Touching steel with fingers

[billyO]

Hello all.  As I was filing the sharp edges off a combo tenon butcher/spring swage I was making out of 4140 before hardening, and running my fingers around it to make sure there were no sharp edges that would prevent cold shuts, I remembered hearing Peter Ross chastize Roy Underhill on an episode of The Woodwright's Shop  a number of years ago for touching a piece he was working on with his bare fingers, saying something to the effect of, "Blacksmiths NEVER touch bare metal with their fingers when filing".  Why?

[Steve Sells]

no clue.. I do all the time

[LastRonin]

Ever get a splinter? From my experience, metal shavings can be harder to remove. That is my guess as to why he may have said that.

[Francis Trez Cole]

the only reason I can thing of is the metal needs to be protected with a finish to help prevent rust. But Peter also said that a filed piece will not rust as fast as an un filed piece.

[DSW]

I wonder if that has to do with the fact a lot of work was hot filed. Metal at a black heat wouldn't look any different than a cold piece. Sounds like something generic you tell an apprentice who is just learning. I know in my 1st class we were always told to treat any metal on the floor as "hot" no matter what it looked like and never grab it by hand.

[Rich Hale]

" no sharp edges that would prevent cold shuts"

Really?

[Jim Coke]

Greetings Bill,

 

I took some classes with Peter and he is great for comments like that....  If I were to guess it would be the finger oil... Oil and files don't mix...  I once ask him why he had a flat pien on his hammer...   I got the look and he said ... '' Is there another way ? "  He is still one of the best smiths I ever met...  LIL grumpy but I learned to over look that ..  Oh well I have been told I'm grumpy too...

 

Forge on and make beautiful things

Jim

[Michael]

Roy DOES try to touch everything it seems.  A lot of the blacksmithing episodes are cringe worthy as he is just about to get burned or hit.

[Rich Hale]

Oil and files do not mix?..I oil all of my files on a semiregular basis......do not understand that statement.

[Jim Coke]

Rich ,

 

You are a fine blade smith and what you do is designed for what you do.... Peter is old school Williamsburg and most likely kept his files dry and free of oil..

That's my take... Just my 2c.

 

Jim

[billyO]

" no sharp edges that would prevent cold shuts"

Really?

Perhaps I should have said, "a crack", but yes, I basically meant what I wrote.  As you form a tenon on the end of a bar, if you don't radius the shoulder where the tenon meets the main stock of the bar, you're much more likely to forge in a crack.  Isn't that why we use a monkey tool to square up the shoulder instead of trying to make it square when we butcher the stock???

  I may be using the term cold shut incorrectly, but that was what I was taught.  (but age can make memory less accurate....)

[Steve Sells]

Cold shunt is a bad weld.  I dont know how making sharp edges can prevent them either.  We  dont so much forge in a crack, as get stress risers form the sharp corners at the transition.  About Rich Hale and the old school thing, in case ya didnt notice, Rich was a farrier before he got into blades, how much more OLD SCHOOL can ya get than to shoe horses?

[Stephen Olivo]

So peter ross was talking about finger oils in that episode.  For a long time people have been told not to use oil in firework.  It mostly comes from schools.  Don't know why.  They have been taught chalk.  I use oil all the time on my files as they make the work easier and I never have to deal with a pin.  I once got chided by someone on another website for using a large rasp/file on hot steel along with the oil thing.  It took a while to explain it all to him.  I haven't been able to take a class from peter ross yet but hopefully some day.  

[Jim Coke]

Stephen, 

 

That's just a guess on what Peter said about never touch filed steel..   I by no means want you to think he said that about oil...

 

Jim

[billyO]

I just found and re-watched my video and Peter says, "the oil from your fingers keeps the file from cutting".

 

And Steve, to clarify, I said that trying to forge the sharp 90 will tend to cause a crack when you pull the tenon, not prevent one.  That's why I was filing the tool in the first place (which was the basis for the original question), to remove the sharp corners, and I was using my sense of touch because with the light in my shop this afternoon, I could feel any sharp corners better than see them in the butcher part of the tool.

[Stephen Olivo]

No that was literally what he told him in the episode.  Seen it many times as I love the woodwrights shop.   http://video.pbs.org/video/2365004964/

took me a while to find it and make sure I had the right episode.  I want his bench anvil though :D

[Stephen Olivo]

 "no sharp edges that would prevent cold shuts"  It was the wording you meant no sharp edges that would cause cold shuts"

[DSW]

No that was literally what he told him in the episode.  Seen it many times as I love the woodwrights shop.   http://video.pbs.org/video/2365004964/

took me a while to find it and make sure I had the right episode.  I want his bench anvil though :D

 

 

 

Thanks I hadn't seen that one. I used to love that show, but unfortunately it's not shown on our stations here.

[billyO]

 "no sharp edges that would prevent cold shuts"  It was the wording you meant no sharp edges that would cause cold shuts"

  :o GASP...I WAS wrong in the first post....."Inconceivable!!!!!!"

 

Sorry Steve, apparently I need to work on my editing as well as memory exercises..... :rolleyes:

 

Anyway, do what I mean, not what I say.... :P

[rockstar.esq]

I remember Peter's comment on that episode and I thought it was odd.

 

I once had a professor tell me that oils had no place in milling machines because they reduced friction which in his mind equated to reducing cutting ability.  I pointed out that cutting oil is often used to reduce cutter wear, and part distortion due to heat.  My comments were not welcome.

 

I've also read in Alexander Weygers book that files coated in grease or oil were once thought to be "spoiled".  He advised cleaning them with battery acid to etch oil and metal pulp from the files teeth.  As my foggy memory serves, he said an oily file might take a bit more pressure to start a cut but certainly hasn't lost any utility for it.

