# Snap!!!



## cessna (Jan 25, 2011)

The sound of the tap (2-56) half way through the last hole on an intricate part. What are the secrets to tapping brass with small taps? The hole is only 3/16" deep, I back it out and blow clean part way thru, is there a recommended taping fluid to use with brass?
Terry


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## don-tucker (Jan 25, 2011)

Although brass is a relatively soft metal I found the taps ,files, lathe tools must be extra sharp ,the use of a drop of paraffin when tapping also helps,if I have new taps or files I try to keep them for brass if possible.
Hope that helps a bit.
Don


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## tel (Jan 25, 2011)

I always work brass dry. 1/4 turn forward, 1/2 turn back is about all I can offer. Works for me.


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## Tin Falcon (Jan 25, 2011)

Taping 101
1) buy a good quality tap
2) buy a tap made for cutting threads 
 a) spiral point for through holes
 b) spiral flute for blind holes. 
 c) four lute hand tap. best saved for thread chasing
production taps do not require the constant chip breaking that the hand taps do. 
keep sharp I an considering a slip stone to touch up taps. 
Use a tap guide (several styles available) 
a tapping fluid also helps. Moly D has a good rep recommended by the greenly rep but IIRC will discolor brass. 
Tin


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## peatoluser (Jan 25, 2011)

The moment I feel a small tap going tight I back it out and change from a taper to second or plug tap, scew it in to cut a couple of threads, then change back to the taper tap. I have a few tap wrenches so have them set up ready. Slow and long winded but a lot quicker than staring at a broken tap wondering what the hell i'm going to do now.
peter


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## gbritnell (Jan 25, 2011)

It's amazing to watch a CNC machine power tap holes. The spindle is turning, it approaches the job and then in it goes, reverses and backs out. 
 What I'm getting at here is that a tap will take quite a bit of twisting load without breaking. I have found that most of the time I have ever broken a tap is when I'm turning it back out. It gets bound up in the chips and just the slightest twist and push of line and the tap will break. 
 My remedy for reducing small tap breakage, 0-80, 1-72, 2-56 etc is to use a small chuck to hold the tap. It seems if you use a tap handle, even a small one, you have the extra leverage of the T handle and that can cock the tap, even unknowingly, and break it.
 Although brass is a seemingly easy material to cut (360) it takes a sharp tap or tool to cut it cleanly. Personally I don't use a lubricant on brass. If you have compressed air handy try to blow the chips out when the tap gets tight. 
gbritnell


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## Mainer (Jan 25, 2011)

Brass can be a problem to tap. It feels as though the brass expands slightly from the pressure of cutting, then closes down around the tap to hold it. I've found that a wicked sharp top quality tap with as little surface area as possible (probably 2 flutes) seems to work the best for me.


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## George_Race (Jan 25, 2011)

I had a lot of problems with small taps in both brass and aluminum. Most of the time a tap would break when being turned out. All of the comments above make common sense and probably will help you sort out your particular situation.

For the most part, I solved my tap breaking problem by buying a small tapping stand. The one I got is from Micromark, their "MicroLux Tapping Fixture." At the same time I also got their "Quick-Jaw Vice."

I now can do very small threaded holes, down to 00-80 or 00-90, without tap breakage. I do use a drop of tapping oil to help. I think the main reason it helped me is that I can no longer "lean" the tap over as I turn it back and forth. I think that every time I broke a tap I was probably putting side pressure on the tap handle as I reversed the direction I was turning it. The Tapping Fixture also seems to let you "feel" how the tap is working much better than a T handle or pin vice. I never use the crank on the wheel, but simply turn the tap with my fingers on the edge of the knob, or sometimes just by turning the smaller area at the base of the knob.

Taps just don't like to be bent so they seem to resist by breaking off in the hole. Hope this helps,
George


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## Mainer (Jan 25, 2011)

One of these http://www.waltontools.com/products/spindle-charts.htm helps a lot. I've found that it is worth it to get the genuine Walton. An import copy I tried didn't hold the tap concentrically.


