# Ulma Doctor, Scraping Mentor



## Bob Korves (Feb 22, 2015)

A couple weeks ago I saw Mike Walton's (Ulma Doctor) request on HM for people interested in a scraping party and sent him an email saying hell yes, I am interested!  Mike got back to me and said that there wasn't much interest in the scraping party, but perhaps I could come down to his shop and do some one on one, hands-on training.  He didn't need to ask twice...

We were able to get together today and I thought others might be interested in what kinds of things we were doing there.  

First, Mike showed me around his shop.  I lost count of machines after about 4 mills and maybe 6 lathes, along with a lot of other cool stuff.  In Mike's defense, in case his wife sees this, some of the lathes and mills were small ones.  And I thought I had it bad.     8^)

Next, we got started on scraping.  Mike showed me all the tools of the trade he had and described their usage.  We put some spotting dye on a surface plate, and rolled it out.  Then he marked up our first victim, the bottom of a old V-block that had seen better days.  

After reading the spots together Mike showed me how to use the Biax power scraper to work the surface, then stoned it and cleaned it.  And then we started on the next pass.  This time it was MY turn to hold the weapon with MY finger on the trigger.  It was, quite simply, no big deal.  The Biax tool is well behaved, pretty easy to hold on to and to control scraping of the work, even for this raw beginner.  It is also quite productive with experienced hands on it.

We rinsed, lathered, and repeated until the V-block was flat and had quite a few points, with only the corners needing more work.

Then we moved to hand scraping with several different tools.  For a victim this time I was using the Harbor Freight plane that Mike had purchased new for about $8 and had worked the bottom of it to a very nice surface.  I got to work on one of the sides of that plane and worked it through quite a few scraping cycles with Mike keeping an eye on me while working his own projects.  Above is a pic of it after my last pass.  There is a smudge on it from my thumb, and the extreme front has no spots because the plane has a very low area there that I was not able to get completely scraped level in the allotted time.  It is in no way finished but is well on its way for Mike to complete.

Scraping is a mellow, zen like activity.  Go through the cycles, read the spots, interpret them, and improve the work as much as you can while making very shallow cuts where indicated.  Repeat, repeat, and keep on repeating.  The progress is visible and rewarding.  When the work is becoming quite flat it feels different, and slides on the surface plate like wet glass.  It is not instant gratification, which can be a good thing.

Mike is a quite capable instructor, friendly, easy going, happy, and glad to be doing and helping.  Helluva nice guy, too.  I'm planning to go back for more real soon.
-Bob


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## Ulma Doctor (Feb 22, 2015)

I'm glad you had a good time and that i was able to help you along.
you really did get the ideas fast and were doing things like you have done it for years.
thanks Bob it was a pleasure have you in my shop- you are welcome here anytime.

for everyone else...
the credit for this side's scraping of the plane is all Bob's.
i knocked the ridges off the long end an old 18" file i had in the shop and ground it to do the hand scraping.
even with the 5* rake sharpened file he did excellent work.
almost anyone can scrape using modest tools and a flat rock.


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## MARVIN GARDENS (Apr 2, 2015)

I'd sure like to attend your next "party."  I have never done any scraping or even seen it done.

I'd did pick up what look like an unused set of four Mound scrapers for $20 at a local flea market.

Regards.

Bob


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## expressline99 (Mar 13, 2017)

Did you guys ever repeat this?


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## Ulma Doctor (Mar 13, 2017)

Hi expressline99,
on Feb 12, 2017 we had a meeting of some local members at my house.
i held an informal class for the group.
Bob Korves brought a piece of mild steel he had flattened on his newly acquired surface grinder and the piece was then scraped by the group.
everybody got a shot at it!
we had a great time!


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## expressline99 (Mar 13, 2017)

Ulma Doctor said:


> Hi expressline99,
> on Feb 12, 2017 we had a meeting of some local members at my house.
> i held an informal class for the group.
> Bob Korves brought a piece of mild steel he had flattened on his newly acquired surface grinder and the piece was then scraped by the group.
> ...



Sounds awesome. I'm just over the hill in Reno. So with some advanced notice I'd love to show up for meeting sometime. I can be the super novice of the
group.


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## Ulma Doctor (Mar 13, 2017)

I'm sure we could make room for another enthusiast


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## Kernbigo (Mar 13, 2017)

don't scrap steel it is not stable, the heat from you hand can change how it reads, use cast iron.


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## Ulma Doctor (Mar 13, 2017)

Just about Any solid metal can be scraped


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## Kernbigo (Mar 13, 2017)

why do you think they make straight edges out of cast iron, it is stable after you leave it out in the weather for a couple years to stabilize, than machine it and scrape it in .I did this for 30 years and trust me mild steal is not stable


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## Ulma Doctor (Mar 13, 2017)

For instructional purposes mild steel works just fine.
The piece being scraped was not for precision, merely a teaching aid.
The mild steel was used as a comparison of relative flatness achieved by a surface grinder vs. scraping
The surface grinder was flat to about .001"


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## Kernbigo (Mar 13, 2017)

you are wrong mild steel is not stable for scraping i tried it,  one time and the heat from your hands would change it, why arent surface plates and straight edges made of mild steel, because they are not stable


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## Ulma Doctor (Mar 13, 2017)

OK i'm wrong,


Hear Ye!!!!

