# Help tapping small threads, please



## almega (Dec 22, 2018)

As a relative newcomer, I am seeking help with the best way to tap for small sized machine screws.  I am looking at a need to tap a few holes for 4-40 in hot rolled steel and when I look at the size of the tap I am thinking that it could snap right off and be a real pain to remove from the hole.  Are there special lubes that I should consider and will I need to build a tapping stand?


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## stevehuckss396 (Dec 22, 2018)

Use a good quality tap. Don't use an asian tap. When you rotate the tap it should feel crisp like its cutting and not smearing the metal. When you back the tap off it should be free to rotate and not tight in the hole. 

Consider a lower percentage of thread enguagement. Most tap charts have drill sizes spec'd out for a 65% - 75% thread with a #43 drill. Fine for aluminum, brass, Etc. You could drill bigger with a 42 or 41 even and still have a good strong thread @ 50%

Use lube like tap magic or some of the wax based lubes. 

That's all i got!


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## almega (Dec 22, 2018)

I have Vermont American, made in USA taps.  Will those work or should I be getting something else?  They come in sets with #43 drill but you think a #42 or #41 might be better for the hot rolled steel.  From the size charts it appears a 3/32" would work too.  I will give it a try.  Thanks.


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## RM-MN (Dec 22, 2018)

almega said:


> I have Vermont American, made in USA taps.  Will those work or should I be getting something else?  They come in sets with #43 drill but you think a #42 or #41 might be better for the hot rolled steel.  From the size charts it appears a 3/32" would work too.  I will give it a try.  Thanks.



I bought a couple of those Vermont American tap and drill sets for 10-24 threads.  Broke every tap.  Bought a better taps on Ebay and learned to throw away that included drill from Vermont American and use a slightly bigger drill bit and the breakage was over.  For most applications the slightly lower thread depth will have plenty of strength.


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## almega (Dec 22, 2018)

Thanks, good to know.  I will use the larger drill and maybe save the #43 for aluminum or brass.  Would I use the same tapping fluid for aluminum and brass as I use for steel or iron?


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## BaronJ (Dec 22, 2018)

Hi Almega,

If you haven’t got a tapping stand, then use your drill press !  Remove the belt so you can feel the tap.  The larger drill will also help.

FWIW, I'm about to tap a couple of M1.20 X 63 tpi, in 1 mm diameter holes, fortunately in hard aluminium bar.  The threads are so fine I can barely see them without magnification.  I'll be using kerosene as a tapping fluid.


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## mgb (Dec 22, 2018)

I made a variation of this.
http://www.clickspringprojects.com/tap-and-drill-extenders.html

Drill out the holder, and fix the tap in with superglue. A short length of silver steel in the chuck, with the holder a sliding fit allows you to have a a great feel of the tap working. If you over do it, the glue bond usually breaks first.
Ideally, drill the hole first, and with the table locked off proceed to tap the hole with the same settings.

Worked for me on 2mm and 7BA taps.


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## ShopShoe (Dec 22, 2018)

Everybody so far has said the best advice, but I want to add that you need to reverse the tap more frequently than you think to clear chips. In steel, you may also want to completely remove the tap from the hole, clean the hole and clean the tap, then re-lube and continue. With good feel, you should be able to tell when the "going is tougher."

My unfortunate experience has sometimes been to start to feel more resistance, then say to myself: "The hole is deep and it should be harder. Just a quarter-turn more..." and SNAP. Patience takes longer but ends on a happier note. 

__ShopShoe


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## olympic (Dec 22, 2018)

ShopShoe said:


> My unfortunate experience has sometimes been to start to feel more resistance, then say to myself: "The hole is deep and it should be harder. Just a quarter-turn more..." and SNAP. Patience takes longer but ends on a happier note.



How apropos! This is exactly what I did yesterday with a 6-32 tap in a piece of aluminum (very sticky material). Fortunately, I had room elsewhere on the piece, and the broken tap hole will be hidden when things are assembled. I did, though, have to go to a 4-40 tap to accommodate the bolt head.

Just remember, tapping stand or drill press, plenty of lube, light touch, frequent backing out to clear, and PATIENCE (which in my case I have not got)....


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## almega (Dec 22, 2018)

I think my next project before I move on and tap the holes for the current project had better be to build a tapping stand.  Thanks for all the good advise.  It is very nice to have a resource such as this, especially for those of us who are new at it.


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## Aerostar55 (Dec 22, 2018)

almega said:


> As a relative newcomer, I am seeking help with the best way to tap for small sized machine screws.  I am looking at a need to tap a few holes for 4-40 in hot rolled steel and when I look at the size of the tap I am thinking that it could snap right off and be a real pain to remove from the hole.  Are there special lubes that I should consider and will I need to build a tapping stand?


I use a tapping s


almega said:


> As a relative newcomer, I am seeking help with the best way to tap for small sized machine screws.  I am looking at a need to tap a few holes for 4-40 in hot rolled steel and when I look at the size of the tap I am thinking that it could snap right off and be a real pain to remove from the hole.  Are there special lubes that I should consider and will I need to build a tapping stand?


tand from Harbor Freight @80 bucks it was a good investment.  Also use Tap Magic fluid. Before starting to tap I blow out any chips in the hole wit compressed air.  I keep the air gun close and blow out the hole and the tap frequently, adding fluid after cleaning the hole each time the tap is backed out.


