Any difference between a 'bottom/blind' tap and regular tap?

[bgilbert]

Is there any difference between a 'bottom' or 'blind' tap and a regular ole off the shelf metric tap??? I am installing head studs and need to clean out the threads in the block. I bought a 12mm x 1. 75 metric tap from the store. I didn't see anything on the package or the other boxes at the store that mention 'bottom/blind' tap. Thanks.

 

[Greenleaf]

b,



The reg taps are slightly tapered to start a hole or "tap" a hole which is drilled to the proper dia.



A bottom tap is only used to finish tapping a hole that MUST be tapped to the very bottom the the (blind) hole. It's simply the same tap, 'cept it's blunt at the end as opposed to tapered.



I didn't know this untill I spoke with Scott @ the Smokehouse.

 

[Perrysburg_Dodgeboy]

Also a thru tap pushes the chips down thru the hole and a bottom tap pulls the chip out of the hole. So you do not want to use a thru tap in a blind hole as you will pack the hole with chips.

Don

 

[PToombs]

FYI, there is also a starting tap, which is even more tapered. You may need to go to a specialty store, fasteners or hardware, to find a bottom tap.

GL, Scott's house wouldn't be smokey if he quit runnin' his trucks in there! :-laf

 

[Paychk]

If you are careful you can grind off the taper on a starting or taper tap to make a bottoming. When grinding the tap it must remain cool, or you pull the temper out of it. When in use you must back the tap out every 1/2 - 3/4 of a turn to clear the debris, especially when you're close to the bottom of the blind hole.

 

[1stgen4evr]

There is also a 'plug' tap which has the correct taper to fit a plug into the hole for a seal tight fit. This is very much like a pipe tap but can be bought in any of the standard threads. Not all plugs are pipe thread.



There are different classes of fit and if you are doing anything to the threaded holes in your block, I recommend that you select a proper class of tap. Otherwise you could wind up with a sloppy fitting (over cut) hole. Hardware and parts house folks will not generally be aware of this difference nor stock anything but 'it will go in the hole catagory' taps.



This will also show up on the threaded holes in the Getrag housing. If you buy a standard metric tap to clean out the holes, the bolts will fit VERY sloppy in the holes.



If the tap you have seems to be cutting material at the top of the hole, STOP. You are screwing up.



James

 

[Perrysburg_Dodgeboy]

To clean out bolt holes

Hears a little trick for you, you can use a class 5 or higher bolt to clean out the treads by grinding 3 groves in the body of the bolt. Grind about ¼ of the diameter deep and about 1/8 wide taper the end about three treads back and run the bolt in the hole will light oil or kerosene. Works great!

Don

 

[BushWakr - RIP]

Geezz... . I had NO idea there were so many type's ... ... . this is good FYI stuff guys... .



pb... .

 

[tugboatphil]

I didn't know this untill I spoke with Scott @ the Smokehouse.

Greenleaf,



You are really starting to scare me. Either open the doors of the garage, or get medication.



By the way, has "Scott" started talking back to you?? :-laf :-laf

 

[Nate]

Yeah I didn't realize there were so many taps either. My brother is a machinist and he's explained all of this to me.

 

[jrjuday]

There is another type called "the neighborhood tap". If you break one of the previously mentioned taps in a blind hole, just head for the neighborhood tap!!

 

[Perrysburg_Dodgeboy]

There is another type called "the neighborhood tap". If you break one of the previously mentioned taps in a blind hole, just head for the neighborhood tap!!

:-laf Now that there is FUNNY :-laf

 

[boatpuller]

There is another type called "the neighborhood tap". If you break one of the previously mentioned taps in a blind hole, just head for the neighborhood tap!!

Is that neighborhood tap located in the neighborhood bar :-laf :-laf

 

[PToombs]

Isn't that the best kind of tap?

Did you guys know they make a tap extractor? 4 tangs inside a sliding tube with a hex drive on top. A guy at work has one, slide the tangs into the flutes on the broken tap, slide the tube down close, screw it out (allegedly). If it works it has to be better than the blue wrench method

 

[Rebel Ram]

Would anyone be interested in an M-11/16 Left Handed Metric bottoming Pipe tap?

 

[JLEONARD]

Question...

If you use a blind tap to clean out the threads... .

Do you need to put "never seez" on the bolt threads???????



:-laf :-laf :-laf

 

[Greenleaf]

ahhhhh....AH

AHHHHHHHHHAHAHAHAHAHAHAH



Slap'n my knee!

 

[PToombs]

Question...

If you use a blind tap to clean out the threads... .

Do you need to put "never seez" on the bolt threads???????



:-laf :-laf :-laf

That was really bad what's worse is I had to read it twice before I got it!