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## Metal Butcher (Jan 25, 2011)

I broke quite a few 4-40 taps in the past with my bad habit of power tapping. I would apply downward pressure with the quills spider handle and jog the power switch. It worked 'almost' all of the time if the tap didn't bottom out. Laziness got the best of me every time

I have good luck with the smaller sizes due to my fear of using hand taps, and hand tapping, using the dreaded 'T-handle tap breakers'. I avoid problems by focusing on the three issues listed below.

Rigidity;
I keep the tap rigid and assure its concentric to the bore by guiding it the same set-up and with the same chuck that just drilled the hole. I lock a one inch disk to the tap with a set screw, and use the jaws of the chuck (slip fit) to guide the taps shank while I screw the tap in with two fingers. Every time I started a tap as a prelude to finishing up later at the bench, it ended in disaster.

Chip removal;
Using hand taps requires a keen sense of feel to 'know' when its time to back out and clean the chips off of the tap. If I waited too long the tap would jam and break on the way out. I never broke one on the way in. The best solution is to avoid dealing with the chips in the first place. Drill the hole through, or a deeper hole, and use a gun tap. For blind holes buy and use a spiral flute tap that draw out the cuttings and eliminate the build up of chips. If I have to use a hand tap, I focus on feeling a slight indication that the chips are starting to put a drag on the tap and back it out immediately. Yes its time consuming, but its still faster than starting all over by making a new work-piece! 

Patience;
I take a smoke break, or do a few minutes of clean-up to relax and clear my mind before I drill and tap holes.
If I'm in a hurry, a quicker way to break a tap would be to stick it in a vise and tap it with a hammer. At least the work-piece would survive! Rof}

-MB


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## compspecial (Jan 25, 2011)

I'm not sure if we are talking about high speed steel or high carbon steel taps here, I have a few carbon steel taps which I bought coz they are less than half the price of HSS. I haven't broken any yet but I'm sure it would be very easy to do,and very frustrating  carbon steel seems to be just as hard but twice as brittle as HSS and brass is slippery stuff, seems to spring closed again after the tap turns. serves me right for buying cheap stuff  I think aiming for a maximum of 75% thread engagement is a good idea too because its claimed to be just as strong as a deeper thread
               Stew


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## GWRdriver (Jan 25, 2011)

George_Race  said:
			
		

> Most of the time a tap would break when being turned out. For the most part, I solved my tap breaking problem by buying a small tapping stand . . . .


Go back and have another look at George's post. I have had the same experience and every word of it is spot-on. Reducing or eliminating non-axial stress on the tap, in either direction, is the single thing that will reduce (if not eliminate) tap breakage. Of course there are those who have to force things and simply push the tap beyond its limits, but as George says the tapping stand allows one to feel very clearly what the tap is doing. I made my own tapping stand from some scrap steel and a Jacobs drill chuck, and I literally went from breaking a tap every few weeks (or so it seemed) to breaking one every few years. This was a tool I realized I should have made (or bought) long before I did.

A couple of comments about the Micro-Mark Microlux Tapping Fixture, which seems to me to be a bargain for the price, . . . I made a calculated guess and installed a 0" to 1/4" drill chuck on my tapping stand. Consequently I found that with hand-turning with a knob (such as the Micro-Mark has) my practical limit of repetitive wrist torque was 1/4" threads, so the 1/4" chuck size is perfectly suited for my model work. I have a single 1/4" hole centered in my table and I've never had a need for anything larger, some things I thread would fall through it. I've also never had the need for T-slots or drilled screw-down holes. That's not saying I won't someday, but so far a smooth table has done the job.


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## kustomkb (Jan 25, 2011)

A guide like this helps me keep taps perpendicular;


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## Troutsqueezer (Jan 25, 2011)

Starting with a brass rod, I made a small hand held chuck to hold the tap. The handle end is round, knurled and about the diameter of a nickel. I use this for 2-56, 4-40 and sometimes 6-32. The small diameter of the grip gives good feedback as to the pressure I am applying, going in or backing out. I've yet to break any tap in this hobby. Lucky, I guess.


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## mklotz (Jan 25, 2011)

I agree that bending, not torquing, is the major cause of tap breakage. A tapping machine is fine but every tapped hole requires you to drill a hole first. As soon as the hole is drilled, you're sitting in front of a perfectly aligned tapping machine. Just make some of the tools shown in this thread...

http://www.homemodelenginemachinist.com/index.php?topic=464.msg2829#msg2829

and your bending problems will be over.

