Tap that was etched wrong

[Incogneeto]

Yep Sh&t happens we got rush parts had to build fixtures, Program parts working through weekends. Boss ordered tools we were waiting on the Damn Threadmills all else was ready. Finally threadmills

show up I grab one throw it in machine and we are running 4000 parts needed and we are just spitting them out. alternate supplier for our customer is asking how we do it cause they can't

figure it out . Boss tells me get the tool #s so we can help these guys out. Looking at the threadmill and Damn it has a flat on it. Oh Crap!!! It was an acme. 1000 already out the door!!

Luckily they never figured it out. We switched as soon as we got correct Threadmills . All my fault first time thread milling didn't even look at the package just took what the Boss handed me

and ran. And yes we gaged just fine either way. Lesson Learned.

[Matt@ModernMold]

I ran into a problem where I scrapped two parts with a days worth of work into it because I blew up a tap in both of them. 1/2-13  so pretty basic stuff right here.  I couldn't not for the life of me figure out why i kept breaking taps.  Then a few days later after tapping the rest by hand I found out that the tool crib stocked helicoil taps in the normal tap spot.

[Matthew Hajicek - Singularity]

Ouch.

[taperlength]

Was doing a job recently where we were threadmilling a large oddball thread in some parts.   The manager did not have time to order a gage so  he had the lathe leadman make GO and NOGO gages on the CNC lathe.

On the first part, I gave it some plus comp and ran one hole and reset it to check the thread.  The gage went in.   No way....it should not until I've added some minus comp.  So I got a thread mic and checked the gage.  They had made it to the _external_  thread pitch dia.....not the _internal thread pitch dia.   Common mistake.

[jeff]

I ran into a problem where I scrapped two parts with a days worth of work into it because I blew up a tap in both of them. 1/2-13  so pretty basic stuff right here.  I couldn't not for the life of me figure out why i kept breaking taps.  Then a few days later after tapping the rest by hand I found out that the tool crib stocked helicoil taps in the normal tap spot.

That does suck!

I learned that lesson a long time ago, now I ALWAYS check the tap to make sure it's the correct one. 

[Allan]

First off inspection by someone other than the machinist who made it.

QC department if it exists; another machinist, foreman whatever.

That second inspector signs off on the quality.

That is standard practice in production shop environment; ISO certified or not.

 

 

 

[mkd]

I ran into a problem where I scrapped two parts with a days worth of work into it because I blew up a tap in both of them. 1/2-13  so pretty basic stuff right here.  I couldn't not for the life of me figure out why i kept breaking taps.  Then a few days later after tapping the rest by hand I found out that the tool crib stocked helicoil taps in the normal tap spot.

I ran a large ~1.0" STI tap by mistake once years ago. Even with the hole prepped for a regular hole in aluminum, the 50Taper spindle never knew the difference. Still kick myself for not stopping and looking at the mismatch in sizes.

[htm01]

I'll refrain from blaming anyone or anything, but I have to ask how many people realistically check their tap before using it? I know if I ordered a 1/2-13 tap and it came in a little package marked 1/2-13 and it was engraved/etched 1/2-13 and it was from a known brand I sure would not have checked it. True enough maybe the plate should have been thread gaged in inspection somewhere... This surely falls in the 'holy crap how did this f*&%ing happen?!' category. On a side note, how long did it take you figure out it was a metric thread? I think I would have been scratching my head for a long time on this one. 

with the old eyes i have to check, can't read the damn  small faint writing anyways

[JAMMAN]

That's bad, sorry. Never got a tap that was etched wrong but I do have a pin gauge in my hand etched .344 - and it mics at .333 sent us in a spin for a couple hours setting up a small boring bar.

 

I did get 2 HSS parting tools in one time that looked identical, one of them was hardened and one was not. 

 

Sorry you had problems.

[M Horton]

Sorry to hear about the situation. mistakes are common with mass repetition cycles. it's more obvious why robotics are more desired with repetition huh? I'm having accepting the fact the part produced for an outside source was produced without any inspection from the previous craftsman though, at least half a** check the first part dimensions. Threaded hole fitment being a constant priority on contracted parts. I've had quality control sign off on a machined part that wasn't to the print, but was machined exactly as the model provided by client. In the end, you can guess who was the one held responsible(lol lucky me). In the end, you live and learn and further tooling purchases can rely on a more reliable supplier. You'll never fall short with OSG hypro series taps in this case. Pay a little more for a qualified machine tool as you'd pay a little more for a qualified machinist. I do appreciate the reminder on never assuming proper completion from another's work ethic in this trade.