Taps

[lugnut]

Yesterday I broke a couple of my small taps (no I don't have a tap guide and Yes I can and have broken more than one tap ) SO This morning I'm in the process of ordering some new taps. But which ones do I wand and/or need?
My old friend Google lead me to a web page that has some very good information on different styles of taps and their use. I thought you all might find some use for the page also. I have no affiliation with the company, I just like their info.
http://www.newmantools.com/taps/styles.htm#tpb
enjoy
Mel

 

[rake60]

When I can find them, I prefer Spiral Point Taps.
As the link you indicated already says, they are stronger and cut
more freely than a Hand Tap, but I can only find them occasionally.

The rest are all Plug Hand Taps. Only because that's all I can find.
Has anyone ever seen a Bottom Tap in the miniature screw thread
sizes?

Rick

 

[lugnut]

Rick, ENCO has HSS spiral point Bottoming style taps Here:
http://www.use-enco.com/CGI/INPDFF?PMPAGE=49&PMITEM=890-9100
Maybe those are ones I should order :?:
Mel

 

[rake60]

I'm sure others would have a very different opinion, but the Spiral
Point works better for me than anything else for hand tapping.
I do use the machine to line up and start the taps after drilling the hole to
be sure it's started straight.

Speaking for myself, I will be buying the Spiral Point taps from them.
I never checked Enco. :?
Thanks for the info!!!

In the CNC machine I run at work EVERY tap is a Spiral Flute
They eject the chip via the spiral just as a drill bit does.
For aluminum they are perfect! The cylinder heads we are making on
my machine right now are aluminum and get 2) blind holes tapped
9/16-12 The machine spins the tap 250RPM to the bottom of the hole
and back out.

I don't know just how small they make the spiral flute taps.

Rick

 

[lugnut]

I think I'll order a couple of Enco's spiral fluted taps, They have them down to 2-56 and that's as small as I want to use. I'm going to take your advice and order some spiral point taps also..
I haven’t ordered any thing from Enco all month. By the way their Free shipping on $50 plus orders Code for October is WBCT7 It just has to be less than 85 lbs.
Mel

 

[rake60]

I'll have never tried a Spiral Flute Tap that small.
But I can promise you I WILL be in about 3 days! :wink:

Rick

 

[Lew Hartswick]

Spiral point bottoming seems a little "strange" to me since the chips are
pushed ahead of the tap in a blind hole the wad of chips would prevent
getting anywhere near the bottom.
For through holes they are even better than sliced bread and in some
respects even better than that other thing often comapred to.
Of course if you have depth to make the hole realy deep to accomodate the
chip wad go for it.
I just a few weeks ago used my first thread forming tap. Wanted to tap
two holes in some large knobs (in Aluminium) and with the small shaft
hole of only 1/4" there wasent enough room for the chips from a spiral
point so bought a 10-32 forming tap. Worked great. I did the taping with
the part in the mill vise right after drilling the hole so everything was
ligned up perfict. [ Note: drill sizes are diferent than for cutting taps ]
...lew...

 

[rake60]

That is a VERY good point Lew!
You have to clear the chips. The newer Spiral Tip Bottom Taps have a
wider flute at the tip than the older types to accommodate that. Even at
that, I will back them out a couple times to blow the chips out on a
deeper than average hole.
Tapping is like threading. Everybody idea of what works best is
different. What works best for the individual is best for them.
We all have a different feel for a tap handle, as well as a different ear
for the sound of a click that would indicate a chip is loading up.

I really like the direction this discussion is heading.
We all break taps. Anyone who has never broken a tap has either tapped
very few holes or their just plain lying to you.
The book tells you "1/4 turn in then 3/4 turns out to break and clear the
chip." Is that always best?

Rick

 

[wareagle]

Tap breakage? Somewhere I read or was told that you won't break a tap until it is the last hole of the part you are making. :x

What I have found that works best for me is to run the tap in two or three turns, then work it the remaining depth by doing a half turn, then backing it out three-quarters, and repeating the cycle until the threads are at the proper depth. On small taps, I have also chucked the tap in a drill chuck to a little more than hand tight, that way if the tap binds it will slip (theoretically) in the chuck before snapping the tap.

The use of a tapping fluid helps immensly. I personally like to use Tap Magic, but will use WD-40 or another oil (whatever is handy at the time) when tapping holes. On rare occasion, I'll tap the holes dry, but that is for thin pieces with through holes.

Okay, so my question to throw in the pot is: Does anybody like use or like thread forming taps? And what is the difference between them and "normal" taps?

 

[mklotz]

If you want to avoid breaking taps, especially small ones, I recommend that you build some tap guides like the ones shown below.

