry, that is my spider chuck used when chambering barrels. The 4 set screws are the actual adjusters and the 8 socket heads are used to provide additional clamping on the barrel. The 4 cup point set screws are sort of like your 4 jaws, here are a couple of picture to show you how the system is used, one showing the initial set up and how the barrel blank is clamped, the other picture after the chamber has been cut with the barrel extension screwed on. The bolt sticking closed on the Go Gauge. The 3rd picture shows a barrel set up for crowning. Notice the cup point set screws are torquing against the ball bearings while the aluminium finger clamps are the ones actually clamping on the barrel. The ball bearings allow the barrel to gimbal when using the rear spider during fine tuning of the barrel bore.
 
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chips&more

Active User
Active Member
#49
my previous point , whether taken or not, was that most anything can be scraped to varying levels of precision
whether the material will hold the tolerance or not is inconsequential when you are explaining and showing scraping to someone who has never held a scraper before.
I scraped my finger (skin) the other day. But how do I check it for flatness?
 

bfd

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#51
lookin at your lathe picture reminds me of the guy at work that used to put an indicator on the first indicator to make sure it didn't move and then put one on the second one to make sure it didn't move and so on until you run out of room Just kidding nice lathe bill