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## happy hooligan (Dec 22, 2018)

If at all possible, I use the drill press to tap holes. I have used Vermont America taps almost exclusively simply they're available locally and I haven't really had any problems.  I think the key to tapping with small taps is to keep the tap straight and backing it out frequently to clear it.


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## tornitore45 (Dec 22, 2018)

> Remove the belt so you can feel the tap.


Good advise, however once you get the feeling mastered, turning the chuck get old fast.  By leaving the belt and pulling on it one makes quick work.
Building a tapping stand is a waste of time.  If you have a drill press there are better ways:
1) For medium taps #8 t0 3/8
Put the tap in the hole and turn backward 3/4 turns. That centers the hole under the tap.
Clamp the part in position so it does not turn
One hand on the lever and one on the belt to turn the tap
Easy to go forward and backward.
2) For smaller taps
Make a tap holder 3/8 or 1/2 diameter about 2"-3" long, knurled 1/2 way.  2 radial set screw to drive the tap, do not need to be tight, just snug
Insert holder into chuck but do not tighten, free to rotate and move up and down
Set table height or column lock so that the tap and holder stay in the chuck without falling out.
One hand hold the part, free to autocenter. Other hand rotate the tap-holde/driver on the knurled section, with two fingers. 
The driver being so small in diameter limits the torque and the finger have great sensitivity and feeling.
I used to break taps until I learned what broke them and stopped doing it.


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## kuhncw (Dec 22, 2018)

You might also look into thread forming taps such as those made by Balax or others.  They work great in aluminum, brass, and soft steel.  Forming taps do not have flutes like taps that cut the thread, so they  are less likely to break.  You do have to follow the manufacturer's recommendation for tap drill size as the forming taps require a slightly larger hole.  Forming taps do not generate chips which is another plus, in my opinion.

Chuck


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## almega (Dec 22, 2018)

tornitore45 said:


> 2) For smaller taps
> Make a tap holder 3/8 or 1/2 diameter about 2"-3" long, knurled 1/2 way. 2 radial set screw to drive the tap, do not need to be tight, just snug
> Insert holder into chuck but do not tighten, free to rotate and move up and down
> Set table height or column lock so that the tap and holder stay in the chuck without falling out.
> ...



Tornitore45 do you have any photos of what you are describing.  It would be good to use the drill press instead of having to build another tool, especially if it will do the job.


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## MachineTom (Dec 22, 2018)

A Tapping stand is great, but for a #4 screw to much torque. I use tapping blocks, for that size tap.  a 3/8 block in a mill or DP, drill a Body size hole, a tap size hole, and a 4-40 tapped hole. Now you can  get a hole started straight, then position the tap in the block over the hole and thread as normal, as the tap is not that long you will need to remove the block an finish to depth. You can drill a hole the body size of the tap itself, half the depth of your block then a tap size hole the rest of the way, now the tap should have enough to do the hole.

I like a spiral FLUTED tap, expensive  but much less torque needed to tap in tough material. A spiral [point tap work great on thru holes, the chips are pushed out ahead of the tap. Both of these are HSS, not crappy Carbon steel.


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## Cogsy (Dec 22, 2018)

Just for completeness I'm going to put down what (so far) works for me. My drill press gets very little work and I've never used it for tapping. I drill my hole using my mill, then without disturbing the setup I change to a tap in the chuck. I rotate the chuck by hand, with manual downfeed, until I have the tap engaged for a few threads and it will stay aligned. Then I undo the chuck and use either a tapping handle (above about 3mm tap size) or a simple handwheel for the smaller sizes. Using this method, with appropriate lubricants, I've tapped down to 0-80 in drill rod, brass, bronze, aluminium and steel. I also back the tap off a LOT - like every 1/2 turn at the most for small taps. The majority of my taps are cheap Asian stuff and all of my tiny taps came out of a $40 Chinese 'watchmaker' set. I probably shouldn't say this out loud, but I have not yet broken a tap since I got into the hobby in 2012. Your mileage may vary.


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## mnay (Dec 22, 2018)

If you can get them, two flute taps are stronger and harder to break


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## blanik (Dec 23, 2018)

almega said:


> As a relative newcomer, I am seeking help with the best way to tap for small sized machine screws.  I am looking at a need to tap a few holes for 4-40 in hot rolled steel and when I look at the size of the tap I am thinking that it could snap right off and be a real pain to remove from the hole.  Are there special lubes that I should consider and will I need to build a tapping stand?


Look for High Speed Steel Taps - not the cheaper High Carbon Steel taps.  With small size taps, it is very important to use exactly the right size drill - just a tiny bit too small a hole will be disastrous, and just a tiny bit too large a hole, and the thread will be weak.    Look up the right sized tapping drill size and then buy the exact size specified.  Don't just grab the nearest size that you have on hand.

I do a lot of tapping of small size threads (typically from 1mm threads up to 2.5mm).  The easiest way to break a small tap is to bend the tap.  The next easiest way to break a small tap is to fail to back the tap out of the hole every turn.  In one turn and back a half turn to break the chip works well.

What I do to make sure that I don't bend the tap and break it, is to use a purpose make Tapping Jig.  If you only use small taps occasionally, use the chuck in your drill press (or small mill, or small lathe), to hold the tap, and to keep the tap in line with the hole.  Use your finger tips to turn the chuck with a very loose grip so that you can feel what the tap is doing.  When I use my drill press, I remove the belt, so that the spindle rotates very easily.


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## DJP (Dec 23, 2018)

No one has offered advice on how to remove a broken tap which is sure to happen. All it takes is one dull tap. It should be part of this topic, in my opinion.  Perhaps we should expand the topic to sharpening taps. It should be possible to grind a bigger slot. I have made thread cleaning taps out of bolts with slots that I ground by hand. It worked well enough for my needs.

