I purchased a complete tap set and am going to use it for the first time this weekend. Am working with a boss on my intake manifold.

Have not ever done this before and would appreciate any adivce on how to help this go well. i.e. do you just allow the tap to progress through the drill hole or should I keep pressure on it, etc...

Thanks in advance... Ed

 

You will need to keep some pressure on the tap. It's best to go a few truns in , then back it up a turn to clean the theads, then repeat. good luck.

 

Clean the hole as much as you can then use some light oil to lubricate the tap. Make sure you are straight up and down or your new threads will get messed up.

Bill

 

Make sure to use the long tapered tap first. Being a long taper there is a gradual cutting of the threads. The others having a short taper cut almost the whole thread all at once. If its a blind hole then redo with the blunt bottoming tap.

Make sure your starting straight.

I usually apply pressure for about 1- 2 turns. After that the thread should be started and the real cutting is happening. Half a turn in half out to clear the cutting. No pressure needed once its started screwing itself
Use something to lubricate the cutting tap.
Also aluminum can be 'sticky' where steel isn't. Aluminum can stick onto the cutting edge and jam, Backing off breaks the cutting curl off.

If you use a die for a thread chaser make sure you adjust it first on a good bolt. They can cut threads too tight or too loose. A thread chaser isn't adjustable. Looks like a nut.

 

practice on something that you don't care about first..

 

I like to use Relton Option1 Cutting Fluid

http://www.mytoolstore.com/relton/option1.html

 

Start as straight as possible, use a good taping compound, pressure only for the first few threads and then the tap pulls itself along. After a turn or two back out part of a turn to break the thread chip.
Don't force anything, if you feel the tap is getting hard to turn back up to clear the thread.
Make sure you are only turning the tap and not putting pressure on one side of the tap handle.
Taps can break easily and you don't want that.
Good luck.
I often use my drill for tapping small holes

 

Putting a small bevel on the hole will help the tap to start easier.

 

Probably the best advice.

 

Just an ever-so-slight chamfer with a countersink bit and you're GTG.

 

All of the above advice is good. A lot depends on the quality of the kit, are they good taps? If you have real cheap taps, you really need to pay attention to the tips above. My experience is that the more flutes on the tap, the easier they break. My company builds machines, and we use only two flute taps, and we tap holes with a variable speed drill motor.
Daffy

 

when you get good at it you'll be able to use a battery drill like i do!

 

I'm no machinist, but I've tapped a lot of holes.

To the best of my knowledge, there are approximately 3 different styles of taps for every size hole. They're numbered 1,2,3.

Sounds like you're tapping a blind hole.....the toughest to do, especially for a beginner.

The 1,2,3 taps vary in the taper. For a blind hole, you'll eventually need a #3 or a "bottom tap" that has full flutes all the way to the bottom of the tap. Most tap sets are #1's, your standard tap for tapping a hole THROUGH something. You'll probably have to buy a "bottom tap" if one isn't in your set.

Be careful and go slowly. If you break a tap, they're case hardened steel...very tough if not impossible to drill out, as they're harder than the drill bits you have. Chuck

 

All good advice and to add some more.

As chuck said the good sets come with 3 taps, starter, plug, and bottom tap. The taper gets shorter as you progress from one to the other. Many of the taps sets I see for sale do not come with the 3 taps, only a plug tap. The steel used isn't too good and they don't hold an edge for long. For home use they're ok.

Tapping holes was the 2nd thing we learned as kids in tech school, 1st was filing! We never used a power drill and I still don't- old school training I guess.

Tapping is dependant on the material being tapped, lubrication of the tap, tap quality, and type of hole. If you're tapping a through hole the chips will clear, if you're tapping a blind hole they will load up the hole so you have to be aware of that and clean it out. When you start use even pressure and go in straight. Once you get a bite then go CCW to clear the chips, go CW 1-2 turns, CCW, etc until you have a clean start. Once you get to the end move up to the next tap and continue.
If you feel it binding stop and clear it. If the tap gets loaded and you force it it will break and they are almost impossible to remove and will wreck the hole most times.

If you're tapping with a pipe tap do not go to the end. Pipe taps do not come in 3 piece sets like a machine tap. They are a different taper and you want to fit the pipe to the hole little by little until if fits enought to seal the threads. rule of thumb is about 1/2 way down the taper should be good.

If you're tapping into a hole with a rib or radius on the other side- be careful or the tap will catch and snap very quickly. Taps will follow the drilled hole. You can "play" and little with it but if the hole is on an angle don't expect to " bend" it straight, you'll break the tap.
It's not hard but like anything else you have to develope a feel for it.

Good luck and watch out for those chips!

Gary

 

Thanks for ALL OF THE ADVICE!!! Here is the Set I purchased... any thoughts?

Craftsman 39 pc. Standard Tap and Die Set
Sears item #00952382000 Mfr. model #52382
39 pc. SAE Carbon Steel set. Hardened, precision-ground and polished Carbon Steel surfaces make chip removal easy. Hex-shaped dies permit use of sockets and wrenches as well as die stocks. Learn more

 

 

I have several magnets, the kind you use to retrieve parts that you've dropped. Several are real small, about 1/4 inch diameter on an extending "pole".

I use the magnet to get the chips out of blind holes. Chuck

 

For the morning after
There are tap extractors. Looks like a bare tap with a sliding sleeve. The sleeve carries pins that fit into the gullets of the broken tap.
They are expensive but might be worth it on a special job.