# What Is The Smallest Tap You Have Used?



## rake60 (Mar 18, 2009)

I like the little stuff.
That brought a question to mind.
What is the smallest hole you have ever tapped?
Personally, I have never tapped a hole smaller than 2-56.
I own smaller taps like this 1MM.





It has never been used.
Reasons would include, I don't own a chuck that will hold a drill bit that small
nor do I own a machine with a spindle run out that wouldn't break that drill bit.

So back to my original question.
What was the smallest hole you have ever tapped?

Rick


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## Hexbasher (Mar 19, 2009)

i setup my okuma at work for M1 tapping once...lol


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## stefang (Mar 19, 2009)

Some time ago i had to tap two 1mm threads in silversteel...real fun 

Did it free hand, workpiece and tap with holder in hand, trying to stay square...

Stefan


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## spuddevans (Mar 19, 2009)

I'm still a newbie at model engineering, the smallest I've drilled and tapped is M2.5.


Tim


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## tel (Mar 19, 2009)

I've done a few 1mm and heaps of 12BA (1.3mm) Freehand is by far the best way to go with those little 'uns


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## BMyers (Mar 19, 2009)

0-80 just a bit stressful


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## joeby (Mar 19, 2009)

I have some 00-90 taps that are unused, haven't had the need to go that small yet. The smallest that I have used were 1-72.

 I had a job interview last week, the company makes parts from 6061 aluminum and some have hundreds of tapped holes down to 0-80. They are all form tapped and I remember them saying that they tap 2-56 at 2000 rpm. Sounds fun!

Kevin


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## gbritnell (Mar 19, 2009)

I have used a 1mm tap and die quite a bit. Whenever I tap with it I use a small pin vise to hold it. In using a pin vise all the torque that you apply is close to the centerline of the tap so it reduces the chances of breakage, that's certainly not to say that I haven't broken one. Here are a couple of pictures of my smallest engines that have quite a few 1mm tapped holes and nuts and bolts. In the picture of the small vertical engine I have included a tire valve cap as a size reference. In the beam pictures I have set and American dime next to the engine.
gbritnell


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## 90LX_Notch (Mar 19, 2009)

I just did 1-72 the other night.


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## Philjoe5 (Mar 19, 2009)

gbritnell
Did you make those hex head screws? Small ones are not so available it seems.

Cheers,
Phil


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## mklotz (Mar 19, 2009)

The smallest I've ever tapped for an actual project was 00-90 (0.047" = 1.19 mm diameter).

A friend bet me that I couldn't tap a hole into the end of a 1/16" brass rod. Using a Unimat, I drilled and tapped it axially for a 000-120 (0.034" = 0.86 mm diameter) and then cross-drilled it and tapped that the same. I mailed him the product and won the bet. Sadly, he never sent it back and I'm not going to try to make another one.


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## cfellows (Mar 19, 2009)

gbritnell

Beautiful work! Love those small engines.

Chuck


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## rake60 (Mar 19, 2009)

Now I really need to attempt that 1MM.

Amazing work gbritnell!

Rick


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## Cedge (Mar 19, 2009)

0-80 has been my smallest tapped thread. I commonly tap 2-56 threads by hand, after doing many 100's of them. 

Gorgeous Engine!!!!!!!!!

Steve


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## ghart3 (Mar 19, 2009)

Needed a 0-80 left hand tap for turn buckle and thought they wanted too much money for a one time use tap. So made one.


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## GailInNM (Mar 19, 2009)

Back in the days when I was a young man (under 60) I liked to do small stuff. Attached photo is of shop made 1 x .25 mm form tap and a couple of 0.5 x 0.125 mm hex head screws. I made form taps for them also, but can't find them at the moment. The big bolt in the photo is a 0-80 x 1/4.
The hex head screws were single pointed from 1/8 inch bar stock brass 360 and the hex heads were formed with a shop made rotary broach before cutting off. The hex heads are 0.034 inch across the flats. 

I still use 0-80 on a routine basis and do 00-90 as required but avoid the small stuff. Various magnification aids are required any more. The front and rear crankcase covers in my current threads on the PMC IMP are each held on with 0-80 fasteners. The largest threads in the engine in my avitar are 0-80.


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## ChooChooMike (Mar 19, 2009)

:bow: to all youse gutsy guys !!!

George - any more pix to share on those great looking engines ? Maybe start another thread just for those small wonders !!

Mike


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## fdew (Mar 19, 2009)

There was a story years ago about a couple of shops bragging about who could make the smallest bolt.
The British shop made a very small bolt and nut, and sent it to the US shop.
the US shop cross drilled it put a bolt through it and a nut on the new bolt.

A old German guy in the US shop saw it waiting to go back and drilled and safety wired the new nut.

Feel free to change the countries if retold.

Frank


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## old-biker-uk (Mar 19, 2009)

Smallest I have done is 16BA (about .075mm OD)




Full details of the model lathe here.

Mark


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## Lew Hartswick (Mar 19, 2009)

Ive done quite a few 1-72 and some 0-80s. Lots of 2-56, 3-48 etc.
  ...lew...


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## stevehuckss396 (Mar 19, 2009)

000-120 is the thread that holds the cylinder on the Micro HOSC. I do 0-80 and 2-56 mostly.


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## Loose nut (Mar 19, 2009)

1-80 in stainless steel.


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## gbritnell (Mar 19, 2009)

Hi Phil,
Yes, I made the hex heads on the nuts and bolts. I first turn the shank of the bolt. If it's long I do sections at a time. With the shank threaded I turn the head diameter leaving about .010 extra. I then take it out of the lathe and put it in my small dividing head and put the hex on it. After that I saw the bolt off with a jeweler's saw. I have tried parting them off with a .020 cutoff tool but have lost too many to the chip pile thus the saw. I then thread them into a little arbor on the lathe and turn the head to length and polish it. It sounds like alot of work but it's not really. I usually do a dozen or so at a time. Bye the way I do part the nuts off. I put a piece of piano wire in my tailstock and insert it into the threaded hole then use my .020 cutoff tool to part them off. I then put them into an Allen set screw of the correct size and file the little burr that's left on them. 
gbritnell


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## Philjoe5 (Mar 19, 2009)

Thanks for the description gbritnell. I've made some 10-32 bolts that were 2" long pretty much as you've described, but I really haven't done the small stuff to any extent. I'm fascinated by those who can work in that scale.

Cheers,
Phil


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## Maryak (Mar 21, 2009)

6BA and I don't enjoy it one little bit. 

Best Regards
Bob


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## steamer (Mar 26, 2009)

00-90...my hands are too big to tap anything smaller....not without a tapping stand anyway


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