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Metric tap & dies

4K views 32 replies 8 participants last post by  hogcowboy 
#1 ·
I found myself needing an 8mm x 1.25 tap the other day.

Realized I have virtually NO metric taps. At least 2 full sets of SAE plus "extras."

Went looking on Ebuy and Amazon.

Could pick up a new Snap-On TDM117 kit, 25 pieces, for around 180 clams.

But the guys on the automotive forum warned me off these, said they're carbon steel and very brittle.

Suggested the MACHINISTS would only buy "high speed steel" taps, followed by a long discussion of how and why noobs break taps.

McMaster Carr has a 25 piece metric HSS tap/die kit for $189.
 
#2 ·
Have to say I'm surprised that Snap-On would have carbon steel sets. That said, the intended use would be the determining factor. If you are only going to be working with cast iron, mild steel or aluminum, the carbon steel will be fine. Rule of thumb is the cutting tool must be harder than the material being cut. Duh... pretty logical, huh?

Keep in mind, HSS can be brittle, too. That's the difference in the cheap sets vs. quality sets... it's in the tempering process. Cheapy's chip more easily... and break more easily, and we know removing broken taps is not a fun job.
 
#4 ·
I'd have a seriously big pile of used taps if that were the case! Over the years I've literally tapped thousands of holes for local mfg's and it's not unusual to have a tap last for a hundred holes or more. (And I've also broken a tap or two on the first use.)
 
#5 ·
I've not had very good luck with the cheap Chinese sets but it got me started ~50 years ago and now have a pretty good set by doing just that, replace each one, one at a time. Of course, some good ones have been replaced as well with usage and darn breakage. My metric set still isn't completely replaced but my standard is now much much larger than the original. I'd really hate to have to replace that set now.
 
#6 ·
A few months ago I lucked into finding a plastic container of mostly metric taps at a pawn shop. Since I didn't have hardly any metrics I snatched this thing up. 5 bucks got me about 40 different taps. Some repeats but that's okay, and several different types: Bottoming, Taper, plug, spiral. Mostly Greenlee but a few other brands too. Made in Germany and Guhrig maybe? Most seem to be a decent quality and in good, sharp condition.
 
#7 ·
...I lucked into finding a plastic container of mostly metric taps at a pawn shop. [$5] Mostly Greenlee but a few other brands too. Made in Germany and Guhrig maybe? Most seem to be a decent quality and in good, sharp condition.
I've been out-pawned! Congratulations!

I went to three shops looking for taps. Nothing but dirty, rusty junk that had been rattling around the bottom of people's toolboxes for years.


 
#9 ·
I seldom use Tap and Dies, Sooo.. I went to Harbor Freight and bought SAE and Metric sets, admittedly, they are "****" tools, Machinist wouldnt be caught Dead with them, BUT, I have used the SAE once and the Metric twice and they worked OK, Harbor Freight actually sells 2 levels of quality of Tap sets,, I confess I bought the cheaper sets. LOL
Ed
 
#14 ·
I have a well equipped shop but it is all Imperial. Since getting into older Hondas (1960s) a few years ago, I find I am having to accumulate more and more Metric fasteners. Just to complicate matters, Honda was using J.I.S. (Japanese Industrial Standard) fasteners back then and they are different thread pitches so that will be TWO sets of Metric taps & dies! :frown:
 
#15 · (Edited)
SAE, Metric, Imperial, Whitworth.... Having to buy multiple sets of tools is annoying and expensive, but it's a real luxury when you need one to just reach into the tool box and get it, isn't it.

Here's another tapping tip someone threw out; if you DO break a tap off, if possible torch what's sticking out red hot. It will take the temper off and once cooled at least give you a chance of drilling or grinding out the remains.

On Craigslist I saw an electronic "disintegrator" used on jet airplanes and such that ate away at broken taps & such with little lightning bolts, kind of how points and spark plugs electrodes gradually get eaten away.

http://www.motorcycleforum.com/showthread.php?t=174098&highlight=disintegrator
 
#16 ·
Way off topic but it's friday :)
You just brought back a memory from the distant past for me, about 30 years ago I was working for a government contractor building all sorts of high tech top secret toys for the military, and we had a near disaster averted with one of those machines.