Any thoughts?


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## olympic (Dec 23, 2018)

DJP said:


> No one has offered advice on how to remove a broken tap which is sure to happen. All it takes is one dull tap. It should be part of this topic, in my opinion.



Great idea! Advice on removing broken small taps (say, 4-50 down to 0-80) would be really welcome (not that I personally have ever broken one)).


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## almega (Dec 23, 2018)

Since the material I need to tap is only 1/8" thick and will be through tapped, what about using self tapping screws to create the threads?  Those are much less costly than the taps and though they might only be good for one or two threads, they might be more cost effective in this case.  Thoughts?


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## goldstar31 (Dec 23, 2018)

DJP said:


> No one has offered advice on how to remove a broken tap which is sure to happen. All it takes is one dull tap. It should be part of this topic, in my opinion.  Perhaps we should expand the topic to sharpening taps. It should be possible to grind a bigger slot. I have made thread cleaning taps out of bolts with slots that I ground by hand. It worked well enough for my needs.
> 
> Any thoughts?



sharpening taps:-
Are there many home built machines which are capable of such a thing?

broken taps:-
I've got a broken off 2.5mm screw in an insert type milling cutter.  Too far in to drop a spot of weld from a Mig welder. Maybe I should try wearing the broken stud away with a Dremel and diamond grit and once out fill with weld, drill and re-tap. All this stuff about reversing a drill and hoping for miracles- in that size have proved hopeless. 

Then I re-read Prof Chaddock on his Quorn and he could make 1/10th diameter milling cutter-- but couldn't re-sharpen them. He also had problems.

One thought that came to me was drill or D bit the exposed threads away  and knock the offending it out and Mig weld new metal in , drill and re-tap.

Maybe someone will comment. 

Norman


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## Ken I (Dec 23, 2018)

almega said:


> Since the material I need to tap is only 1/8" thick and will be through tapped.  Thoughts?



Here's a piece of advice - the problem with tapping is we generally turn the taps way too slowly (for good reason) but that increases the torque.

So I use my cordless drill and blast through (add one drop of HP lube) on small through (not blind) holes. (Set the clutch to the bare minimum + hope.)

Get it wrong and the tap will break - I tapped 200 consecutive M2 holes through 2.5mm thick 316 stainless without breaking a single (spiral point HSS) tap.

Not for the faint hearted or inexperienced.

A reversible tapping attachment c/w slipping clutch that won't snap the tap and can be instantly reversed in and out as required is the answer - but I haven't yet found one for really small taps - does anyone out there know of such a beast or better yet a design ?

Regards,  Ken


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## larryg (Dec 23, 2018)

I have at times when drilling and tapping small holes on the mill released the drill chuck, held in a 1/2" collet, and chucked up the tap and turned the chuck that is guided by the collet.

lg
no neat sig line


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## Naiveambition (Dec 23, 2018)

For broken taps, solid carbide will drill right through.  After this there a plethora of options,   but you can chip it away , they break away rather easily, and if you can take out the center with drilling u can pick out just the threads, or maybe get enough bite for a screw extractor.   I have even drilled out the whole tap and made a plug to suit, then Re tap.   
Here are the ones I have.  They were bought to drill thru hardened steel and are straight flute.


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## savarin (Dec 23, 2018)

I threw together a very simple edm for my broken tap removal using Derek Lynas's circuit that used to be on this website but I cant find it here now.
I can post the circuit if wanted.
This version is a better version
http://mikesworkshop.weebly.com/a-spark-erosion-apparatus.html
Mine is not a build to be proud of as it really was just thrown together and would NOT pass the safety audits of today.
I drive it from an old stick welder transformer.
I has been a god send rescuing me from my own clumsiness breaking taps and also making tabbed washers in stainless steel.
It is not fast and can overheat the coil so 5 mins on, 10 mins cool down.
I usd a thin tig electrode the last time I used it to burn out a 6mm tap, straight down through the centre web and the three flutes just fell out.


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## mfrick (Dec 23, 2018)

When serving my apprenticeship I had a job taping several hundred 4-40 and 5-40 holes in mild steel plate 3/16" thick we kept the taps in cutting oil on a hot plate to keep them warm and limber which cut down on the breakage. So still today 50yrs latter I still warm up small taps prior to using them. 

Mike


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## goldstar31 (Dec 24, 2018)

Naiveambition said:


> For broken taps, solid carbide will drill right through.  After this there a plethora of options,   but you can chip it away , they break away rather easily, and if you can take out the center with drilling u can pick out just the threads, or maybe get enough bite for a screw extractor.   I have even drilled out the whole tap and made a plug to suit, then Re tap.
> Here are the ones I have.  They were bought to drill thru hardened steel and are straight flute.
> View attachment 106363



I'm talking about 2.5mm which means that one has to drill out the core which is less than 2mm diameter.
Again, what sort of rig will keep the drill central-- without it breaking as well??

Freehand is not an option for me, I'm partially blind and a wee bit over the hill or such things.

I've seen miniature welding sets with turret heads which might work but they are dental things and cost hen's teeth. 

Really, I'm just plain mean and should buy yet another replacement segmented cutter-- and live a little.

