Gunsmithing Please Educate Me on Tap Life

[Carolina Shooter]

I'm in my first year of gunsmithing school and I could use some input on the expected useful life of a tap.

I hadn't thought much about it until I was buying some cutting oil from Brownells and read this statement in the description for the oil:

"We know of cases where all four holes for a mount have been drilled and tapped using DO-DRILL™, and the tap was still sharp enough for future use. With taps as high priced as they presently are, you cannot afford NOT to use it."

I understand marketing should be taken with a grain of salt. But is there truth to the idea that taps have a life span that short? If that's the case, I didn't realize it.

Is it just marketing babble? I've read some negative comments here about Brownells taps being low quality. Is that the issue? I'm willing to buy good tools but this made me question what to expect out of the taps I purchase.

Any guidance would be appreciated.

 

[LRI]

Re: Please Educate Me on Tap Life

Taps are used throughout machine shops all over the world. It's the quickest way to put wrinkles down a hole.

Depending on materials, they can last for hundreds of holes (thousands even at times) or they may need to be replaced in less than 100.

Tool steels are hard, tough, and often gummy. Chromoly cuts nicer than most stainless steels. (like a SS action for instance, 416@40+ rockwell can be sticky.

I personally don't use DO Drill. Go to EncoUSA and buy a 160z jug of Castrol Moly D. I works well and doesn't smell like a foot.

Buy the best taps you can. If you can afford to waste an hour digging one out of a hole (and/or replacing a customer's receiver) then you can afford another $20.00 for a quality tool.

If it doesn't cut nice, toss it and get a new one. Don't push your luck. Blind holes work best with skip tooth gun taps. They pull the chip out of the hole instead of pushing it ahead of the tool.

Form taps make the strongest of threads since they forge the material into shape. They can be used with hardened materials but you better be Jonny on the Spot with your setup feed/speed. It's a bit of a learning curve to power tap with a form tap.

I've found Guhring and EMuge work really well for us when we have to use them (both cutting/forming styles).

Hope this helps.

C.

 

[Carolina Shooter]

Re: Please Educate Me on Tap Life

Thanks a lot for the info. Very helpful.

I've been using the school's taps and haven't purchased any yet. When I do, I'll definitely spend the money for quality tools.

 

[DAVETOOLEY]

Re: Please Educate Me on Tap Life

Another vote for Moly D. I run a mixture of oil and Moly D in my chamering lathe. Good stuff. Anywhere I want a good surface finish you'll find me using the stuff.

 

[LRI]

Re: Please Educate Me on Tap Life

Dave,

Try ATF once on a scrapper barrel. Pennies compared to castrol and the finish is stellar. Its all we use now in my cnc. Buckets of the stuff!

C.

 

[DAVETOOLEY]

Re: Please Educate Me on Tap Life

Thanks Chad I'll try that on the next barrel. You using straight ATF fluid or a mix? I know I saw a noticeable improvement with 3-1 mixture with oil and Moly D.

 

[mackar]

Re: Please Educate Me on Tap Life

Good stuff. Anywhere I want a good surface finish you'll find me using the stuff.
I have confidence in your judgment

 

[LRI]

Re: Please Educate Me on Tap Life

Just straight up, good ol pink atf. Dave Kiff gave me the idea. He'd been pestering me about it for years and I tried it once last summer to appease his taunting.

It works!

Old dog, old tricks. . .

 

[HPLLC]

Re: Please Educate Me on Tap Life

http://www.brownells.com/.aspx/pid=31825/Product/FRICTION-DEFENSE-reg-XTREME-GUN-OIL

I got a couple sample bottles of Brownells Friction Defense somewhere. After using the "Original formula" for a while, I wouldn't be surprised if it is automatic transmission fluid.

Tap Magic seemed to work pretty well as a tapping fluid- at least in aluminum. I don't know how well it works in other materials but they claim it works better on harder materials.

 

[hero's machine]

Re: Please Educate Me on Tap Life

I go through atf like mad too. I use it for everything with good results too. The other day I was cutting a jig out of some mystery metal and the chit just wanted to tear....I tried a few tools and speeds when I recalled an old school tip from a buddy.....plain ol' animal fat. Comes in a block and costs a buck....that stopped the tearing and left nice threads. I would have NEVER believed it if I had not done it.

 

[hero's machine]

Re: Please Educate Me on Tap Life

Speaking atf.....I add it to my machine gear cases to give the oil some color....make checking oil easier.

 

[DAVETOOLEY]

Re: Please Educate Me on Tap Life

Many cutting oils have fatty oil additives. Usually listed as lard oil. The Texaco Transultex I used had 10% lard oil. A wise man by the name of Ferris Pindell gave me the tip about lard oil.

 

[LRI]

Re: Please Educate Me on Tap Life

kerosene works really well for tapping AL. So does antifreeze believe it or not. Ivory soap too! When I was porting Pro Stock heads years ago we'd run the burr over a bar of soap every so often to prevent it from loading up. Lots less mess than WD40.


With AL it's not so much a lubricant as it is something to prevent metal transfer. Taps in AL break when they load up, not cause the material is tough/hard.

 

[hero's machine]

Re: Please Educate Me on Tap Life

update!

lard is the answer! my dog ate all the swarf off of my lathe.....two birds, one scenar.

 

[671RTO9513]

Re: Please Educate Me on Tap Life

The old Pollock that taught me more than I can remember about toolmaking always used kerosine on aluminum, and he did a bunch of work with it.

Hog lard is the best thing to stop files clogging when filing barrels lengthwise prior to polishing on octagon and shotguns. It's kinda messy but works great. An English barrel striker taught me that.

Also, I have surface ground aluminum with hog lard. Use a fairly open wheel and keep it slathered with lard. The al can be stuck to the table with double sided tape. Messy but works.