Beyond that, increase the percentage depth-of-thread so you can use a larger drill. I've provided the formula for this on many occasions and it's part of the DRILL program available on my page.


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## jpeter (Jan 25, 2011)

You guys will think I'm crazy but I like tapping with a battery powered drill. Advantage; the chuck will slip if the tap bottoms out or turns too hard. I can reverse the drill to back out too. Once backed out some, forward the drill and drive it in some more. Most small taps I've broken is because I've bottomed them out when turning them in by hand.

I also made from Internet plans a tap burner which I power down with my mill down feed. I feed it about 0.1 inches per minute and still use the previously made threads.


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## Ed T (Jan 25, 2011)

IMHO, one of the biggest contributors to tap breakage is getting the tap started off axis to the hole. As the tap proceeds into the hole, you are trying to force it to go around a corner. The tip of the tap it trying to follow the drilled hole, the body of the tap is trying to follow the threads already cut and something's gotta give. Backing in and out helps to resolve this conflict and I have often noticed that once everything is lines up, the tapping goes quite easily. I also "cheat" sometimes and go a bit larger on the tap drill size. For most of the miniature stuff we're making thread strength is not a big deal and a little relief on the amount of metal being moved makes life simpler.


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## Russel (Jan 25, 2011)

When tapping small holes, I use a little aluminum disk with a hole in the middle and a set screw mounted directly on the tap. I've added some grip to the disk tap handle since this photograph was taken. The 1/4 turn forward 1/2 turn back method seems to work best for me with the end of the tap loose in the chuck to act as a guide.

I really like mklotz's tools. I'm thinking that I should make a cylindrical guide that can be gripped in the chuck with the end of the tap going through the middle for support.


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## Metal Butcher (Jan 25, 2011)

Russel  said:
			
		

> When tapping small holes, I use a little aluminum disk with a hole in the middle and a set screw mounted directly on the tap. I've added some grip to the disk tap handle since this photograph was taken. The 1/4 turn forward 1/2 turn back method seems to work best for me with the end of the tap loose in the chuck to act as a guide.



Russel, That's exactly what I made and use. I made three 1/4" thick disc's, a 1", 1-1/2", and a 2" in diameter. I added a light knurling on their out side edge. Since all my smaller taps have the same diameter shank, one disc is all that's really needed. They are quick and simple to make and use. Nothing is sticking out to bump into, or get hooked on and break a tap. I usually use the one inch disc on taps smaller than 4-40. Its nearly impossible to break a tap if you rotate the disk between your thumb and fore finger. 

Sorry guys, but I don't understand why any one would need to buy some special hand tapping gizmo to replace the chuck on their lathe and mill. Sounds like more work to me. After drilling a hole I simply replace the drill with the tap and finish up in less than a minute before moving to the next location. It doesn't get any easier than this.

Enlighten me if you have a quicker and safer method.

-MB


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## doc1955 (Jan 25, 2011)

I personally use MolyD on any tapping I do and some drilling. It is messy stuff but works good. Other than that I have to say most of my broken taps have come from being in a hurry and not backing up as much as I should or not keeping the tap perpendicular to the work piece.


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## shred (Jan 25, 2011)

For the 2-56's I think there are 3 keys:

-- Tapping guide of some sort so it's absolutely straight. Very important with small and deep holes.
and
-- Correct-size hole. 50% thread engagement works fine for 99% of what a 2-56 will be called upon to do and is a lot easier to tap than a 75%
-- Good taps. Doesn't have to be hand-honed by swiss gnomes, but the lowst priced ones can be trouble.

My tap wrench is a couple inches of 1" dia rod knurled with the tap held in one end and a 3/16" sliding-fit guide shaft out the other. Like the disks, but with a built-in guide to grab with the chuck. You can only turn it with fingertips and get a good feel for what's going on.


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## siren (Jan 25, 2011)

The advice on this thread is exactly what I needed. I also just broke a 2-56 tap after getting a little too full of myself after the first one.