Meantime, off for Christmas amongst people who push stents into arteries and others who weld with these miniature things

N


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## abby (Dec 24, 2018)

I have to agree with Goldstar , break a very small tap and you will be unlikely to drill it out .
Best solution is to be very careful , I tap hundreds of holes from 10BA down to 12BA , admittedly these are all in brass or gun-metal.
I have found that the best method is by hand with the tap held between the finger and thumb in a pin chuck , squared visually.
This is a skill that has to be learned and I did break one or two taps before getting the "feel".
Practice is the key , try tapping some holes in a piece of scrap , never use more  force than can be applied by twisting between thumb and forefinger.
Dan


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## Jhawk (Dec 24, 2018)

I have seen a post (don’t remember where) about using brass tube the size of the inside diameter of the the threads. Glue diamond grit on the bottom of the tube, chuck up in your mill/drill press and grind the tap out. Supposedly you grind the threads off the tap, that’s why a tube is used. Haven’t tried it but think about experimenting with it ever now and then.


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## BP_1 (Dec 24, 2018)

Wouldn’t call this advise, but maybe a conversation starter...I have a 2-56 tap broken in an Al casting flange. My best remediation plan so far is to burn the broken tap out with an EDM. Thoughts?


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## colby15642 (Dec 24, 2018)

Buy an inexpensive "sliding machine-mount" tap wrench like this one for $16.00:  https://www.mcmaster.com/tap-wrenches   

McMaster-Carr part #2550A64

First drill should be a spotting or center drill for precise hole location in relation to spindle center-line.  Drill and tap with one set-up so that the drill-press or milling machine spindle remains perfectly aligned with the hole.  Use a new commercial-quality USA-made tap.  Save your Chi-Com and hardware-store-grade and well-used taps for cleaning threads in rusty manure spreader parts.


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## john_reese (Dec 24, 2018)

If using spiral point or spiral flute taps DO NOT reverse the tap every revolution.  It is not necessary or desirable to break the chips with these taps.


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## MachineTom (Dec 24, 2018)

Small broken taps are usually the most difficult to remove. If the is any material above the base workpiece this has worked for me. First photo shows a countersunk hole, which fits over the broken tap. Fill the hole with weld then unscrew the tap, as in photo two. Thats a 4-40 tap.


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## Ken I (Dec 25, 2018)

Broken taps in brass or aluminium can be removed by boiling in Alum (Aluminium Sulphate) - same stuff used as flocculant in swimming pools.

Slow simmer in a saturated solution does the trick - it disolves steel but not brass or aluminium. 3 hours - its slow but effective.


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## Richard Carlstedt (Dec 25, 2018)

for very small delicate taps like 1mm (.039") I tap upside down.
I'd post a picture but do not know how.
invert your work and bring the tap up from the bottom , having a normal T handle tap wrench works as gravity holds it straight down like a pendulum and the "feel" is excellent, you only feel the chip load, no wrench weight or trying to stay vertical is taken care of by gravity and the bonus is chips fall out of the hole.  Works really well

having tapped thousands of holes , and breaking a tap in a part with 50-60 hours in it is a most unpleasant thing. So I built a home made EDM unit designed by Ben Fleming 
see:
http://www.liming.org/edm/index.html
https://groups.yahoo.com/neo/groups/EDMHomeBuilders/info
https://www.homebuiltedmmachines.com/

I was the first guy to build Bens first design and did it for $100  but had a lot of junk on hand 
here is a picture of the inside of the "brain"and his book is written for dummy's like me 

https://groups.yahoo.com/neo/groups...&sortOrder=desc&photoFilter=ALL#zax/365981007

Rich


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## petertha (Dec 25, 2018)

Just do a search for 'broken tap' here on the forum & you will have lots of reading, including by yours truly.

For small tap sizes up to 6-32 or about M4 I made simple holders from drill rod (tool steel, but unhardened). I feel there are several advantages.  Inexpensive & simple to make. Nice close fit on more area of the tap shanks for improved alignment. The OD slides inside a corresponding mill/drill collet or (my go-to method) ever so slightly loosened drill chuck jaws. This gives you a very sensitive feel for tap progression & keep the tap axis in perfect alignment from start to finish. The 2 set screws are all you need resting on the tap flats to resist torque. The tommy bar gives you nice feel or you can remove it if you want to run in for a ways under power. They are nice & short so you don't have to open up a wide gap to accommodate a typical ratchet tap handle & centering do-dad that consumes 6" of headroom. Its kind of part specific but I feel the best time to do the tapping is immediately after pilot drilling the hole since you are never going to be any more concentric to the hole which is another reason for bad threads or broken taps. Good luck!


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## Naiveambition (Dec 25, 2018)

The Carbide drill in my pic is 2.5 mm so they are rather small.  I've used them a couple few times and have had no problem snapping.   They actually went thru rather easily.   I broke it down to the level surface then lightly applied pressure progressively.    Also worked on a countersink bit that broke the tip off on the work.  
I did do some research buying them,  and was worried about the flex and so forth, and I don't have great machines, but no problems yet.   I agree 080 is gonna be tough as I can barely see the threads anyways.     their is most likely better options and I am not a machinist by any sort, but this has worked well for me so far.


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## twombo (Dec 26, 2018)

‘I’m on the verge of drilling and tapping  the 50-some holes in my steam loco  cylinder blocks. All 10-32.  All are blind holes,  but plenty of depth is available. good info here for the task.  I am considering  a tapping head for my mini mill. The reverse switch was  plug and play.  I have had good service from the better line of taps from McMaster.  I like the TiN coated HSS best. 65% thread depth is fine for my needs. Sharp, fresh, HSS taps and carefulprocedure should carry me through.  F ortunately, these castings have been really nice and consistent.    As an aside, My machine shop instructor taught me that the body to clearance ratio of the 6-32 is the worst out there. 6-40  is much superior strength!!  Funny how I proved he as right before the lesson!  For a variety of reasons in confluence. A busted 10-32 tap set me back years.  The failed extraction created such an eyesore that I scrapped my frame bars!!! Yikes! We live,  and Yearn!!!


