Breaking fine thread taps... Grr...

Parke1

Parke1

Joined
Feb 11, 2003
Messages
1,862
Hey everyone,

Well, I'm waist deep in my third knife project, and I seem to have run into a problem. I can't for the life of me get a tap to work right.

Here's the situation. I'm working with cold-rolled, annealed 1095 that's 5/32" thick. I drilled four holes in the tang area of my blank, using the correct size bits (#25) and plenty of cutting oil. The holes drilled perfectly fine. My problem is that I've now snapped off FOUR 10-24 taps in this steel. These are "good" taps that were all brand new, Vermont American brand.

So where can I get a couple really really strong taps in this size (and also 6-32)?

I really don't think I'm breaking them with an error in my technique, since I have no problems with any other sizes or materials... I turn them in a bit, then back them out, and repeat until I'm fully tapped. Suggestions? Comments? Concerns? ;)

Thanks in advance for the help!
-Parke1
 
well here is a common problem . first things first to get the broken tap out of the hole.. use a solid carbidedrill bit about a 1/16 size and drill as colse to the center of the broken tap as you can ,your using a 3 flute tap so once you drill through the center of it it should come out by itself .next after the tap is out Go to a Cutting tool store and buy a real tap id recomend a split point high speed steel one !! Vermont America are Hardware store tap's and not very good !! before you try to tap anymore on this you might want to anneal it just in case you work hardened the holes by drilling too fast . im not trying to be a ass here but ive used a lot of crappy tap's and broke more of them than ill ever addmit to!! use a good tap slow and steady with a bit of cutting fluid and you will be ok . get in a hurry and snap.
 
Tap-Eze or some other metal cutting lube helps quite a bit, whether you are using ana auto tapper like a Procunier, a nice manual tapper like Jeff Higgins makes/made, or a manual tapper like you get at Sears. Your breaking is because of either too much friction and are twisting the tap to break, or more likely allowing the angle of the tap to change by letting a part being tapped move or the tapper move out of line with the hole.
I've broken plenty so I am sharing experience, not preaching.(smile)
 
I've threaded a lot of holes. These days, I mostly thread mill them, but the technique I use when I do tap them will work for you.

Don't use an oversize hole, use the correct sized hole for the material you're threading or you will get a weak joint from inadequate thread engagement.

Use Castrol molydee. It is black, stinky, and you don't break taps with it. MSC sells it. A bottle will last years.

Get a T handle type tap holder that goes in your drill press. That way you can tap in the same setup you drilled. This keeps things aligned, which is the main cause of hand tap breakage.

I often don't need to back out the tap. I certainly don't sweat a 10-32, I just crank it out with no problems using an aligned setup, sharp tap and MolyDee.

Very small taps benefit from rigid CNC tapping or the use of a tapping head attachment because they work better at higher RPM, which is not feasible when hand cranking it.
 
good info above here
I use a Makita variable drill,
right in and out being very careful keeping it lined up
cranking it side ways will brake it as fast as any thing next to a dull tap and dry. I wished I could buy Tap free still :grumpy:

also if you do want to back it off while hand tapping, don't wait until it binds on you, it's to late then.. I have mills and drills and all the play tools but never bought a tap-o-matic ,, never had to..
you can also start a tap straight by chucking it up in your drill press and hand feed it (power off) once started use your tap holder the rest of the way..
just 2 more cents..:)
 
Dan, so you are saying you can tap threads into a hole using the drill press? Do you use it powered or unpowered all the way thru? I thought you were supposed to go in a little and then back off and keep doing that til it is all threaded?

Nathan what does that drill press T-handle look like?

Just curious since i seem to keep breaking taps also :confused:
 
You also suppose to release drill's return coil spring. That way you have weight of drill spindle pressing down on your tap and don't have to push it manually.
 
Terry_Dodson said:
Dan, so you are saying you can tap threads into a hole using the drill press? Do you use it powered or unpowered all the way thru? :confused:
Click to expand...

Terry
as said hand feed it (power off)
this is just to start the tap straight if you have no other way.. and can't do it by eye.

turn the spindle by hand feeding it in,,

Terry_Dodson said:
Dan, I thought you were supposed to go in a little and then back off and keep doing that til it is all threaded?

:confused:
Click to expand...

backing it off every so often yes if you have to.. if it's powered in you don't have to.. starting and stopping the tap is hard on taps, taping by hand you have no choice you have to stop it about every 1/2 turn..:(
 
Alexmin
I don't release mine but I know the feel of it.. but that's me on Mine, yes that will sure help with the small taps..

one of the tee's you can get has a hole in the back for a live or dead center
if you use this type with a center you still can be off center if you've moved the part after drilling it.
if you chuck the tap up in the chuck itself an then line up your part with the tap then clamp your part down you'll be good to go..with either type you use.. or the way you use them.
also
look up Higgies (Jeff Higgins, one of our own here) tapping rig he was making and selling those are nice for small taps..
 
Higgy, Fitzo ....whats the difference....All you New England fellers look the same.
Thanks Mike, Yes it was Jeff's tool.
Stacy
 
bladsmth said:
Higgy, Fitzo ....whats the difference....All you New England fellers look the same.
Thanks Mike, Yes it was Jeff's tool.
Stacy
Click to expand...

About 100 pounds and the accent, for starters. Here in the flatlands of the Chicago area of New England we sound a bit different. :D

YW, Stacy! :)
 
"
Terry_Dodson said:
Thanks for the link. It looks like you still turn the T manually, it just keeps it lined up right?
Click to expand...
"


Yeah, it keeps it lined up, which prevents 99% of tap breakage and improves the thread quality over an "eyeballed" hole.

I also use this:

http://www1.mscdirect.com/CGI/NNSRIT?PMAKA=09491002

It at least holds the tap vertical while you're threading, though I'm of the opinion there is no substitute to tapping in the same setup as the hole was drilled, before moving the part.
 
Not really trying to be a smartass, but that is the first time I have seen the words "good" and "Vermont American" used in the same sentence.
 
winstonknives said:
Not really trying to be a smartass, but that is the first time I have seen the words "good" and "Vermont American" used in the same sentence.
Click to expand...

Funny...............but true ;)

Most are 4 fluted taps :thumbdn: terrible for hand tapping. Get a good 3 fluted split point as mentioned earlier. 2 fluted taps are great to. I can't remember the last time I broke a tap larger than a # 6, a 10-24 should power right through annealed 1095. It has to be the vermont :)
 
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