 

[LRI]

Re: Please Educate Me on Tap Life

I use sidewalk chalk for files. Far less mess.

If you get a sticky chamber (chatter) try bacon grease!

In addition to smelling awesome, keeping militant muslims at bay, and making you hungry, it works perty dern good.

 

[hero's machine]

Re: Please Educate Me on Tap Life

Another thing I pull out is wax. I buy tubes of it from butterfeld. It's amazing what a change of friction modifier can do in a pinch.

 

[LRI]

Re: Please Educate Me on Tap Life

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 671RTO9513</div><div class="ubbcode-body">The old Pollock that taught me more than I can remember about toolmaking always used kerosine on aluminum, and he did a bunch of work with it.

Hog lard is the best thing to stop files clogging when filing barrels lengthwise prior to polishing on octagon and shotguns. It's kinda messy but works great. An English barrel striker taught me that.

Also, I have surface ground aluminum with hog lard. Use a fairly open wheel and keep it slathered with lard. The al can be stuck to the table with double sided tape. Messy but works.

</div></div>

Medium CA (superglue) has worked for me in the past with grinding AL. Toughest part is getting the chuck really, really squeaky clean prior.

Few things suck more than watching a wheel explode as a part gets shot out of a surface grinder. (I made a mess once a long time ago grinding a set of 4 bolt main caps for a SB chevy.

Spent the rest of the day truing a wheel and grinding the dents out of the chuck.

Be careful. A grinder is the most dangerous machine in a machine shop.

 

[Rprecision]

Re: Please Educate Me on Tap Life

Tap magic for AL

ATF for everything else.

As has been mentioned, there is a HUGE difference between a cheap china tap and a good amaerican tap. Buy the right tap for your job use a good fluid and your off

 

[hero's machine]

Re: Please Educate Me on Tap Life

I sent a small key into orbit today....apparently half a thou was still too much....lop.

 

[Nocalphoenix]

Re: Please Educate Me on Tap Life

Can anyone recommend a particular brand in general for taps? I am sick of ordering stuff through the mail and seeing "made in China" on everything.

 

[Clark]

Re: Please Educate Me on Tap Life

I cannot tell the difference between MolyD and Tap Magic on most holes, but when I can, like big holes, MolyD is better.


I drill and tap holes all the time and never think much about it, until I break a tap off in a blind hole.

Then I break some carbide drills trying to get it out.

 

[Wannashootit]

Re: Please Educate Me on Tap Life

I just finished drilling/tapping a K-31 receiver for a mount.
Hardest shit I've ever seen...

I used shitty Hanson taps, and it was one hole, one tap...

I won't even get into how many drill bits it took. Fortunately, I found a carbide-tipped bit by the time I got to the third hole and had chewed up a half-dozen other bits.

 

[LRI]

Re: Please Educate Me on Tap Life

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Clark</div><div class="ubbcode-body">I cannot tell the difference between MolyD and Tap Magic on most holes, but when I can, like big holes, MolyD is better.


I drill and tap holes all the time and never think much about it, until I break a tap off in a blind hole.

Then I break some carbide drills trying to get it out. </div></div>

Maybe try this:

Small EM, say .0938 or .125. Buzz it as fast as your spindle will go. Lock the quill. Use the knee. Move very, very slowly into the tool. Use coolant/oil and blow chips the whole time.

Works for me when this happens. Drills wander, end mills are much more rigid. You'll likely sacrifice the end mill. 60+ rockwell taps aren't nice to carbide. Your tap will likely have a fracture running through it. When the cutter chews through the loose pieces will prolly wedge in the hole and break the tool. Not always, but sometimes. This is where the air comes in, it'll blast it out of the hole and hopefully save the tool.

Just sucks, no gettin around it.

C.

 

[Mark Housel]

Re: Please Educate Me on Tap Life

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Norcal Phoenix</div><div class="ubbcode-body">Can anyone recommend a particular brand in general for taps? I am sick of ordering stuff through the mail and seeing "made in China" on everything. </div></div>

Probably the brands mentioned by Chad are good.

I tap a bazillion holes in pistol slides.
Over a couple years I have found that Greenfield EM-NI taps have consistently worked the best and lasted the longest for me.
Other applications may/will have different results.

 

[Bryan27]

Re: Please Educate Me on Tap Life

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: C. Dixon</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 671RTO9513</div><div class="ubbcode-body">The old Pollock that taught me more than I can remember about toolmaking always used kerosine on aluminum, and he did a bunch of work with it.

Hog lard is the best thing to stop files clogging when filing barrels lengthwise prior to polishing on octagon and shotguns. It's kinda messy but works great. An English barrel striker taught me that.

Also, I have surface ground aluminum with hog lard. Use a fairly open wheel and keep it slathered with lard. The al can be stuck to the table with double sided tape. Messy but works.

</div></div>

Medium CA (superglue) has worked for me in the past with grinding AL. Toughest part is getting the chuck really, really squeaky clean prior.

Few things suck more than watching a wheel explode as a part gets shot out of a surface grinder. (I made a mess once a long time ago grinding a set of 4 bolt main caps for a SB chevy.

Spent the rest of the day truing a wheel and grinding the dents out of the chuck.

<span style="color: #FF0000">Be careful. A grinder is the most dangerous machine in a machine shop.</span>

</div></div>

Yeah, I'd agree with that! I was taking a machining class at night a few years ago, working on one of the class lathe projects. Another student was using the surface grinder about 10 feet behind me. I was in my zone doing some threading when all of a sudden BOOM!! peices of the grinding wheel went flying! Apparently he was trying to take a little too much off his peice, cracked the grinding wheel under the stress and with it going a couple thousand RPM's chunks went flying. Lucky nobody got hurt.