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## TRIPLE (Dec 26, 2018)

All fine tread I cut I do with a Machine tap that is turn round in a box of bees wax, the grooves are filled with wax and when you turn back the tap and break the chips the chips will held in to the wax so it cannot cause damage the tread, after tapping clean the grooves with a brass brush for the next tapping.
On this way of tapping I never have broken a tap in sizes from M1 , M1.2 M 1.5 M2 etc. And allways tapping by hand so you can feel the resistance an the moment the chip is breaking when you turn back the tap.


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## redhunter350 (Dec 26, 2018)

Almega, lots of good advice on here but here's my three penne'th use HSS ground thread taps, yes they are a higher price but worth the money -- they CUT ! one source I use is MSC and Lyndon taps, excellent value when on offer ! 
Lubricants for mild steel / black iron [CRS & HRS ??] use coconut grease mixed with brake cleaner - we used to use Carbon Tetrachloride now banned;  for aluminium use mentholated spirit [de=natured alcohol] everyone has their own favourite and there are lots of commercial concoctions available now, my lubes date from the 1960's. but always worked well.
I see your material is 1/8" thick so really it should cause you no problems providing you use good taps and I would use hand tapping so you have the 'feel" and to keep it plumb a tapping block to start the thread.


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## rodue (Dec 26, 2018)

I have found that in brass or aluminum that I use a piece of drill rod and turn it to  a little larger than you broken tap. Then drill a hole in drill rod large enough so the tap could turn inside. Then cut accouple of teeth on your drill rod. Then temper  the end, The broken tap will act like a pilot and bore it out ,you should go deep enough that you can snap off your broken tap. Then you can re tap the hole with a larger tap and  plug,  you can re drill  and  re tap, using more caution, I haven't tried it in steel   but this has worked for me


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## Roger Pry (Dec 27, 2018)

TRIPLE said:


> All fine tread I cut I do with a Machine tap that is turn round in a box of bees wax, the grooves are filled with wax and when you turn back the tap and break the chips the chips will held in to the wax so it cannot cause damage the tread, after tapping clean the grooves with a brass brush for the next tapping.
> On this way of tapping I never have broken a tap in sizes from M1 , M1.2 M 1.5 M2 etc. And allways tapping by hand so you can feel the resistance an the moment the chip is breaking when you turn back the tap.



Valuable info for me. RMP


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## goldstar31 (Dec 27, 2018)

I tend to use lard oil for general lubrication and usually add tallow mixed in for tapping.

It's old but in the home workshop it works well.

Regards

Norm


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## KMSK1 (Dec 27, 2018)

Tap Magic for aluminum Best I have found so far,,, Do have two back out tap and clean chips ,I tap a total of 8 holes in a .250 x .500 x .800  Alum block 6 are length ways through block 2 though the .250 . I use a drill buy hand , 3mm tap.


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## john_reese (Dec 28, 2018)

If using a T type tap wrench keep the chuck a bit loose.  When your hands wobble that little bit of slack can keep you from snapping a tap.

Instead of beeswax I use the wax stick intended for lubricating tools.  There are many brands available.  It is also a great lube for driving wood screws.


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## mfrick (Dec 28, 2018)

I have found that Goose grease works well with small taps it runs to the heat and not away like some cutting oils, just need to find a source. I have a friend who hunts and he gives me the fat and I render it down just for the purpose of taping holes.  I used lard  oil for yrs but get infections form it so industry went to the sulfur based cutting oils.  Now everything is getting to be a synthetic based material.
Mike


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## john_reese (Dec 28, 2018)

Use straight lard, Crisco, or bacon grease.  None of those will cause an infection if fresh.  Some use vegetable oil.  All seem easier to get than goose fat.   Actually, I have read that almost any animal fat or vegetable oil will work.


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## Roger Pry (Dec 29, 2018)

john_reese said:


> If using a T type tap wrench keep the chuck a bit loose.  When your hands wobble that little bit of slack can keep you from snapping a tap.
> 
> Instead of beeswax I use the wax stick intended for lubricating tools.  There are many brands available.  It is also a great lube for driving wood screws.




I want to learn how to drill and tap small holes for an undecided project so practice is what I want to do... so does anyone have an opinion on using an archimedes drill to help with my unsteady hands on a tricky bit of work? It would allow me to have two hands on the drill at the same time..


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## Cogsy (Dec 29, 2018)

You still have to hold the drill/tap straight so I don't see the advantage. Plus, for very small drills, you want very high RPM which you're not going to get by hand. Much better to have the work clamped so it can't move and utilise the chuck used to drill the hole to locate the tap in the same setup. Therefore everything stays in alignment and straight.


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## dazz (Dec 30, 2018)

Hi
I use a MT3 precision spring centre either in the drill or lathe tailstock.  The spring centre keeps the tap properly aligned.  Proper support and alignment significantly reduce the risk of snapping a tap.

I had plans published in Model Engineer magazine a while back.


