Quick question about using a large tap

[stovebolt6]

I have to tap a hole in an exhaust manifold for a 3/4" bolt. I have the tap, but not a T wrench big enough for it. Even if I did, the hole is in a weird spot that wouldn't permit the use of a tap wrench anyway. However, I have a 12 pt socket that fits perfectly on the tap.. can I just use a regular ratchet? Don't have far to go, it's a coarse thread and maybe only need to tap 4 or 5 threads.

Thanks

 

[zkling]

What type of back end does the tap have? Hex or square? If the latter, I'd rather use an adjustable wrench to get full contact. Just make sure you get it started perpendicular. They do make hex drive taps, that are designed to do what you do. Otherwise, with a square end you would need a 8pt socket, correct?

 

[stovebolt6]

What type of back end does the tap have? Hex or square? If the latter, I'd rather use an adjustable wrench to get full contact. Just make sure you get it started perpendicular. They do make hex drive taps, that are designed to do what you do. Otherwise, with a square end you would need a 8pt socket, correct?

It's a square end. A 1/2" 12 pt socket fits on perfectly.

 

[greasemonkey44]

Use the socket. It's a very handy trick to have.

 

[Leaflessshadetree]

Be careful to keep it straight. A T handle or sliding breaker bar may work better than the ratchet.

 

[gungatim]

ditto above. Was just going to suggest to get a sliding t-bar instead of ratchet, two hands keeps it straight, a ratchet works but puts uneven stress around the tap as it spins

 

[Carla]

Be careful to keep it straight. A T handle or sliding breaker bar may work better than the ratchet.

Concur......also, wedge some shim stock, or even multiple thicknesses of aluminium-foil into the square drive of the socket, and the fit of the tap to the socket, to eliminate any 'wobble' inherent in the tap/tool assembly.

That will help your 'feel' to get the tap started in the existing threads with a minimum of chance for cross-threading it.....but thats still a little 'tricky'.....do be ever so careful.

cheers

Carla

 

[n8n]

Last time I was at a local speed shop the guy behind the counter was tapping a hole in an exhaust flange with a ratchet. He had a little socket that was 1/2" (or maybe 3/8?) square on one end and the other held the square drive of the tap. I of course was intrigued and asked who made it, the answer of course was Snap-On.

http://store.snapon.com/SearchResul...entName=All&Min=0&Max=0&FieldId=0&FieldValue=

Of course being Snap-On I really can't afford to buy them as infrequently as I need them, but I was patting myself on the back recently for being a completist and buying a 9/32" combo wrench to finish off my set; I found it to be perfect for turning a small tap. I also have some 8 point sockets which would be better, if the right size, than a 12 point socket for this use.

 

[kjbenner]

Last time I was at a local speed shop the guy behind the counter was tapping a hole in an exhaust flange with a ratchet. He had a little socket that was 1/2" (or maybe 3/8?) square on one end and the other held the square drive of the tap. I of course was intrigued and asked who made it, the answer of course was Snap-On.

http://store.snapon.com/SearchResul...entName=All&Min=0&Max=0&FieldId=0&FieldValue=

Of course being Snap-On I really can't afford to buy them as infrequently as I need them, but I was patting myself on the back recently for being a completist and buying a 9/32" combo wrench to finish off my set; I found it to be perfect for turning a small tap. I also have some 8 point sockets which would be better, if the right size, than a 12 point socket for this use.

I think those Snap-ons are made by Lisle.

Smaller sizes set: http://www.amazon.com/dp/B0002SRFOE/?tag=atomicindus08-20

Larger sizes set:http://www.amazon.com/dp/B000Q6SG4A/?tag=atomicindus08-20