 

Finally, I've read of gunsmiths who advise wearing gloves while draw filing to avoid leaving finger prints on the metal's surface prior to blueing operations.  It makes sense that grubby fingerprints on finish work isn't desirable.

[DSW]

Finally, I've read of gunsmiths who advise wearing gloves while draw filing to avoid leaving finger prints on the metal's surface prior to blueing operations.  It makes sense that grubby fingerprints on finish work isn't desirable.

 

 

I personally seen the results of finger prints on blued gun parts. The oils from your hands don't allow the blueing salts to rust the surface evenly and they leave a very clear and distinct "look" to the finished piece.

[Francis Trez Cole]

when I took a class from Peter I found him to be very helpful with every thing. He dose not hot file he says there is no historical record that you would want to hot file. the way he explained it makes a lot of scene files were very expensive and hot filing wares out files. If you use a file for hot filing then it should be marked and used for only that. From what I saw in his shop the benches were very clean and the files dry and very sharp. He kept them in boxes that they were shipped in.

As far as the flat cross peen I asked the same question He explained it that a round peen works more like a chisel He talks about it in the wood wright episode where he is making bench dogs.

[Stephen Olivo]

DSW-  Makes sense in that context but why not then just clean it right before going into the salts so that you know its clean going in.  Just seems a better way then just telling people not to touch.  I haven't met many who would listen to that anyways.  

I always try to watch some of the episodes as they come online.   PBS.org is my friend :D

 

Billyo-I must reread each of my posts a ton of times and still fear I said something wrong :D

 

rockstar- I have found if you need to press a file more than just a little the teeth are clogged and its time for a brushing with a stiff brush or your asking the file to take bigger bights than it is meant to take.  I have always found friction to be the enemy of cutting as your trying to part or split the material.  Kinda funny how logic just doesn't seem to work for some people huh :D  Plus some people are just set in their ways and don't like to be proved wrong so they just get more intrenched.  Thats also why I always tell people to try what I say and then find other ways and try them as well. That way they aren't just trusting what I am saying to them but what they find works best for them.  I always found the best teachers were the ones that made you question things and in asking the question find out and decide for yourself not just be told.  I am a fan of the path walked backwards.

[tzonoqua]

Ya know what, sometimes people just say stuff as well. Fills the air. 

if you're sharpening sometimes you get burrs, they hurt when they go in, and hurt more to dig out.  I've used files on hot metal, hot rasping, works a treat, especially when making tongs and smoothing off the riveted section. Also, if you are treating metal with a chemical, certainly you degrease first. And yeah, sometimes metal is hot, black hot, thought it was cold but it's hot and it hurts hot. But as a blanket statement, don't touch bare metal with your bare hands when filing?? I do when it's cold, use your own judgement.

[Anachronist58]

Hello, All.  WOW.  The longer these threads run, the more challenging it is to put in my two cents (and actually be worth two cents).

I feel unqualified to challenge the diverse and venerable viewpoints of my fellow contributors, but here's my copper:

 

Peoples' body chemistries are widely variable. Fingerprint "oils" can be quite corrosive. Some of us may handle unprotected (steel) and suffer little consequence. Others can burn the metal almost instantly by touching it.  I have seen this in both aerospace components I have finished, and in cutting tools I have processed.  In fact, for certain end users I would have to thoroughly protect the product to prevent oxidation disasters (scrap).

 

Oxidation can be a runaway train. Often, a fingerprint burn will tunnel toward the core of the workpiece (pitting) faster than it spreads across the surface. I am not a Metallurgist, but pitting is a fire that keeps burning until it is put out. So, it is not dirt, but damage, a matter of metal removal and not cleaning. Since gun bluing is a highly delicate oxidizing reaction, rust (or grime) can't be good.

 

Rockstar.esq said, "I once had a professor tell me that oils had no place in milling machines because they reduced friction which in his mind equated to reducing cutting ability.  I pointed out that cutting oil is often used to reduce cutter wear, and part distortion due to heat.  My comments were not welcome." Colleen says, "sometimes people just say stuff".  I am one of those people from time to time, and the more I yak on this forum, the greater I risk standing to be corrected.

 

But Rockstar, your "professor"  was just full of "himself'.  The Utopian Ideal of Metal Removal is the Absence of Friction, and the efficient transfer of heat into the waste (chip) through upset deformation of same (chip). When you see that chip "curl" out of the way, your are making good time. Microscopic Inspection of this waste reveals a surprise - Milling, Drilling, Reaming, Grinding, and Filing at their optimum rates all produce chips very similar in appearance.

 

I used to dread sending certain Reworked tools like twist drills to the "Manual" Cell. Some were of the philosophy that "Oil (cutting fluids) and machining do not mix".  That's why one of my reconditioning tools was an abrasive cut-off saw! :wacko:

 

Don't get me started on titanium. 

 

Filing: I would endorse protecting and enhancing the performance of files with oil except for one reason: Unanticipated chemical reactions to the heat or fire of the Forge have been DEADLY.   Some of you have lost Friends or Family, and we, as a community, have suffered along with you in this.  Be it from letting our guard down about Zinc, (that's me) or letting Chlorinated Solvents (Brake Cleaner) sneak their way into the forge. Many on this Excellent Forum can add much I am sure,

It might be useful to Pin a link to Safety to the top of our Index, as well.

 

So lube your files when you know it's safe to do so, and I won't forge while drunk.

 

I am constantly having to clean my mind of Superstitions I have learned, but some of them are useful (don't eat that) until proven otherwise. Every one knows not to start the forge with a cup of Gasoline. Don't ask me how I know that.

 

Humbled to dwell amongst you, Robert