One question about "quality" taps. I'm a complete newbie and when I go on the Enco website to buy some taps, I'm completely overwhelmed. Up to now, I've just been picking them up at the hardware store. One choice; not much thought. Don't mean to hijack this topic, but what do you guys use for your taps?

I did take a look (albeit rather after this post) at the whole thread that mklotz linked. Still am interested in what the experienced members have chosen for their preferred taps. I know this is a bit like asking which beer is best (Kneitinger Bock--only available in Regensburg, Germany, BTW), but I'm interested to hear why people have made the decision they've made. Hopefully it can give me somewhere to start (so that I can actually HAVE an opinion on the matter). Thanks!

Brad


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## shred (Jan 25, 2011)

I've used a number of the Enco taps, often the on-sale "Made in USA" coated spiral-point ones. OSG and Cleveland have also been good. The "Interstate" and "Import" ones are lower quality-- ok for occasional use in odd sizes, but I don't like them for regular use.

I also have a Harbor Freight HSS Tap & Die set I got way back when. They're marginal-- on par with the low-end Enco taps, but it's nice to have a whole imperial/metric set for odd jobs that come up (The HF carbon steel tap-n-die set was total junk). 

With any small taps, get two. That way you won't be tempted to push one after it starts to get cranky, and if you do break one, you also aren't dead in the water.

(now WTH do 2-56 taps always cost more than the next six sizes up?)


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## Metal Butcher (Jan 25, 2011)

siren  said:
			
		

> The advice on this thread is exactly what I needed. I also just broke a 2-56 tap after getting a little too full of myself after the first one.
> 
> One question about "quality" taps. I'm a complete newbie and when I go on the Enco website to buy some taps, I'm completely overwhelmed. Up to now, I've just been picking them up at the hardware store. One choice; not much thought. Don't mean to hijack this topic, but what do you guys use for your taps?
> 
> ...



I have 'some' experience if that counts.

I buy all of my taps from Enco. I use imports and USA with equally good luck. And I like to use 'gun taps' to avoid having to back out hand taps to clear them of chips, provided that the hole is deep enough to store the cuttings or a through hole to push them out. The gun taps (spiral point) seem to cut a little better than a hand tap. On a deep hole especially in aluminum I like to use a spiral helix tap that pulls the cuttings out of the hole. In and out, and I'm done.

Best beer was 'Ontario Strong' a Canadian beer, or 'Zywiec' a Polish beer. Two bottles of either one and your face down on a beach in cottage country! I say 'was' because I gave up recreational drinking about five years ago.

When it comes to getting plastered or tapping a hole we all have 'proven methods'. *beer*

-MB


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## Dave G (Jan 25, 2011)

On a straight cut tap set, the ones with three taps in a set, theres a starter, a plug, and a bottom tap.The starter has the most taper to the cutting edge,and the bottom tap the least. Use the starter to start your hole, tapping as deep as it will go,
then finish with the bottom tap if the hole is a blind one. Be careful when reaching the bottom of the hole. these taps with most materials must be backed up like in the 1/4 turn forward, 1/2 turn back method to break the chip. If this isn't done the chip will build up andclog the flutes of the tap causing breakage. On CNC equiptment, gun taps or spiral flute taps are used.
Gun taps are for thru holes, the cutting edge is designed to project a continuous chip down and out the bottom of the hole.
Normally you don't back up a gun tap until you have reached the bottom of the hole. I use gun taps, if it is a thru hole, by power tapping in the drill chuck in the mill or lathe. Spiral taps are for production for mostly blind holes. The cutting edge is designed to shoot a continuous chip up out of the hole. I use these also, but they have a tendency to break when reversing direction. Very strong going forward, weak in reverse. I think the trick to tapping soft materials is to reverse the tap often out of the hole and clean the chips from the flutes. Buy good high speed steel taps and keep them from touching each other in the box to keep them sharp and when they feel dull, replace them. I hope this helps. Dave.


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## Lakc (Jan 25, 2011)

Tapping questions will always get a big response among machinists. ;D There has been much good advice already given, to which I would like to humbly add.