Each guide has a free wheeling pin at the top that is grasped in the drill chuck after drilling the pilot hole. The body of the tool, which holds the tap, turns and slides up and down freely on this pin.

On the far left is a finger operated one for 0-80 and 1-72 sizes. It has a single hole to fit the common shank size on my taps of this size. A setscrew bearing on one of the tap's flats holds the tap in place.

Next to it is a slightly larger version fitted with "collets" so it can take several sizes of tap shanks (00-90 and 2-56 primarily). The (removable) black screws can be used for a little extra torque when needed but I almost never use them.

The advantage of these two holders is the fact that one can't exert much torque with one's fingertips so overtwisting the tap just can't happen. The guide pin, of course, prevents one from tilting the tap side-to-side - a major cause of breakage.

The one in the middle is for somewhat larger taps - nos. 3, 4 and 5 primarily. The handles provide for a little more torque but not too much.

The one on the right is for the bigger taps and is also set up with "collets". It's major advantage, and the prime reason I made it, is its low height profile so it doesn't eat up all the headspace on my mill drill.

I also use the guide pin principle for making tap extenders.

Here again, a guide pin is fitted and the tap is secured with a setscrew. A flat on the shaft allows the small tap wrench to lock at any point on the extender to provide torque.

The guide rod is only 1/4" diameter so the whole unit functions like a pulley tap, which can be pricey.

 

[mklotz]

Just a heads-up...

If you do want to experiment with thread FORMING taps, the DRILL program on my page can be used to calculate the correct tap drill to use.

 

[lugnut]

Marv, THANKS you have helped a bunch! So now instead of just dinking in the shop tomorrow, I’ll try to make some of your tapping tools.
Mel

 

[rake60]

Does anybody like use or like thread forming taps?
And what is the difference between them and "normal" taps?

Thread Forming Taps are in a class of their own. The first time you see
one, you'd doubt that it could tap a hole. It has no flutes or cutting
edges. Instead of removing material to cut the thread, it displaces
the metal to form the thread. Enco has them available
down to 0-80 for $15.53Ea. Their not cheap! Since they don't actually
"cut" there are no chips to deal with. As has already been mentioned here
the drilled hole is larger than the hole drilled for a cutting tap.
They are designed for soft metals.

Rick

 

[shred]

My little mill doesn't usually have enough Z travel to tap in the mill, so I end up tapping by hand Making a simple tapping block has helped immensely, and they're dead easy in the lathe-- face off a short length of stock and drill a hole through it. One size works for most of the small taps.

 

[mklotz]

Shred,

I'm not sure what you mean by a "small mill" but if you're talking about something of Sherline or Unimat proportions, you might appreciate a technique I used when I only had a Unimat.

The Unimat has a round column so moving the head loses registration. Also the spindle downfeed is less than an inch so the chuck must be fairly close to the work when drilling.
Since the spindle bore is slightly larger than 1/4" (7 mm perhaps), I would mount the tap in a hole drilled in a length of 1/4" rod. This was then passed down from the top of the spindle (a la a drawbar) and out the drill chuck. With the chuck clamped on the rod and the belt removed from the spindle pulley, the Unimat was turned into a very nice in situ tapping machine without any loss of registration.

 

[lugnut]

shred, What mill do you have? If it's one like the Grizzley or HF mini mills you can gain about 3 inches of "Z" by replacing the rack with a longer one from Little Manhine Shop, $20. I just fixed mine and made a lot of differance in the machine.
Mel

 

[shred]

I'm running a Taig mill. There are a few tricks you can do to get some extra Z, but it's only got 9" to start with, then you add in the spindle and vice and workpiece and such and pretty soon you have to move off the table just to load a drill bit...

I've considered doing something like Marv's idea-- making tap-holders that fit one of the collets, but lately I've been doing pretty well with the old tapping block and finger-torque left over from my days as a rock climber for the little suckers.

 

[Julian]

Hi Guys,

I only use metric taps at the moment because they suit all my present work. In england if you want any tap ever made you go to Tracy Tools in Dartmouth but you pay the price £5 for a decent m4 in hss. I go to the model engineering fairs at Warwick in October and Harrogate in May. I go to Poops and buy Hss taps in m3, m4, m5, m6,m8 and m10 at 50p each. M10, m8 and m6 i will tap either by hand or with a drill depending on the job. Anything smaller is always by hand but thin taps still snap easily. m4 are a *****! At Warwick this October I did a deal and bought with them and bought fifty taps. My philosophy is buy cheap and throw away when broken or worn. Expensive snap just as easily and last the same amount of time. It hurts less to throw away 50p than £5 each time. I do the same with drill bits but use a decent one for the last drill through.
I am sure Poops would post across the water Chris Columbus established a half decent courier service over there!!!!LOL


Julian.