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Why should I use a straight drill for a tapered tap? I know the taper allows for a good seal ( we are working with air lines), but when put on the fitting, it only goes halfway in. We are positive that we have the right size drill and tap (we checked more than 10 times). Any help would be greatly appreciated.

Thank you,

Thomas L. Coy

That's the way it is.

Now worry about why you can't find the appropriate forum for a post.

tomlcoy wrote:Why should I use a straight drill for a tapered tap? I know the taper allows for a good seal ( we are working with air lines), but when put on the fitting, it only goes halfway in. We are positive that we have the right size drill and tap (we checked more than 10 times). Any help would be greatly appreciated.

Thank you,

Thomas L. Coy

Yup, what Marc said.

http://www.wimp.com/feynmanterms/

Here is the link where you needed to post. Lots of great questions and answers in here. http://www.shoptalkforums.com/viewforum.php?f=49

must be the right forum. you answered.

To the original question, there is a step you missed that many don't know about. After you drill the hole and before you tap it, you should run a tapered reamer down the hole. There are specific reamers designed for the standard tapered pipe threads.

tomlcoy wrote:....but when put on the fitting, it only goes halfway in.

Put the tap back in and keep going. Give it a couple more turns, then check it.