# 2 mm tapping



## Herbiev (Oct 2, 2012)

Hi all. Just after some advice on tapping 2mm threads. The Dubro tap came with a 1.56mm drill and I used Treflex tapping grease/compound but they keep breaking when tapping steel. Should I use a larger drill or different cutting fluid?  Is there any such thing as a 2mm carbide tap?  Any tips or advice greatly appreciated as at $10.00 a go it is getting expensive.


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## ttrikalin (Oct 2, 2012)

Mayhaps the tapping technique can be improved.

How do you guarantee that the tap is following the axis of the hole exactly? E.g., for a hole perpendicular to a flat surface, do you use a tapping block?

Take care 

Tom in MA


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## rake60 (Oct 2, 2012)

It would depend on the application.

Many tap drill charts are for a 75% thread.
You really rarely need that in model scale.

If the fastener is holding high pressure, a 50% thread in steel is required.
If there is little pressure on the fastener you can get away with a 30% thread.

I always use a drill bit one size larger than recommended but that's just me.

Rick


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## ruzzie (Oct 2, 2012)

For metric tapping size the easiest way to get the tapping size is to subtract the pitch from the diameter 
M2 x.4 = 1.6 tapping drill, I use 1.65 - 1.7 for harder materials
Cheers
Paul


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## gbritnell (Oct 2, 2012)

Paul is correct about the drill size for that particular tap. I am currently working on some very tiny steam engines and all the holes are 1.0x.25 mm threads. I am tapping mild steel (12L14) but have found that I had to go up .002 from the calculated drill size because the tap was turning very hard. I don't know what the Dubro taps are made of but I suspect they are carbon steel as opposed to high speed steel. All my taps are high speed steel. 2mm is .078 diameter so it shouldn't pose a big problem as I tap 0-80 (.06 dia.) all the time. Another suggestion is to use a small chuck to hold the tap as opposed to a tap wrench. With a tap wrench you have too much leverage with the handles. By using a small chuck you get a better feel for what the tap is doing. 
Attached are a couple of pictures of the small steam engine I am building and the tapped holes I'm referring to. 
gbritnell


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## lensman57 (Oct 3, 2012)

HI,

I use these taps made by Europa Tools, they are the best I have ever used and no material is too tough for them. Use 1.6mm drill for 2mm tap and any cutting tapping fluid will work with these. Do not be heavy handed with small bore tapping please.

http://www.ebay.co.uk/itm/M2-X-0-4-...Home_Garden_PowerTools_SM&hash=item3f13791e53 


Regards,

A.G


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## Ken I (Oct 3, 2012)

I've done a lot of M2 holes and use 1.5 or 1.6 for aluminium, 1.7 for steel and even 1.8 for horrible stuff.

Must use a tap guide. Normally they break because of side (bending) loads.

This is what I use - a free floating pin chuck - holds centre and finger power only.

Ken


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## Henry (Oct 3, 2012)

When I have need to cut any kind of metal I love to put a little of salicylate methyl, It helps a lot.
http://en.wikipedia.org/wiki/Methyl_salicylate


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## Herbiev (Oct 3, 2012)

Thanx to everyone. A lot of good info there so I feel far more confident now.


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## bazmak (Jan 12, 2013)

Hi Herby of hallett cove, i never use tapping grease ,it holds the swarfe.I always use WD40 its slightly abrasive.
For tapping small holes ie 3mm or smaller i always use a tapping chuck not a T handle, hand held and hold the workpiece in your hand
not in a vice.Its all a matter of touch you can feel any resistance,and clear out the swarf. every 14 turn you can check on perpendicular. Be patient slow is quicker than break
Barry (seacliff) Did you do any work in the 45o C the other day


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## Herbiev (Jan 12, 2013)

Hi Barry. Thanks for the tips. The only work I did in the 45 degree heat was to open the refrigerator door and pull the ring off a tinnie or six.


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## goldstar31 (Jan 12, 2013)

I think that there are 2 issues here. Both were addressed by George Thomas but seem to be studiously ignored- and ignored. GHT wrote about this in Model Engineer way way in the past but his writings were published in book form by my friend Dr W A Bennett.  Bill took on the task( and it was) at the request of George's friends and associates.
A few coins come his way in 'royalties' but I suspect they are of really little import.

Rant over? Well, what did he say? He described his professional experiences of broken taps in the - what it 3 engineering firms- that he owned. It certainly wasn't a 'one off situation' GHT made up a 'Universal Pillar Tool' and it became known as this because another guy - built model steam locos. The name was L.C. Mason. Heard of him?
Me? Well, I'm just an old, old amateur but I have made a pair of these UPT's over the years. The first when I could afford the castings and welded bits together. So the castings are still available- and so are the books.