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## tornitore45 (Dec 30, 2018)

> using an archimedes drill


Something I would never do.
If the alignment is supplied by a machine there is no problem.
If the part can not be tapped on a machine use a small diameter driver between thumb and forefinger.  The longer the driver the less wobble.
I am sure that all the good techniques for tapping small holes have been found and described, there is no need to re-invent a wheel and make it square.
After unavoidably breaking a 1/2 dozen taps and successfully tapping 100 holes you get the hang of it an never break one tap again.  Breaking taps is the price of learning, since is not something one can learn from a book.  However learning from others, books or otherwise is helpful.


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## petertha (Dec 30, 2018)

dazz said:


> I use a MT3 precision spring centre either in the drill or lathe tailstock.  The spring centre keeps the tap properly aligned. .



The only issue there is, many of the small taps we are talking about don't have a female centering dimple for the classic spring male center. The taps are typically a semi ground cone & not necessarily a consistent cone angle across manufacturers. So some folks propose another fix - a conical cup held in the spring center. But that is right adjacent to the squared lands where the wrench jaws go. Personally, I don't find the requirement for down force is an issue on fine, finicky threads. You can feel the first couple threads & then it smooth sailing. Consistent alignment with minimal axial variation is the goal IMO. Larger threads, for sure the spring center is very useful. I guess we all have our way of doing things.

For fine threading aluminum, I find these style of taps do a good job. (Its just an internet picture, not necessary a brand endorsement). The flute angle and the reduced shank helps vacate chips over the classic taps. Blind holes should utilize chip ejecting style taps.


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## dazz (Dec 30, 2018)

petertha said:


> The only issue there is, many of the small taps we are talking about don't have a female centering dimple for the classic spring male center.


I hold the tap in a T tap wrench.  That has a dimple that fits my spring centre.


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## john_reese (Dec 30, 2018)

For small taps with a male center on the top I grip the middle of the tap with my small Starrett tap wrench.  The top of the tap is guided by the female end of spring center.


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## Roger Pry (Dec 30, 2018)

petertha said:


> The only issue there is, many of the small taps we are talking about don't have a female centering dimple for the classic spring male center. The taps are typically a semi ground cone & not necessarily a consistent cone angle across manufacturers. So some folks propose another fix - a conical cup held in the spring center. But that is right adjacent to the squared lands where the wrench jaws go. Personally, I don't find the requirement for down force is an issue on fine, finicky threads. You can feel the first couple threads & then it smooth sailing. Consistent alignment with minimal axial variation is the goal IMO. Larger threads, for sure the spring center is very useful. I guess we all have our way of doing things.
> 
> For fine threading aluminum, I find these style of taps do a good job. (Its just an internet picture, not necessary a brand endorsement). The flute angle and the reduced shank helps vacate chips over the classic taps. Blind holes should utilize chip ejecting style taps.



Is the idea behind the spiral ground (ccw) tap that the chips are worked back up and out of the hole with each reversal of the tap during the tapping action?


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## john_reese (Dec 31, 2018)

On spiral flute and spiral point taps reversing the tap periodically is not desirable.  Spiral flute taps draw the chips out of the hole as long strings.  Spiral pointed taps push the ships ahead of the tap as long strings.  Just feed those types of taps continuously.  If you reverse the tap to break chips the shorter chips may not evacuate properly.

Even with conventional hand taps it is not always necessary to reverse the tap to break chips.  I recently tapped 24 1/4-20 holes in cast iron about 3/4" deep using a tapping head.  That gave constant rotation until I hit final depth and then reversed and backed out the tap at double the spindle speed.


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## petertha (Dec 31, 2018)

Roger Pry said:


> Is the idea behind the spiral ground (ccw) tap that the chips are worked back up and out of the hole with each reversal of the tap during the tapping action?



My post #38, right hand picture shows the chip ejecting style of tap in action. These taps are preferred in blind holes so chips don't go down into the hole cellar, bung up the tap & risk breakage. I've also heard you are not supposed to reverse these to break the chip like conventional taps & that makes sense. Blind holes shouldn't be substantially deep anyway. What I have done just to be safe on certain holes is wound the tap out completely, give it an air blow & then proceed in again. Personally I find the good quality taps of this style to work excellent. When you have a through hole, forward ejecting taps have an exit for chips to drop out. Or at least theoretically that's how its supposed to work.LOL


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## Wizard69 (Dec 31, 2018)

almega said:


> Since the material I need to tap is only 1/8" thick and will be through tapped, what about using self tapping screws to create the threads?  Those are much less costly than the taps and though they might only be good for one or two threads, they might be more cost effective in this case.  Thoughts?


Self tapping screws in my opinion are only good for holding sheet metal on a barn.  I would not use them to many fine model or even a machine tool.   

This is prett much repeating what has already been said but here are my suggestions. 

1. Buy quality HSS taps.  If not HSS the new super composite materials might work.  For small threads we two flute taps.  Never buy or use plain carbon steel taps as they seemingly are bottom of the barrel quality no matter who makes them.  

2. Always use plenty of lube suitable for the material being tapped. 

3.  As others have noted tap alignment is critical.  Most people need a tapping aid.  However a taper tap can be helpful in unaided tapping. 

4.   Contrary to many posts here do not use a drill press chuck for tapping of the extremely small tap sizes.  It works fine for larger sizes but there is too much inertia in most drill presses for this to work well for small taps. The cut off for me and my drill presses is about 8-32, anything smaller is a problem.   However a tap follower in a drill press guiding a tap handle is a good idea.  

