• This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn more.
  • PLEASE: Read the FORUM RULES BEFORE registering!

Goofs & Blunders You Should Avoid.

mephits

Iron
Registered Member
Joined
Nov 18, 2016
Messages
19
Likes
8
<Dusts off his ragged, abused bio-chem major hat> Pretty much anything which oxidizes readily can catch fire or explode in dust form. Note that this includes many forms of iron and aluminum. It has to do with mass-to-surface-area ratio. Oxidization is a heat-generating reaction (exothermic, to use the $5 term). If you have a big mass to absorb that heat and little surface area at which the reaction can happen, you don't get much except for the formation of an oxide film (i.e., rust or patina). When there's no place for that heat to go internally, all it can do is go out into the environment. In a pile this can quickly become a fire. Floating around airborne, this can go "boom!" Just yet another reason to keep your workspace clean!

[edited for clarity, 12/6/2016, 6:13 pm CST]
 
Last edited:

savarin

Active User
H-M Supporter-Premium Member
Joined
Aug 22, 2012
Messages
1,562
Likes
1,974
I have to show my stupidity in action in case anyone else attempts this.
I did not have sufficient kerosene to totally immerse the burning tip on my spark eroder so resorted to trickling it on with a spoon.
Whoops, bad move, it got hot enough to hit its vapor point and ignited.
The fireblanket made short work of the flames but not before they had melted all the solder joints and burnt off the insulation.
Luckily the coil is untouched so a rebuild will be quick.
burnt-eroder.jpg
 

mephits

Iron
Registered Member
Joined
Nov 18, 2016
Messages
19
Likes
8
As a total newbie, I have a completely honest question. Why would one use a volatile, flammable liquid as a coolant for a tool that has an open ignition point (that is, the spark)? This seems like an open invitation to danger. Thanks!
 

savarin

Active User
H-M Supporter-Premium Member
Joined
Aug 22, 2012
Messages
1,562
Likes
1,974
The kerosene works extremely well as long as the ignition point is kept submerged.
I have burnt out at least 6 broken taps, made a couple of tabbed washers in 1.2mm stainless with no problems.
The fault here was mine in only dribbling the liquid over the contact area which was 12mm in dia.
The liquid is not only to cool the point but to flush debris away.
 

Superburban

Active Member
Active Member
Joined
Jan 2, 2016
Messages
300
Likes
244
Liquid kerosene will not burn. Like gasoline, and diesel, it needs to be mixed with oxygen to support combustion. Gasoline appears to burn, because it vaporizes easily, and that is what you see burn when you toss a match in a bucket of gas. Unless it is a super hot day, you can toss a lit match in diesel or kerosene, and chances are the match will burn a few seconds, then go out. You need the vaporization of the fuel to get the flames. That's what Savarin caused by slowly adding kerosene to hot metal with sparks.
 

David S

Active User
H-M Supporter-Premium Member
Joined
Nov 18, 2012
Messages
1,038
Likes
676
And a lot of automotive fuel pumps are submersed in the fuel tank and the fuel flows right over the commutator and brushes.

David
 

Tony Wells

Former Vice President
Staff member
Administrator
Joined
Jan 22, 2011
Messages
6,870
Likes
19,421
For much the same reason, cooling. Which is why you really shouldn't make a habit out of running your fuel tank low. What isn't used in the injection system is sent back to the tank, so there is a constant flow. The pump is never "dead headed".
 

Bill Gruby

Global Moderator
Staff member
H-M Supporter-Premium Member
Joined
Jul 13, 2012
Messages
5,430
Likes
1,900
A friend and work associate passed away last week . While at the wake yesterday some stories were told that were long forgotten.

A young GMI student was working at our plant and was in the Forge Shop one day. He decided that if he was to learn, he needed to help. Sounds like a plan so far. Bob, my deceased friend. asked the kid to help him. Now, one peculiar thing about Bob, he was a stickler for doing things to the letter. You really needed to watch how you said things around him. Ok, Bob asked the kid to hold a large pin while he pounded it into the hole. Before anyone could caution the kid on choosing his words. he yelled to Bob, got it, when I nod my head go ahead and hit it. Without hesitation Bob did just that, he hit the kid right on the head. Not hard, but enough to let the kid know he said the wrong thing. I don't think that kid will ever forget that day.

That is a true story people, you just can't make those things up.

"Billy"
 

Tony Wells

Former Vice President
Staff member
Administrator
Joined
Jan 22, 2011
Messages
6,870
Likes
19,421
Sounds very much like something I would do. Teach people to think about what they are saying. What's that old saw....."Make sure your brain is in gear before letting out the clutch on your mouth" or something like that.
 