No, the gripe isn't quite over because I wrote fairly recently- a month or so ago about making one from what was the con rods of a scrap Mini  or BMC 1000 A series.

Back to my coffee- I'm too deaf to hear the crack of taps.

Norman


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## Shawn (Jan 12, 2013)

You could build or buy a hand tapping machine. I built one, it seems to work quite well, better as taps getting smaller.











Shawn


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## Chriske (Jan 12, 2013)

Most important while tapping small holes is hand holding the workpiece. I never use T-bars on the tap-holder. I always use cutting fluid.

After reading this topic I will try and use WD40. Just maybe it will cut even smoother.
Never to old to learn...


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## Woodster (Jan 12, 2013)

You could always try a Roltap or Fluteless Tap instead of a standard cutting tap. These tap are great on small diameter as they don't have flutes so are inherently stronger. You will have to drill a bigger hole, but you will get a stronger thread and are less likely to break the tap. Because there is no swarf produced, you can also get deeper into the hole. Not cheap though!!!! But should last a damn site longer!!


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## e.picler (Jan 12, 2013)

Hello guys!
I`m also tapping several 2mm holes on my project and I aways get scared to break the tap (here in Brasil they are very expensive). What I found to be very effective, is to usi the collet to hold a pin of abount 2 - 2.5mm and guide the pap wrench as you can see on the picturo bellow. Another good care is not turn more than 1/4 of a turn than tur back to break the ship/swarf otherwise it will jam the tap and cause the break.






Hei Ken I liked your idea of the small chuck with free movement. I will do tha for me too I think it will work great.

Cheers,
Edi


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## gus (Jan 12, 2013)

Here's how I do it,with job piece held in tool makers vice and tap held by drill chuck,hand lever feed tap to hole and turn by hand with no reverse.Turning my hand gives good feeling.If too much force is required ,you have a problem.Drill hole too small.
I use Japanese machine taps for their high quaiity and sharpness.For blind hole I use spiral taps that brings chips out of tap hole and straight tap with chips down to hole for through holes.For 2mm x 0.4. A tap drill of 1.6mm is required. I use Tapamatic Tapping Oil.
Tapping with tap wrench is very risky with 2mm tap. Manual tap is not user friendly. Machine tap best. HSS tap best.
Foto shows a 2mm tap about to be downgraded to tap aluminium or brass.I paid S$8.50 fot 2mm tap.


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## goldstar31 (Jan 12, 2013)

As a sort of followup, there is a problem which starts the possible breakage and that is a blunt or damaged tap. One lot of trouble is the fact that the tap is damaged by being used 'out of the vertical' and this breaks one side of  an already thin tap. The next time the tap is used, it has to cut a thread with TWO flutes that are moderately sharp and one which isn't. The overload- and the possible misalignment- breaks the already damaged tap.I prattle on about tool and cutter grinders- but no one reads the blurb and the number who make a tool and cutter grinder.  Taps and dies do not last for ever- but can be ground- but only with some simple device.

Time for more coffee

Norman


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## gus (Jan 13, 2013)

goldstar31 said:


> As a sort of followup, there is a problem which starts the possible breakage and that is a blunt or damaged tap. One lot of trouble is the fact that the tap is damaged by being used 'out of the vertical' and this breaks one side of  an already thin tap. The next time the tap is used, it has to cut a thread with TWO flutes that are moderately sharp and one which isn't. The overload- and the possible misalignment- breaks the already damaged tap.I prattle on about tool and cutter grinders- but no one reads the blurb and the number who make a tool and cutter grinder.  Taps and dies do not last for ever- but can be ground- but only with some simple device.
> 
> Time for more coffee
> 
> Norman




Hi Norman,
You are right.  All Taps must be given a go over eyeball check before commencing tapping. Out of vertical is another cause.Blunt taps too.Too big a tap wrench is another cause.Have seen a steel casting with a 1/2 " BSF tap snapped inside a deep hole.They blamed the poor apprentice for the disaster. After a week's futile effort,they decided to make a new piece. Week later we were issued new taps--------"Triangle" Taps and no more recycled taps. The boss gave in.


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## goldstar31 (Jan 15, 2013)

Gus, 

Unfortunately there is a lobby here which cannot relate that one cutting tool is much the same as another and behaves in much the same way. there is a lobby that is prattling on- seemingly forever about boring tools and here we have a lobby about boring tools which don't bore cleanly but bore with a thread. Other people make a sort of effort to clean up a boring tool- which left to its own state- will tap a sort of thread.

They are ALL mixed up. I'll go for more coffee-- and something for a headache-- which they are causing.

I CAN grind taps-- they can't.They have problems which I don't.

More coffee? 

Norman


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## MuellerNick (Jan 15, 2013)

Why not make it right from the start but use "tricks" that don't work?