Thou shalt never scrape mild steel, even if it is for instructional purposes that will never be used for a precision comparator or reference or facsimile thereof
cast iron will be the only material to ever be scraped from this moment forward!!!


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## 4GSR (Mar 13, 2017)

You wouldn't want a straight edge made from steel flat bar.  But I have scraped a many of gibs that were steel.  Believe me it will move all over the place on you, not easy to keep a steel gib straight from scraping.

Ken


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## Ulma Doctor (Mar 13, 2017)

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.


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## Rustrp (Mar 13, 2017)

Kernbigo said:


> you are wrong mild steel is not stable for scraping i tried it,  one time and the heat from your hands would change it, why arent surface plates and straight edges made of mild steel, because they are not stable



Perception changes as we educate ourselves. Things that may be dropped and bent tend to be made of cast iron or steel that can be tempered. This doesn't mean they can't be damaged, just more difficult to do. I'm just adding two bits here because I think it's unfortunate to get stuck in black and white thinking. It stops the educational process. Many items manufactured from cast iron years ago are now manufactured from steel plate. 

The sheetmetal working equipment I own is predominately made of steel that requires scraping to true them up. Should I not scrape them. I have a 10' shear with a bed fabricated from heavy steel plate. I've used many shears where the beds were made from cast iron. It's easy to lose sight of of the lesson being taught if we get tunnel vision on dimensional tolerances or mechanical properties of material. I don't have to be wrong for you to be correct. 

I encourage that education and experience be used in a positive manner. e.g. My youngest son came home from wood shop and said; Dad, most of the guys don't even know how to use a measuring tape. I said; Use what you know to help them learn. -Russ


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## Ulma Doctor (Mar 13, 2017)

my intention was to welcome others into my home and teach whoever would listen, what i was taught and have experienced in metal scraping.
i accomplished my goal


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## expressline99 (Mar 13, 2017)

and all I did was touch the old thread here...I swear I couldn't help myself.


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## bfd (Mar 15, 2017)

even cast iron moves with the addition of heat maybe not as much as other materials. when I was an apprentice I had to scrape the turbine cases of boiler feed pumps they were made of steel and were scraped to allow for sealing steam without any sealant between the faces. never had a leak. the large cast iron straight edges used for restoring lathe ways have wooden handles built in so the heat from holding them do not change them. bill


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## 4GSR (Mar 15, 2017)

I have a beveled cast iron straight edge dad made out of a section of lathe bed on a machine his company scrapped out back in the 1960's.  He never did stress relieve the piece of cast iron before scraping on it.  Still have it, it still moves around when you try to scrape on it.  One of these days, I'll get it stress relieved. But kid you not, cast iron does move on you if do not stabilized it first.  Ken


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## Bob Korves (Mar 15, 2017)

4gsr said:


> I have a beveled cast iron straight edge dad made out of a section of lathe bed on a machine his company scrapped out back in the 1960's.  He never did stress relieve the piece of cast iron before scraping on it.  Still have it, it still moves around when you try to scrape on it.  One of these days, I'll get it stress relieved. But kid you not, cast iron does move on you if do not stabilized it first.  Ken


Ken, hang the straightedge up by a rope or some wire.  Then ring it like a bell, multiple times and in different places, loudly.  It helps the cast iron to settle down.  Heat treating is also a good way to get the stresses out.  Doing both is best.


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## 4GSR (Mar 16, 2017)

Bob Korves said:


> Ken, hang the straightedge up by a rope or some wire.  Then ring it like a bell, multiple times and in different places, loudly.  It helps the cast iron to settle down.  Heat treating is also a good way to get the stresses out.  Doing both is best.


Bob,
I may try that, it's only about 16" long. Still work though.  I don't know how cheesy the material is , don't want it fall apart beating on it. 

Sent from my SAMSUNG-SM-G920A using Tapatalk


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## Bob Korves (Mar 16, 2017)

4gsr said:


> Bob,
> I may try that, it's only about 16" long. Still work though.  I don't know how cheesy the material is , don't want it fall apart beating on it.
> 
> Sent from my SAMSUNG-SM-G920A using Tapatalk


Don't beat on it, but give it some good rings, not tiny taps.  The more vibration the better.


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## Rustrp (Mar 16, 2017)

4gsr said:


> Bob,
> I may try that, it's only about 16" long. Still work though.  I don't know how cheesy the material is , don't want it fall apart beating on it.
> 
> Sent from my SAMSUNG-SM-G920A using Tapatalk



Without the instruments to measure VSR you'll need to go by sound or tone. It would be interesting to get some feedback on the tone and how it changes over a period of three or four different tap..tap...tapping sessions.