5.   Speaking of tap handles, most are way too big thus not allowing the feel you need.  In many cases what you really need is a knob on the tap of one inch or less in diameter.   Such a knob is a good lathe project!   Make sure it is equipped to allow a tap follower.  

6.   I’m not a big fan of drilling over sized holes for the taps.  There is some leeway but I really don’t like going to far below 70% thus would tend to stop at 60%.   Shave too much cut off and you can have issues with fasteners that may be at the lower limit.  This especially with finer threads.  

7.  By enlarge the majority of tapsive broken over the years are a direct result of being in a rush or trying to get more threads than the tap or hole allows.   The real trick is to be able to stop yourself when you mind isn’t right for tapping.  If dinner is on the table, go to dinner and leave that last hole for another day.  Often it is the guy in the mirror and not the tap that is the problem.  

8.   You mentioned Vermont American.  I can’t speak to all of their products but the majority of the big box hardware store offerings are crap.  Actually anything the big box store carry seems to be crap.  Recently though some of the local stores seem to be putting in the effort to upgrade cutting tools with higher quality tools.  For the most part though  shopping at the big box hardware stores for taps and dies is a waste of money and time.  

9.  If you are in a situation where a tap follower can’t be used consider tapping blocks.  They can be wonderful as a tapping aid.   Building a tapping stand is an alternative but it isn’t mandatory.  From my perspective the real reason to build a tapping stand is to make it a platform for multiple uses.   Otherwise tapping aids can be extremely simple, as simple as a V groove milled  in a block of material.   That material can be a piece of hardwood in a pinch.  The goal is to support the tap square to the bore.  The blocks with the V groove have a huge advantage in that you can see what you are doing, tapping blocks cover up the working end of the tap.  

10.   Instead of using the chuck of a drill press or mill for that matter, consider using it as a tap guide.  Adjust the jaws so that the tap shank just slips.  Then use you fingers to spin the tap in started square.   Very small taps will start with a finger grip on the shank while larger ones will require something to grip the shaft.  This is a good place for those tapping knobs described above.  

Best of luck.


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## DJP (Dec 31, 2018)

petertha said:


> My post #38, right hand picture shows the chip ejecting style of tap in action. These taps are preferred in blind holes so chips don't go down into the hole cellar, bung up the tap & risk breakage. I've also heard you are not supposed to reverse these to break the chip like conventional taps & that makes sense. Blind holes shouldn't be substantially deep anyway. What I have done just to be safe on certain holes is wound the tap out completely*, give it an air blow *& then proceed in again. Personally I find the good quality taps of this style to work excellent. When you have a through hole, forward ejecting taps have an exit for chips to drop out. Or at least theoretically that's how its supposed to work.LOL



I have compressed air in my shop to support the other side which is dedicated to auto repair. I use the air to run power tools and the dry off  Varsol soaked parts for cleaning, however I have an aversion to using compressed air to clean chips off my machines or tools. This may be off topic but I have to mention the danger to your eyes when tiny metal chips fly in unexpected directions.


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## john_reese (Dec 31, 2018)

DJP said:


> I have compressed air in my shop to support the other side which is dedicated to auto repair. I use the air to run power tools and the dry off  Varsol soaked parts for cleaning, however I have an aversion to using compressed air to clean chips off my machines or tools. This may be off topic but I have to mention the danger to your eyes when tiny metal chips fly in unexpected directions.


That is why I keep a big Shop Vac around.


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## petertha (Dec 31, 2018)

Point taken. Nobody said anything about blasting chips & tools with air. I don't agree with that either. You have a regulator. Set it on very low.  Mine is probably less than an aerosol can electronics cleaner. I position the nozzle over the hole & put a rag over the work. The chips go into the rag, not into the air. Safety first boys & girls.


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## john_reese (Dec 31, 2018)

I admit to using air occasionally to clear chips from small holes.  About the same procedure you follow, Peter


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## RonW (Jan 1, 2019)

Happy New Year to all. I am surprised that through all of this no one has mentioned using a first, second and bottoming tap in sequence with small taps. I regularly use #4 and #6 taps in aluminum, (sorry about the American spelling) and seldom have a problem. I buy good HSS taps from Spaenaur in Kitchener, Ontario and they have seldom let me down. For the most part a second cut tap will fit the bill if cost is a factor but for blind holes the full set works best. For cutting lube I use tallow for steel and a tapping fluid for aluminum. Brass is done dry. Ron


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## Dubi (Jan 2, 2019)

RonW said:


> Happy New Year to all. I am surprised that through all of this no one has mentioned using a first, second and bottoming tap in sequence with small taps. I regularly use #4 and #6 taps in aluminum, (sorry about the American spelling) and seldom have a problem. I buy good HSS taps from Spaenaur in Kitchener, Ontario and they have seldom let me down. For the most part a second cut tap will fit the bill if cost is a factor but for blind holes the full set works best. For cutting lube I use tallow for steel and a tapping fluid for aluminum. Brass is done dry. Ron



Happy New Year. Interesting post. In our shop we will use Tapmatic (both types) and will tap Brass dry as you stated. However, in one case we had some very expensive special underwater switches which had 5/16 whit bushings but they would not fit into the machined housings.

We made a special jig to run a die down the threads, they stuck and twisted so I ordered that the technician put a drop of paraffin on the bushing. The die ran down beautifully. I still do not know why the die stuck as it did.


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## olympic (Jan 2, 2019)

While reading this thread I just realized that "small taps" seems to mean #4 or #6 to many people here. However, there are much smaller taps in use (#2,#0, etc.). Does anyone have advice on removing broken very small taps? 

