How-to: drilling and tapping holes

Started by Three se7ens, April 27, 2016, 03:25:54 AM

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gstours

Thanks for the great post,and references.  Ive always had fits trying to tap tiny holes in sst, and even mild steel.  Your pointers are sure to help.  Thanks for making this a great forum as we all learn by doing, and seeing :o

eguinn

 Something that I have found very useful for hand tapping threads is a little hand tapping block about 1" thick & however long & wide you want to make it. These are super easy to make from a scrap of aluminum, pick the flattest side of the material you can find, put it in your vise or whatever you have but make damn sure that the top surface is square to your machine or drill press spindle. You want to drill that hole a square as possible to this surface.Next you want to measure the major or biggest diameter of whatever tap you are going to use, drill your hole all the way thru, this allows your chip to fall out the bottom, drill about.003 to .005 bigger than your largest diameter on your tap, you want your tap to slide thru this block nice & easy without having a lot of slop. Deburr the hole top & bottom. Now to use this block simply put the flat side down ( the side you drilled the hole from), over the hole you intend to tap & gently start your tap. This pretty much insures you a good straight square threaded hole. I can't tell how many hundreds of holes I've tapped this way, I can't tell how many times these simple little blocks have saved my #### on jobs. How do I know about little things like this, well I've been doing Manual Mill & Lathe work building & machining small to medium sized Prototype & R & D parts for over 20 years in job shops & companies that had small machine shops in them, some of them we where doing things & parts that the CNC machine could not do or in a lot of cases we ( the guys in the Proto dept would not tell them how to do), I know it 's rotten to do this but it's was job security for us, like very precise angle holes drilled thru some very expensive parts. It was fun for the most part but sometimes these little complex close tolerance parts could & would get on your nerves. I'm retired from the industry now but I still have my tools. Ed

Makule

There's a whole lot of experience that went into the writing of this thread.  Had to learn it all the hard (expensive) way.
I used to be in a constant state of improvement.  Now I'm in a constant state of renovation.

oc1

Albert, I wish Adam (Threese7ens) and yourself would share would share more of your experiences with us.
-steve

Makule

What would you like to know?

Quote from: oc1 on May 21, 2021, 07:32:57 PM
Albert, I wish Adam (Threese7ens) and yourself would share would share more of your experiences with us.
-steve
I used to be in a constant state of improvement.  Now I'm in a constant state of renovation.