Touching steel with fingers

[Anachronist58]

One might think that I have already blabbed on this enough, but after further study, I want to tighten up a couple of Items.

 

The most pernicious hazards of Chlorinated Solvents appear to produced by exposure to Ultraviolet light from Arc Welding. Phosgene Gas gives off "the pleasant odor of newly mowed hay".  Let's just take it for granted that Chlorine and Fire is a Red Flag.

 

Hot Filing and Oil:  I recall a batch of improperly degreased aircraft hydraulic pistons went into the oven 300~350 Deg F "must bake after grind"  cycle. Components of the oil diffused into the metal (stained it) Turned out to be an unacceptable condition. Don't remember whether we lost or saved that batch, but the stain was locked into the metal.

 

What think you, Heat Treaters? Might this make Oily Hot-Filing a No-No?

[Stephen Olivo]

Usually the amount of oil that is left on my hot rasp/file is such a thin coating that it offers no real danger during hot filing minus a possible small amount of smoke.  The oil left on tongs during my heat treating steps just gets almost constantly burned off/on to the tongs as I hold or put the next piece into the forge.  Using it to cool punches can be interesting as it flash fires often as you place it on the metal/in the hole.  Usually though it is only enough to burn for half a second and then it goes out so I have never found it to be more than just something to take into account when you work with it.  Sometimes I have a oil rag handy to wipe the punch against so the amount of oil is gone before it creates any sort of flame.  

[Nick]

I was drawfiling a large piece recently and it reminded me of this thread (hence the thread necromancy).  It was the first time I had really draw filed anything to this degree but the project called for it.  The first file I used was a brand new flat bastard.  I had already ground and filed the surface pretty smooth, and there was a spot I had run my finger along.  I really could feel the file run along that spot, not skip but certainly not cut as much, and after a few passes there was a black residue built up in the file marks in that spot.  So I cleaned it up and wiped it down every time I touched it to check for irregularities.  I don't have acidic skin but I was certainly sweating at that point.  I kept an eye on it after that.

[L Smith]

This is how I got my first job The company owner (an inventor) had me handle an air bearing then told me to come back in a week. He looked over the air bearing and said YOU ARE HIRED  your fingers don't stain metal. It has always surprised me how many people stain metal.

[mitch4ging]

This shows up with guitar players. Some have to change strings quite often because of their skin type, others can play on a set of strings for a long time before getting too corroded.

[Frank Turley]

I worked with an older man, Victor Vera, who was brought up in his father's and uncle's smithy in San Luis Potosi, Mexico. He was taught to never touch a file or it would ruin it. No explanation given. Yet I just met a retired shop teacher after 30 years teaching, who swore by using Tapmatic Gold cutting fluid for all room temp filing. I'm going to give it a try.

 

In Albuquerque, Peter Ross was asked why the "flattened peen." He said, "It spreads metal and there's less clean-up." By clean-up, I think he was referring to the steel's surface smoothness compared to using a half-round section peen.

[anvil]

all my crosspeen s are flat faced because it moves material faster.

I believe this is so because there is more material directly under the flat that moves material outboard than a rounded peen.

if you think about it on a rounded peen there is only a thin line that contacts the material where the forces are completely directed down. all other places on the curve of the peen forces are split between down and to some degree pushing out and up depending on the curve profile.

thank you Francis Whitaker for this.

concerning cold shuts(shunts) these happen in many ways other than a forgeweld.

1: after splitting the tines on a fork with a chisel the center can close up causing a cold shut and weak point

2: the inside radius on a forged right angle bend can cause a cold shut if there is no radius. this then becomes a weak point.

[george m.]

I always thought that a cold shut/shunt was a fold in the surface of a forged or rolled piece caused by adjacent blows/pressure spreading metal towards each other and forming a sort of trench or fold which gets pressed into the metal.  At one point in my misspent youth I was an inspector at the Alloy Bar Mill at US Steel's South Works in Chicago and had to look for shuts in the rods and bars before they were shipped.  If I found one I hit it with a grinder and if it was too deep the bar was rejected and sent back to be used as scrap.

[anvil]

George, that's correct although included in your definition is that end piece in a forge weld that doesn't quite go away.