I seem to use 2-56 and 0-80 a lot, but I have never broken one, not even in that nasty aluminum; that being said, I think that it's just a matter of time....

Oh. I did break a 000-120 tap once, but that's because I knocked the delicate (and expensive) little thing off the bench onto the floor. Ouch!


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## Gene Pizzoli (Jan 2, 2019)

olympic said:


> While reading this thread I just realized that "small taps" seems to mean #4 or #6 to many people here. However, there are much smaller taps in use (#2,#0, etc.). Does anyone have advice on removing broken very small taps?
> 
> I seem to use 2-56 and 0-80 a lot, but I have never broken one, not even in that nasty aluminum; that being said, I think that it's just a matter of time....
> 
> Oh. I did break a 000-120 tap once, but that's because I knocked the delicate (and expensive) little thing off the bench onto the floor. Ouch!


If you haven't broken a small tap yet you're  in for a humbling experience. Most taps are broken due to misalignment or failure to relieve the chips by backing off. You can counter this to some extent by a drilling a small pilot hole in a piece of scrap equal to  the diameter of the tap body. Other wise, In my experience, use a hollow mill and replace it with a bushing.  However if you believe in miracles you can pray a lot. Regards, Gene


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## Roger Pry (Jan 3, 2019)

Thanks Olympic and Pizzoli these examples are the sizes I'm looking at.... I intend to try to build some test pieces on the order of a large pocket watch. Some holes will be in positions where setting up in a machine(mill etc) is not my intent. This testing is for skill honing. earlier I mentioned the Archimedes drill( I purchased a micro version on ebay) because I wanted to experiment an need alignment, down force and twisting action all at the same time. I've worked using 4-40 to 2 1/4" screws/bolts in industrial situations and now in retirement want to go smaller instead of bigger.


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## rad1945 (Jan 4, 2019)

With 55 years as a practicing Mechanical Engineer; using taps of all forms and sizes from 0.5o mm  up to 150mm diameter. I have found the best solution has always been Goliath Threading products in conjunction with "Tap Magic" fluid.
Both of these products seem to be available just about everywhere.
If they are not available in your local store, they are through Amazon.

To remove a broken tap I normally go for a spark eroder.
Another item freely available from Amazon.  The swearing you will provide trying to get out that first tap by the means will surely be paid from the life long service you will get from that eroder of your life time.


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## neilw20 (Jan 4, 2019)

Use taper, intermediate then plug tap.
I just use the intermediate, and then plug tap for blind holes.
I resharpen the intermediate as a gun tap, or just buy one. They are often called spiral point.
Reduces cutting load considerably. Tiny diamond disk on dremmel is easy to do the gun relief. (at least for me).
Disadvantage.. Chip goes ahead of tap, making blind holes a bit of a fiddle clearing spiral swarf.
https://www.ktstooling.com/images/F...d_Pic/5301TC_PHO_4C/5301TC_PHO_4C_Enlarge.jpg

ALWAYS use Tap magic or similar. Not just ordinary oil. The high sulfur stuff the plumbers use on their big pipe dies is ideal.
NEVER do it dry.  Reverse often. Candlewax quite often ok on alumin(i)um
I often do down to 1 mm. Bit fiddly to sharpen... haha.
I set part in vice.
Drill correct size hole. Next size up for steel, often.
I have a pin I put in the drill chuck, with a rubber grommet on it.
Pin fits nicely into end of tap wrench.
With the rubber grommet drive, as soon as the tap goes in a bit, the pressure on rubber gets less, and then less torque.
Reversing out is not as forgiving.
It is VERY important to stay concentric and NO BENDING loads off line.
Last time I broke a tap, was when I dropped it on the concrete.


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## hula-hula_guy (Jan 5, 2019)

My experiences with tapping aluminum ( and all non ferrous materials  ) and I have 25+ years - use WD-40, it's a light runny solution that will follow the tap down the hole - not scrap off at the hole opening and lubricate only the exposed part of the tap like heavy tap oils. For all ferrous materials I like using tapping wax sticks, they melt at very low temps so the stuck wax to the tap will start to flow lower in the tapped hole as the tapping process starts to generate a small amount of heat. 

As other have stated and probably the most important thing to take away from here is buy a good tap from a good industrial supplier. I have a good supplier who recently I needed to buy a 0-80 spiral point 2 flute tap for $7.00 bucks. And to compare I can get a very common 3/8-16 tap in a hard grade ( for tapping A2, D2, M2 tool steels ) for $12.00. I do have my own machine shop and we do get shop prices, so anticipate these quoted prices to be about 20% more, still very obtainable prices. Talk the the guys at the industrial supplier, tell them what you are doing and your experience level, they have resources far beyond what any of us truly know to help you out. 

A good tap for the correct application should last 800-1000 holes easily,  I have seen it with my own eyes. Ask for an old catalog,  read through it and learn what tools are available to you  - for instance, you will learn several companies taps are colour coding their taps - blue line for cast iron,  yellow line for general purpose,  green line for non ferrous,  red line for stainless,  black line for hardened materials. Prices between all those grades vary less than 10%. So buying for the correct application is not that expensive. 

Above all, practice, take your time tapping,  and truly focus when tapping - feel, sight, sound - these are all the factors for a successful tapped hole. As another person stated using your mill or drill press to start the tap, helps you get the feel for things and get a nice true straight start on your tap, then finish by hand will a good quality T handle for small taps say up to 3/8, and a regular tap handle for larger sizes. 

HAPPY TAPPING!


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