Bill Gruby

Global Moderator
Staff member
H-M Supporter-Premium Member
Joined
Jul 13, 2012
Messages
5,430
Likes
1,900
Then there was Rawhide. He worked at GM on the third shift bar line. (Automatic Screw Machines) He slept a lot. He ran a bank of 4 1"-60 New Britains. Smash ups were inevitable. One set-up man decided to get even. The machine totally went down, drills, form tools. cut off blades, everything broke. When the machinists were done the set-up man went to work.

Changed all the tools and broken fixtures. Now to stock it up, this is where the fun began. Instead of loading it with the .967 solid stock, he went to the tool crib and cut off all the handles on the bad brooms. He painted them all black and loaded all the spindles with them. He finished the set-up and gave the machine back to Rawhide to run. True to form Rawhide engaged the spindles and went back to his stool and fell asleep. Than machine ran wooden outer races for the next 3 hours.

The parts were awesome, fit the gages perfectly. Ole Rawhide had some tall explaining to do. It seemed like he was upstairs for hours. Final total 1073 wooden cups.

The guys were telling these stories over and over again at the wake. We decided then and there to get together once a month. More to follow.

"Billy G"
 
Last edited:

SapperDave

Iron
Registered Member
Joined
Nov 17, 2016
Messages
5
Likes
5
<Dusts off his ragged, abused bio-chem major hat> Pretty much anything which oxidizes readily can catch fire or explode in dust form. Note that this includes many forms of iron and aluminum. It has to do with mass-to-surface-area ratio. Oxidization is a heat-generating reaction (exothermic, to use the $5 term). If you have a big mass to absorb that heat and little surface area at which the reaction can happen, you don't get much except for the formation of an oxide film (i.e., rust or patina). When there's no place for that heat to go internally, all it can do is go out into the environment. In a pile this can quickly become a fire. Floating around airborne, this can go "boom!" Just yet another reason to keep your workspace clean!

[edited for clarity, 12/6/2016, 6:13 pm CST]
Aluminium and Iron dust mixed together happens to make a thing called Thermite. Little spark and that mix will burn through anything. Very dangerous stuff.
 

RJSakowski

H-M Supporter - Premium Member
H-M Supporter-Premium Member
Joined
Feb 1, 2015
Messages
2,764
Likes
2,831
Aluminium and Iron dust mixed together happens to make a thing called Thermite. Little spark and that mix will burn through anything. Very dangerous stuff.
It's actually aluminum and iron oxide dust. The red iron oxide (Fe2O3) or rust, that is. I'm not sure that the black oxide (FeO2) or scale from hot worked steel reacts the same.
Edit: This was not intended as a correction on the spelling of aluminum/aluminium. Married to a Brit, I have come to accept either spelling.
 

Bill Gruby

Global Moderator
Staff member
H-M Supporter-Premium Member
Joined
Jul 13, 2012
Messages
5,430
Likes
1,900
Helicopters with HMM 161 carried 2 Thermite Grenades on every hop while in Viet Nam. The Crew Chief was the only one that had access to them. They were issued when the day began and turned in at days end. If a chopper went down and was not retrievable they were used to destroy it. I destroyed a CH 46 on one occasion. ($6,000,000 +) It didn't take long to reduce that chopper to a pile of nothing. Thermite is fast.

"Billy G"
 
Last edited:

uncle harry

Active User
Active Member
Joined
Aug 19, 2013
Messages
650
Likes
351
Aluminium and Iron dust mixed together happens to make a thing called Thermite. Little spark and that mix will burn through anything. Very dangerous stuff.
Thermite needs a touch more than a little spark from my memory. I have heard that thermite users would also use a small amount of powdered magnesium to get the reaction started.
 

Bill Gruby

Global Moderator
Staff member
H-M Supporter-Premium Member
Joined
Jul 13, 2012
Messages
5,430
Likes
1,900
Chinook is a Army CH-47, Tony. A CH-46 is it's smaller cousin used by the Marines. It's a common mistake. The Army turned down the 46 because it was small. We had CH-46D models. We didn't have any trouble with size or payload. The GE-10 1400 horse engines were more than adequate.