The right bore for M2 is 1.6 mm. Not more and not less. If the tap breaks, that happens because it is dull and not because you didn't bore oversize.
So, use sharp taps.
Use a tapping oil. WD40 is NO tapping oil, it is just crap that is sold overpriced.
Clamp the work in a vise. If you hold it in your hand, you have two moving targets and more difficulties to get the tap straight in.
For small taps, I use a handle like this one:




You just turn it with two/three fingers, very sensible. I bet you can build your own (and waste one weekend to save $5).

Use the right tap! A gun tap for through holes, a spiral fluted for blind holes (I almost only use spiral fluted ones).
Do not break chips every 1/4 turn. That's nonsense, the chips don't get out if they are broken in small pieces. They do get out if the tap cuts one single swirl.
You only break the chip if you feel that the resistance increases. Then turn the tap back out.

I don't remember when I broke my last tap. It must be several years ago.


Nick


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## Herbiev (Jan 15, 2013)

Thanks Nick but I will stick with experienced majority


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## goldstar31 (Jan 15, 2013)

Actually I built a GH Thomas Universal Pillar Tool( twice) which solves virtually all the problems of tapping/staking/rivetting and whatever. It can't be made in a weekend but a cheap drill ex Aldi , Hofer or Lidl may not be everything which you would desire but at about £30 or so can be a very handy tapping tool- as well as for the task for which it was designed. When the offers come on, you get a vise/vice as well. Not wonderful but way beyond fiddling and snapping and writing to here to say-- 'Please *********?'

I was in my local one( it matters not which one) but there was a tile cutter which would have made a beautiful grinder. There was an arc welding set and a battery drill that could have powered a a mill traverse or lathe. The costs of each were less than half a fill of petrol/gas/diesel in a small car.

The only possible snag was that people fail to recognise how cheap tooling can be modified.
That is not MY problem.


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## gus (Jan 15, 2013)

ruzzie said:


> For metric tapping size the easiest way to get the tapping size is to subtract the pitch from the diameter
> M2 x.4 = 1.6 tapping drill, I use 1.65 - 1.7 for harder materials
> Cheers
> Paul



Hi Pau

Thanks for sharing. Did not realise it was so simple to get tap drill size.

I bought a 150mm S.S.Steel rule fron TokyuHands,Japan and it had tapping drill sizes. Tend to misplace ruler and spent days looking for it for tap drill sizes.


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## MuellerNick (Jan 15, 2013)

> Thanks Nick but I will stick with experienced majority



So you wanted to say that I'm inexperienced because I don't do it like hobbyists?
That makes me lough!

I'm not saying anything against the universal pillar tool. It is great, build one! I'll make one too, I have access to the patterns for one.


Nick


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## goldstar31 (Jan 15, 2013)

If it is the GHT one, make certain that the arms are the Mark2 ones

Cheers
Norman


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## Herbiev (Jan 15, 2013)

We are all hobbyists and all have different approaches to these problems. As I am using good quality, brand new HSS taps I can now see that the main problem is not tapping on the vertical. Hence my next project will be a ght tapping guide   Thanks again for the input.


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## gus (Jan 15, 2013)

Hi Guys,
Here is how I do it with a S$120 Cheapo China Drill Press(which I have retrofited to be world best.Haha) and a tool maker's vice
also from China(but this vise is cheap n good).Have machine tap clamped tight in drill chuck,bring down tap to hole.Apply ample dobs of Tapmatic Oil(for mild steel).Next ,grab hold by hand and turn all the way to finish. During the tapping process do not oscillate tap especially spiral taps.
Steel been known as tap breaker and not very forgiving.3mm taps if not treated right will also break.So far no broken taps with 2----2.5----3mm. No experience with 1.5mm. Taps must be in tip top condition. My machine taps are Japanese made.No China Taps.See fotos.Would love to make a pillar tapping machine but my balcony workshop has limited space.


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## gus (Jan 16, 2013)

goldstar31 said:


> Gus,
> 
> Unfortunately there is a lobby here which cannot relate that one cutting tool is much the same as another and behaves in much the same way. there is a lobby that is prattling on- seemingly forever about boring tools and here we have a lobby about boring tools which don't bore cleanly but bore with a thread. Other people make a sort of effort to clean up a boring tool- which left to its own state- will tap a sort of thread.
> 
> ...



Hi Norman,
I have no broken taps. I buy only good Japanese Taps.No Chinese Taps or recycled taps.Your get recycled problems. 
Digressing. Are you a coffee nut? Gus is the official coffee boy.Coffee powder is ground when coffee is about to be made.Don't believe in Expresso Coffee Machine.Waste of money.Good coffee making is an art.Starting from the bean selection,blend and roast. See foto.


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