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lathehand
10-17-2006, 04:08 PM
The Box O’ Mistakes is a little cardboard box in one of my toolboxes drawers. It is where I keep the results of less than spectacular work. It is helpful to pull an item out when giving “ I wouldn’t do that” advise, the memento of metallic mayhem gives weight to the words. I have my “save time and only drill the holes as deep as the threads (with chip packed broken tap) work piece”, and the “ I can mill right across that flathead bolt, it won’t unscrew” part. I like to draw lessons from each piece. They also come in handy for consoling a coworker. “That’s not so bad - look what I did when I tried milling that 6061 dry and wasn’t blowing out the chips”.
Last week I added the remains of a shattered ½” reamer. I was reaming in mild steel. I wasn’t using any coolant or cutting fluid because the work piece would have taken hours to disassemble and clean out the oil. I didn’t want to build a clay dam or duct tape all the cracks; I just wanted the job done. The cut was through two inch thick plates with about 1/8” between them. The chips from the bottom plate would pack in the space and not clear. The cutter grabbed in the second hole, so did I stop and reassess the situation? No, I wanted the job done, no time to think things through. Did I look at the cutter to see if it was picking up metal? Again no, just tighten the chuck and on to the next hole. When the cutter again spun in the chuck the STOP NOW light should have blinded me, but hey, only one more hole to go, so git er done. Now I really tightened the chuck, and the chuck did a great job of keeping that reamer shaft spinning, even as the end of it stopped spinning. Luckily I was able to drive the remains of the reamer through the hole, adding some nice spiral “dumbass” marks to the bore.
When things are not going well, forging onward without stopping= bad idea.

charlie coghill
10-17-2006, 05:56 PM
I don't have a box big enough to hold my mistakes, but you do have a good idea.

John R
10-17-2006, 06:10 PM
I used to hang them on the wall....called it my wall of horors. Did not mean anything to most people but when a mechically inclined person would visit it was good for a few laughs
John R

IOWOLF
10-17-2006, 06:38 PM
Mine get recycled to something smaller,I have a lot of needles,and chips.;)

jkilroy
10-17-2006, 08:22 PM
Box? Shoot, more like SHOP FULL of mistakes. :O All of the stuff that gets done right damn well better get sold! :D

kap pullen
10-17-2006, 09:34 PM
Heck,

After all these years, I must have a dumpster, or two full.

I remember the first bevel gear I cut with the two little teeth at the end!

My ex wife would ask me why would I show something like that off.
Well, why not? Everyone can learn from it, especially me.

Most in this world don't have the ability to even make that scrap part.

Of course, I have a warehouse or two full of heavy, and light machinery parts somewhere that have done their jobs, to print, and just on time.

If all you have is a little scrap box, or drawer, be HAPPY.

My biggest screw up was a box machine side frame, 2" thick, by 36" by 48", blanchard ground steel, and made to the wrong print.

Kap

TECHSHOP
10-17-2006, 10:09 PM
The other day I needed to make pair of parts that "mirror matched", compound angles, several holes that needed to align between the two. Very carefully calculated, checked the "prints", set up, and made the parts. They where "perfectly" matched to each other, as measured to the limits of my ability to use my tools. Bolted them into place, and tried to fit the rest of the assembly together...I'm getting better -- my mistakes are much more amazing.

I really don't think these plans are designed to work. All the important things are just wrong...

Prototype A, Mod II, in the drafting stage.

wierdscience
10-17-2006, 10:14 PM
The only real differences between a master and his apprentice is the master can fix his mistakes and by learning from them makes fewer.

BobWarfield
10-17-2006, 11:00 PM
Mistakes on the workpiece get put into my rough stock bin for reuse later. More serious mistakes are placed in a box labeled "dull cutters". That's where things like endmills, taps, and the like snapped in half live. You'd definitely have to call that a dull cutter. Generally, the event that dulled the cutter was exciting enough and avoidable enough to be called a mistake.

I kid myself that when I switch to CNC, I will have fewer mistakes. I suspect I will have a lot more dulled cutters, however. Maybe a dulled vise, some dulled table clamps, and if I am really ingenious, perhaps a dulled mill table or even a dulled spindle. Gonna have to get a bigger box!

Best,

BW

John Stevenson
10-18-2006, 03:51 AM
Reading Kap's post of the bevel gear with the two small teeth remind's me of the Alfa Romeo half shaft with 42-1/2 splines.

Not only did I learn a valuable lesson on dividing I also learn some new swear words from the customer.

I've remembered both. :D

We are all human and prone to make mistakes but at least in metal they can be construed as modifications.:p
My most recent one was the attachment to hold the digital scale on the tailstock.

First time I needed a short drill the bracket hit the toolpost.
Result: it wasn't a mistake but now it's showing a large piece carved out it's a working mod.:rolleyes:

.

madman
10-18-2006, 07:51 AM
I was working on some giant aircraft landing gears years ago. On a big converted wilson hydraulic profiler converted to CNC fanuc 11 m controls with a PC and gecko box. Any how some kinda brain Fart. The machine made loads of noise ect. So as i was sitting there reading a Good Magazine and it started to load up i didnt even move but just turned down the feed control and it stopped growling and kept going. About twenty minutes later i stop the machine retract z head to check the inserts. Horror of Horrors a massive two inch deep trench 8 12 inches long burrowed into the main body of the gear. All 4 o
of them. OOPS. HM. I wonder how that happenned. Anyhow i guess this might be the scrap record. ?? Anyone done worse?? PS i didnt get fired or even spoken harshly too. I think managament knew it was a cobbled up piece of unique junk.

BobWarfield
10-18-2006, 09:55 AM
So as i was sitting there reading a Good Magazine and it started to load up i didnt even move but just turned down the feed control and it stopped growling and kept going.

That's hilarious. I'm envisioning you not even really looking up from the magazine, but just casually reaching out to turn down the feed, and then pulling pack to turn the page. Meanwhile the machine is practically walking around.

Thanks,

BW

Wirecutter
10-18-2006, 09:56 AM
I usually keep the really good mistakes out in plain view so I don't forget them.

Someone here had a quote from their father that I really liked:

"Learn from the mistakes of others - you'll never live long enough to make them all yourself."

-Mark

DICKEYBIRD
10-18-2006, 10:21 AM
See my signature....there are many, many reasons I chose it.:)