"Billy G"


http://www.military-today.com/helicopters/ch46_sea_knight.htm
 
Last edited:

Tony Wells

Former Vice President
Staff member
Administrator
Joined
Jan 22, 2011
Messages
6,870
Likes
19,421
Oh, I know, Bill.....just what you were talking about reminded me of that project. We had units in Kuwait, one featured in that article there at Wheeler, one under construction at Hunter in Savannah, GA. And plans for many more JAN projects. The Texas National Guard brought one down to us to play with. :) If I can find some footage, I may post it. It may be long enough now. This was all pretty tightly held information at the time, on the technical side, and now as far as I know there may still be ongoing litigation that might make it unwise to get too much into.

Its far OT anyway. Interesting, but OT.
 

Bill Gruby

Global Moderator
Staff member
H-M Supporter-Premium Member
Joined
Jul 13, 2012
Messages
5,430
Likes
1,900
Somewhere in my collection of combat pictures I have before and after pictures of the chopper I destroyed. I flew on that chopper for 17 months an average of 9 hours per day, 24/7. It was heartbreaking to watch it go. In all I crewed choppers in combat for 37 months for a total of over 7,000 hours. Most of those hours were flying MedEvacs. It wasn't the best life but I volunteered for it so it was what it was. If a pilot was hit he was removed from the cockpit if he could be and the crew chief took his place. The old man taught all crew chief the basics of flying a chopper. I had to on a number of occasions. Once when both pilot and copilot were wounded.

OK, I have held this thread hostage long enough with war stories. Let's get back to the original topic. Too many memories are popping into my mind and the mind is a terrible thing to waste.

"Billy G"
 

dieselshadow

Do you smell something?
H-M Supporter-Premium Member
Joined
Aug 21, 2016
Messages
171
Likes
158
Bill, you are indeed a hero. Please accept a huge "thank you" and know I have a lot a gratitude and respect for you and others who volunteered. My hat is off to you sir.
 

Bill Gruby

Global Moderator
Staff member
H-M Supporter-Premium Member
Joined
Jul 13, 2012
Messages
5,430
Likes
1,900
Nope, just another Marine crew chief doing his job, getting as many as he can out of harms way and hopefully home safe. Sometimes it worked, sometimes not. but I did my best and that's all the Marine Corps expected. Once in a while I do miss those days, but it is an extremely fleeting thought. LOL

"Billy G"
 

dieselshadow

Do you smell something?
H-M Supporter-Premium Member
Joined
Aug 21, 2016
Messages
171
Likes
158
I too was a Medevac crewchief. Only I was in Blackhawks in the Army. Wasn't during wartime either. Although we did get shot at once, I never did what you did or for the duration. I can't even begin to imagine the stories you could tell. That's a huge accomplishment on your part Bill. There's always a cold beer here for you sir.
 

Tony Wells

Former Vice President
Staff member
Administrator
Joined
Jan 22, 2011
Messages
6,870
Likes
19,421
I checked.....I still can't (or am not supposed to) release any tech data including photos or video of that product. It was designed to service anything from a Kiowa OH-58D up to the CH-47 Chinook. I have the flight and service manuals around here somewhere. Maybe when the lawyers get done I can share some of that project. It was pretty fun.
 

Wreck™Wreck

Active User
H-M Supporter-Premium Member
Joined
Sep 29, 2014
Messages
1,918
Likes
1,462
Friday I made a bunch of parts in POM, 1/4" bore thru, .375 +.002 -.000" counterbore .312" deep using a 3/16" carbide boring bar.

The last 2 lines of the program were rapid moves .200 X, 1.000 Z then 2.000 X, Z 1.000 for working room for the next part change.

I failed to insert the decimal point on the first rapid move, this resulted in the obvious. The tool went right through the part, did not break the bar however which was nice.

brokenpom_zpsnnyd02eu.jpg
 

master53yoda

Active User
H-M Supporter-Premium Member
Joined
Jan 15, 2013
Messages
168
Likes
27
how about clearing swarf on the lathe. Never ever use ones hands to push, clear, untangle the swarf building up. Use a brush to push it away or perhaps smooth handled pliers to try and grab some. The idea is that you don't want the pliers to get caught and pull your hand into the works.

Best of all turn off machine and remove the swarf and build up.

David
I cut my finger to the bone trying to flick off a piece of swarf After i shut off the lathe but before it stopped turning. That was 40 years ago and that end of my finger is still dead feeling.

Art B
 

Bill Gruby

Global Moderator
Staff member
H-M Supporter-Premium Member
Joined
Jul 13, 2012
Messages
5,430
Likes
1,900
You probably cut the nerves if you cut that deep. Nerves rarely heel, they stay severed. Don't ask how I know.

"Billy G"
 
Container Above bottom breadcrumb