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Ruined my tap

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ericc

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I just ruined a 5/16 NC 18 tap trying to thread a hole in a shop made t-nut. It never started cutting, and the lead in threads got flattened. The tap was a no name one with the black finish and only the size stamped on the shank. The t-nut was forged from a piece of a railroad spike and it was as forged, not annealed. I tried annealing it, but was probably too late and the damage was done. The forging sparked as low to medium carbon, definitely not mild steel. The tap sparked as high carbon, about 95 points of carbon. It was not HSS, but those generic taps almost never are, even if they are marked tungsten. A photo is attached. Maybe the end can be cut off and it could be used as a bottoming tap.

IMG_20190113_214658.jpg
 

Z2V

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Ah, just chunk it and get a known brand quality tap to replace it. If it wouldn’t even start a thread as a taper tap, why would it work if you cut off the starting threads and go straight to full thread depth?
My $.02
 

T Bredehoft

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Unfortunately inexpensive taps are also cheap.
 

ericc

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Some of these taps are not even that cheap. I just bought a set at Lowe's in an emergency at work. It is their Irwin Hanson set. It didn't look good when the tap wrench stripped its threads when tightening down on the smaller two taps. The 8-32 was not even good for one hole. It wallowed out the hole so badly, the screw wouldn't even engage. It just slipped right out. It's funny, too, since the package said that the taps were made in USA. The next day, Fastenal was open, and we got an FMT (Made in China) spiral point tap. It was expensive, but much better the the "USA made" ones from Lowe's. You just don't know what you're getting these days.

What kind of life should one expect from taps? I know, I know, the Internet says if you don't want to break a tap, throw it away like a master gunsmith after successfully tapping one hole. But some manufacturers say thousands of holes. There is no way that any of my taps, no matter what the brand, last for thousands of holes. Is that because they only get this life when machine tapping? Oh yeah, that stupid Irwin Hanson tap that couldn't tap even one hole got salad oil, since there was no cutting oil at the office.
 

markba633csi

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Quality at Hanson must have slipped cause I have older Hanson taps (and drills) I've used dozens of times and they are still OK
Mark
 

JimDawson

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What kind of life should one expect from taps?
The answer is.... It depends on the phase of the moon :rolleyes:

I have had taps last for hundreds of holes or not even make it through the first one. We have one 10-24 thread forming tap that has done over 2000 holes in 6061 and is still going. I bought five German 5/16-18 spiral flute taps (~$20 each) and got about 3 parts out of each in 304 SS, then switched over to a Fastenal spiral point and finished the 200 piece run with it. I wanted the spiral flute because I was going an inch deep in a blind hole and wanted a tap that would pull the chips out.

The Hanson and Vermont American taps from the local hardware stores are junk in IMHO. When I have to go to Fastenal I usually pick up a few of the taps that I use all the time just to have them in stock.
 

mmcmdl

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I just bought a set at Lowe's in an emergency at work.
This is where you went wrong :grin: What kind of quality did you you expect from these types of stores ?
 

WalterC

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This is where you went wrong :grin: What kind of quality did you you expect from these types of stores ?
At least he didn't go to wally-mart- the professional industrial tool store. (snicker).

I have a cheap set and a good set. I use the cheap set on thin material first to save the good set. Besides, the cheap stuff is really for repairing threads, not cutting new ones- so they say.

I have a set of old 60's- 70's? Krome edge craftsmans that do a decent job. I found them in the box at my FIL's garage after he passed away- never used.
 

ericc

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Those Krome edge Craftsman's are great, even though the finish looks a little funny. I buy a lot of taps at garage sales, so it is a mixed bag. There are always emergencies at work and someone is always dashing off to get something. Recently, the coffee maker broke, and the replacement broke in 3 days. Ended up ordering one instead of going back to the big box store, and it's been 3 weeks, no package. Man, you never can trust anything these days.
 
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