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## Bob Korves (Mar 16, 2017)

The other thing that gets metal to settle down is time.  Old time machine builders used to age their castings for months or years before machining them, with a heat treat in the middle, and sometimes age them again after rough machining to let them settle down.  Manufacturing was different then...

One of the amazing things for me as a new machinist was removing one face of a 1/4 x 2" cold rolled steel bar and then noticing the banana shape it had afterwards.  It ruined the part, but I sure learned something!


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## Rustrp (Mar 16, 2017)

Bob Korves said:


> The other thing that gets metal to settle down is time.  Old time machine builders used to age their castings for months or years before machining them, with a heat treat in the middle, and sometimes age them again after rough machining to let them settle down.  Manufacturing was different then...
> 
> One of the amazing things for me as a new machinist was removing one face of a 1/4 x 2" cold rolled steel bar and then noticing the banana shape it had afterwards.  It ruined the part, but I sure learned something!



Cold rolled bar is so misleading. What you see when you look at CR and HR bar would lead one to believe the CR would be the better choice to work. Dimensionally yes, but the induced stress due to cold working leads to many surprises especially the merchant quality we commonly use. The annealed and stress relieved product is much better to work with. The quality of the end product we use begins at the mill and how they treat, prep the ingot or billet before rolling or drawing.


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## 4GSR (Mar 16, 2017)

Bob Korves said:


> Don't beat on it, but give it some good rings, not tiny taps.  The more vibration the better.


I have a 42" straightedge I made from a piece of G-2 Dura Bar.  I hung it from the ceiling and took a rubber mallet started hitting it not real hard but just enough to get the vibration needed to do the stress relieving.  Surprisingly, it moved less than 0.002" in the entire length!  I was glad.  The piece of cast iron that I made that straight edge out of sat out in the South Texas heat for nearly 10 years before I machined on it.  And I do believe in seasoning cast iron in the sun for a couple of years too.


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## Rustrp (Mar 16, 2017)

This thread has taken an interesting twist (thanks Bob) from the original scraping topic to vibration stress relief VSR. Both are important because both are dealing with molecular realignment at different levels. 

This begs the question; What part did VSR play in the crack that developed in what we now refer to as the Liberty Bell? It was rung many times before the crack developed. Was there a major defect in the casting where the crack occured or just too much overall stress.


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## bfd (Mar 17, 2017)

ive heard that some time ago engine mfgs user to burry the castings in the ground to stress relieve the castings don't know if its true but it sounded good bill


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## Bamban (Mar 17, 2017)

Ulmadoc,

You need to take the show on the road, head East to CenTex. I believe I can round up a couple of guys to learn the art. KVT, would most likely drive up San Antonio to join the fun.

BBQ and Shiner is on me.


Nez


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## Ulma Doctor (Mar 17, 2017)

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!!


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## The Liberal Arts Garage (Mar 17, 2017)

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


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## kvt (Mar 17, 2017)

Yea,   I would drive up for that,   Between work, and stuff it would be a nice break.  
  Jut learning how would be nice. 
Then I would have a good reason to get more tools and stuff.


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## expressline99 (Mar 17, 2017)

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


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## Bob Korves (Mar 17, 2017)

expressline99 said:


> 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...


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## expressline99 (Mar 17, 2017)

It's very interesting to me. Odd how the stresses of molecules closely resemble the human condition!


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## Bamban (Mar 18, 2017)

Ulma Doctor said:


> 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?


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## Vacuum (Mar 18, 2017)

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.


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## Bob Korves (Mar 18, 2017)

Bamban said:


> 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?
> View attachment 229038


I saw that lathe at Mike's shop, Nez.  You have done a really nice rehab on it!


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## Ulma Doctor (Mar 18, 2017)

Bamban said:


> 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?
> View attachment 229038



you make a sweet deal Nez!


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## Turnaround (Mar 18, 2017)

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


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## Dabbler (Mar 19, 2017)

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.


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## Bamban (Mar 19, 2017)

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.


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## expressline99 (Mar 19, 2017)

Bamban said:


> 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 an LED at the lower wave length.
> 
> 
> 
> ...


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


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## Bamban (Mar 19, 2017)

expressline99 said:


> 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 (Mar 19, 2017)

Bamban said:


> That
> 
> 
> Paul,
> ...



I actually didn't see that till you pointed it out.  I meant the thing mounted on the spindle with all the set screws in it?


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## Bamban (Mar 20, 2017)

expressline99 said:


> I actually didn't see that till you pointed it out.  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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## expressline99 (Mar 20, 2017)

That chuck is great! Thanks for explaining it.


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## chips&more (Mar 20, 2017)

Ulma Doctor said:


> 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?


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## tertiaryjim (Mar 20, 2017)

Fingertips should use the eyeball as a master. I do it all the time.


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## bfd (Mar 31, 2017)

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


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## Bob Korves (Mar 31, 2017)

chips&more said:


> I scraped my finger (skin) the other day. But how do I check it for flatness?


If it looks flat enough to blue it in, go to the emergency room...


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