Our small group ( advance production, we built the 'special' stuff) were working double shifts getting a new "sonar fish" ready to go, there was literally a ship waiting to leave port and go chase Soviet submarines and they needed this 4 ton giant fishing lure.
One of the last jobs was to drill and tap on location, by hand a big ( maybe 1.5 inch), deep ( 4 inches?), fine threaded hole in the 2000 pound stainless casting that made up the top of a 'fish'. This was done from a scaffold and something slipped and the mechanic managed to break off the tap in that hole!!! ( no , NOT me, I was wiring the transducers), panic ensued, but they took it down to one of the machine shops and they used some sort of high tech lightning machine to disintegrate that tap and save the day.

I found a few links to the sonar fish if anyone is really bored...
http://fas.org/man/dod-101/sys/ship/weaps/an-sqs-35.htm
http://www.ussbrewton.com/gallery1/ff108658.jpg



I saw an electronic "disintegrator" used on jet airplanes and such that ate away at broken taps & such with little lightning bolts, kind of how points and spark plugs electrodes gradually get eaten away.
 
#17 ·
Even further off topic, you remember the "One Ping" in "Hunt for Red October?"

I always thought the USN should come up with a sonar that put out simulated whalesound. "One squeal."

Or one dolphin "click"

With the right receiver/operator you might be able to detect a threat with it... and unlike "One ping" not immediately give away your own presence.

Either it's a genius idea, and has already been done, or I'm dumber than dirt. Probably the latter.
 
#18 ·
It's a good idea, good thing we were ahead of that 30 years ago :)

Passive sonar was where it was all headed, everything makes noise, and even if it doesn't the ocean is full of noises that reflect off everything, it just takes really good listening devices and lots of computer power to virtually see what's down there. Back in the 80s we were building hydrophone arrays (some of them 500 feet long, slowly towed behind a ship, some fixed in positions, these things were big and complex) that could hear fish farts from miles away, and I'm only sort of joking :)

Active sonar was for playing tag with the subs, letting them know your there, you know they are there, and herding them where you wanted them to go.

When that didn't work to get them to move along the next step was a little 'love tap' with one of the sonar fish, I overhauled one that was run into a sub at high speed, supposedly this was always an 'accident', since officially it would be an act of aggression to ring their bell that way by putting a big dent in their sub. Of course, what were the odds of 'accidentally' hitting the target you've been watching with the highest tech device in existence at the time for tracking just what they were doing?

Expensive games we play...
 
#19 ·
The sqeeky 32 was used on the Avenger Class Minesweepers. I was on an older class MSO when the Avenger came out. We had Sqeeky 14 sonar for search and Identify mines. pig tails, beavers and 6Bitches to get rid of the.

Even that old sonar painted a great picture of the bottom making the job of staying alive easier. It was a hull stored towed array.

Damn that brought back some old memories. Raytheon?
 
#20 ·
No, I worked for EDO Corp, government systems division, we built all sorts of fun stuff, lots of different sonar systems, Arial spray tanks used for agent orange, bomb racks and drop tank mechanisms for fighter jets, and we made those famous $400 hammers. :).
My favorite though that I worked on was the high speed, turbine powered, helicopter towed, hydrofoil riding electromagnetic mine sweeping system, the MK-105. We called it the sea sled.


https://www.google.com/search?q=mk+...gEGmJM:;TqWRkfhTgEGmJM:&imgrc=TqWRkfhTgEGmJM:

https://www.wunderground.com/wximage/pmh4353/48

Damn that brought back some old memories. Raytheon?





Sent from my iPhone using Tapatalk
 

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#21 ·
I later did logistic support for various Naval aircraft including all MH-53 series Sikorsky Helos. I belived the Sea Dragon towed that sled.
 
#22 ·
Small world for sure! That sounds right, I remember H-53.