The smaller the tap, and more flutes, leaves less and less room for the chips to go. It doesnt matter if the chips are broken or not. Sometimes there is just no substitute for compressed air or flood coolant, except for backing the tap out completely to blow the chips clear. Very annoying, but if its Sunday night, or a complicated part, and you absolutely cannot afford to break a tap, pull the thing out every 3 threads if you have to. I have never had an unexplained tap failure in the first couple of turns. 

The local hardware store (ACE) sells pretty high quality taps, but now they have gone exclusively TiN coated. This is a *bad* thing for tapping aluminum! Dont use any type of titanium coating on a tool for aluminum. 

I try my darnedest to tap holes as soon as I drill them, and use the machine to keep the tap straight, taking any type of alignment problems out of the picture.


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## cessna (Jan 25, 2011)

Thanks for all the info to my problem, I have read and digested it all, I like the idea of the tap holder fitting into the same chuck that drilled the hole, I have made one up and will try as soon as new taps arrive.
Terry


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## rake60 (Jan 26, 2011)

*"The Book"* says you NEED a 70% thread. 
That means you use a #50 (.070") drill bit for a 2-56 tap.

A #49 (.073") drill bit would only give you a 56% thread.
For that -.0015 per side the world may cave in! Or *NOT!*

That very slight variance will make a difference in tapping.

I always use the next size larger drill for my projects and haven't had one
cause personal injury or property damage as of yet. 

Rick


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## mzetati (Jan 26, 2011)

I've made myself a hand tapper from an old B&D column I had no use for, and various scraps from the metal pile.
Marcello


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## Ken I (Jan 26, 2011)

Like Metalbutcher suggests - I tap using the same spindle that made the hole - put the headstock in neutral and turn by hand.

For small taps I use a pin chuck with a hex driveshaft - by holding the hex lightly in a drill chuck it can "float" so you don't crowd the tap. (Obviously a propper tap holder would be ideal - on my "to do" list.)

For blind holes you can hand roll a plug of beeswax or softened candlewax (add parafin) - this chases the swarf back up the flutes as it is displaced by the tap.

For larger taps I only start with the spindle and then go to a tap wrench.

Any tap started off-true will not really straighten itself - you'd be amazed at just how far off true a tap can tap the hole - this leads to it taking an inordinately large "bite" out of one side of the hole. Not to mention the problems of fit up with off true threads.

Squareness of tap to hole is the thing I take most seriously (all other good tapping practice and advice above taken as a given).

I have a number of toolrooms building machinery for me that make a habit of drilling all the holes on a mill (CNC or otherwise) and follow up with hand tapping - to save machine time. I have gotten so fed up with the results that I have banned them from doing so on my work - my drawings state this - out of square holes being grounds for rejection of the parts. If I catch anyone doing it - its asskickking time.

Ken


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## GWRdriver (Jan 26, 2011)

mzetati  said:
			
		

> I've made myself a hand tapper from an old B&D column I had no use for, and various scraps from the metal pile. - Marcello


Marcello,
You've given me an idea for a solution to a recurring problem . . . a compression spring to stop the spindle dropping down unexpectedly. Brilliant!


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## mzetati (Jan 26, 2011)

GWRdriver  said:
			
		

> Marcello,
> You've given me an idea for a solution to a recurring problem . . . a compression spring to stop the spindle dropping down unexpectedly. Brilliant!



That spring can get dangerous for the taps, when tapping items which are 'heavy' in relation to the tap diameter, especially in holes near their edges.

Marcello


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## Lew Hartswick (Jan 26, 2011)

rake60  said:
			
		

> *"The Book"* says you NEED a 70% thread.
> 
> Rick


Rick are you sure it says "NEED" or is it "FOR" a 70 % thread. 
  ...lew...


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## rake60 (Jan 29, 2011)

Lew Hartswick  said:
			
		

> Rick are you sure it says "NEED" or is it "FOR" a 70 % thread.
> ...lew...



You are correct Lew. Thank you for the clarification of my comment. 

It does in fact say, *"FOR"*.

I have never seen a *"NEED"*, *"FOR"* a 70% thread in hobby engineering of a steam engine.
If it is an internal combustion engine that 70% may come into play. Or not at all.

Rick


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## wizardofwood (Jan 29, 2011)

A tip I heard from an old toolmaker was use kerosene for tapping aluminium
and if tapping brass, either dry or use turpentine.


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