We made and refurbed a number of those sleds, on those I was building the turbine power packs and the tow cables for the most part.

The tow cable sounds simple but it was actually quite a complex assembly, a coaxial electrical bundle/ tow cable taking the tension load, INSIDE a compressed lengthwise fuel transfer hose. My shop built those completely, starting with hose and cable and parts from the machine shops in the plant and took them right through pressure, electrical, and pull testing. Lot's of time and hours in one of those, but it was life critical, if it failed in use there was a great chance it would go up through the rotor of the helo with dire results, the small 'ball' end of one of those cables weighed about 10 pounds and the lower junction/ bridle end was about 20 pounds of solid stainless steel.

Less well known was that here was also a larger sled that was designed to be towed by a bigger helicopter, I don't think it ever got beyond one or two test units, but it was a heck of a unit, the turbine generator for that thing was huge, I remember putting one together.
 
#23 ·
Quite a difference between actually knowing about something and experiencing it, and just watching something about it in a movie. What a very different perspective knowledge and experience gives a person, no? :71baldboy:

I'm with Wade in the "clueless" category when it comes to real life ASW stuff. I figured there was something a lot more then WWII styled pings, and that it would be much more advanced then I could imagine, but the descriptions you guys posted above were very interesting. I'm guessing that today it's even way more advanced.
 
#26 ·
My experience is about 30 years old now and you are correct Eye it had come a long way even then. Some of the mines I found interesting back in the day where the modern version of the WWII cabled mine. Minesweepers tow cables with explosive cutters on then to pop these mines to the surface to destroy then with machine gun fire. The chains holding these mines in place had pass links on them that allowed the tow cable to pass through the chain. I watched a demo in a tank in Denmark and still haven't figured out how it works.

Another is a smart mine that listens for the search sonar we used. Once we identified a possible target we would mark it in the grid we were searching and then came back and switch the sonar frequency to our identify setting. These mines would follow the search frequency and then engage their motors and move to an area we had already searched. Settle back down on the bottom and wait.

Neither of the two I mentioned were ours by the way.
 
#27 ·
Amazing. Absolutely amazing.

And compare that to the First World War. I read an account of a British submarine that got tangled up in some torpedo nets in the Mediterranean off the coast of Turkey, I think. A German officer was staring out to see when he noticed the buoy's moving about suspiciously as the sub tried to wriggle free so him and a cook commandeered a rowboat and rowed out to the nets. They lowered grenades down on ropes and forced the sub to the surface to surrender.
 
#28 ·
We did an exercise off of Kings Bay Georgia. When we were done we all anchored in a mile wide circle in 100' of water. The EOD team planted a half mine (500 versus 1000 lbs of explosives) in the middle of our group. The detonation rocked us and broke light bulbs all over the ship. And it looks just like in the movies, you get a boil of water and then the reflected shock wave sends a plume of water sky high. It is the second shock that breaks the keel of a ship.
 
#31 ·
I don't know doc, probably not as much as when we pulsed. The cutters were diamond tipped knives activated by a 20mm cartridge. When we pulsed we had a mile long 3" cable that we put different 1" thick tails on. We had 3 2000 HP twin turbo diesels at 2000 rpm. When we sent the electric pulse through the cables the load on the engines would drop them to between 600-900 rpm in about 7 seconds, 53 seconds later the engines were back up to speed and we would do it again but as an opposite pulse. This was designed to influence and detonate magnetic mines.

We were told each pulse generated enough electricity to support NYC for an hour. I never saw a floating fish in any of the exercises.
 
#32 ·
It takes a lot of power, I don't recall at all the kilowatts we put out with that minesweeper sled but I do remember very well that the test load I used for testing those turbine generators was a resistive load submerged in tank of water the size of an average home swimming pool for cooling, we could easily heat that up to a nice steaming simmer, so it was putting out plenty of wattage.
I can only imagine where sonar has gone by today, there have been so many huge improvements in electronics since my days building the stuff I wouldn't even know where to start. We were using stone knives and bearskins compared to the technology that's available today.
 
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