Square Peg, Triangular Hole: Holding a Small Tap in a Drill Chuck

**rgsparber** · May 29, 2022, 08:35 AM

When tapping small holes, it is handy to tap right after drilling the tap hole. You will quickly find that holding the tap in the drill chuck doesn’t work well and can damage the chuck.

I have a solution using a strategically placed bit of copper wire.

If you are interested, please, click here

Your comments are welcome. All of us are smarter than any one of us.

Thanks,

Rick

**mklotz** · May 29, 2022, 09:55 AM

A clever and expedient technique but turning the chuck on my mill by hand doesn't work well with my 80 year old hands.

Like you, I decided that the best time to tap a hole is while it is still aligned with the axis of the drill that made the hole. The pointed tap wrench guide thing was invented by a mutant with three hands. Piloted tap holders are commercially available but they eat up too much headroom when installed in the drill chuck. My solution was to make low profile tap wrenches with a built-in pilot that could be grasped in the drill chuck. A number of variants of this idea are described here...

Tap holders

The simplest of these has a fixed size hole to hold the tap which is secured with a set screw bearing on one flat of the square drive. Smaller taps have the same shank size...

Standard Tap Dimensions (ANSI Shanks) - Tapmatic Corporation

so this fixed hole size works well. For the larger taps, shank size varies so I made a tap handle that accepts collets to accommodate the various sizes. Since I knew I would need to made a number of collets, I chose the simplest design I could imagine. A bit of steel rod is drilled to a sliding fit on the tap shank. Then a bit of the rod is cut away to allow the setscrew to bear on the square drive.

**DIYer** · May 30, 2022, 06:14 AM

Thanks rgsparber! We've added your Tap Holding Method to our Tapping and Threading category,
as well as to your builder page: rgsparber's Homemade Tools. Your receipt:

Tap Holding Method by rgsparber

tags: chuck, tapping, holder

**rgsparber** · May 30, 2022, 07:25 AM

Originally Posted by mklotz

A clever and expedient technique but turning the chuck on my mill by hand doesn't work well with my 80 year old hands.

Like you, I decided that the best time to tap a hole is while it is still aligned with the axis of the drill that made the hole. The pointed tap wrench guide thing was invented by a mutant with three hands. Piloted tap holders are commercially available but they eat up too much headroom when installed in the drill chuck. My solution was to make low profile tap wrenches with a built-in pilot that could be grasped in the drill chuck. A number of variants of this idea are described here...

Tap holders

The simplest of these has a fixed size hole to hold the tap which is secured with a set screw bearing on one flat of the square drive. Smaller taps have the same shank size...

Standard Tap Dimensions (ANSI Shanks) - Tapmatic Corporation

so this fixed hole size works well. For the larger taps, shank size varies so I made a tap handle that accepts collets to accommodate the various sizes. Since I knew I would need to made a number of collets, I chose the simplest design I could imagine. A bit of steel rod is drilled to a sliding fit on the tap shank. Then a bit of the rod is cut away to allow the setscrew to bear on the square drive.

Marv,

As usual, very well done solutions. They are both functional and great looking.

Thanks,

Rick

**uv8452** · May 31, 2022, 12:59 AM

"...reasonably well centered." The geometry of centering a triangle to a square is not obvious. But I liked the surprise. Thank you for that! Perhaps I find an explanation.

**rgsparber** · May 31, 2022, 06:04 AM

Originally Posted by uv8452

"...reasonably well centered." The geometry of centering a triangle to a square is not obvious. But I liked the surprise. Thank you for that! Perhaps I find an explanation.

This surprised me too which is why I ran that 6-32 tap all the way in to be sure it was true. A possible answer is in plain sight - the copper wire covered both the square and round part of the shank. The jaw compressed both. The jaws on the round part would center the tap.

Subsequently, I wanted to know if copper over just the round part of the shank was sufficient. I used the wire on a 1/4-20 tap. Then I drilled a #4 hole in the aluminum. With the tap tightly in the jaws, I had no trouble tapping in one inch with no slippage. I used a close fitting rod in one of the chuck's key holes to get the needed torque.

Since I can drive a 1/4-20 tap this way, I expect it will work on smaller taps too.

Rick

**Jon** · Jun 3, 2022, 03:15 PM

Congratulations rgsparber - your Tap Holding Method is the Homemade Tool of the Week!

Clever, simple, cheap, reusable, and minimalist - a great solution overall.

Some more nice tools from this week:

Small Pipe Welding Fixture by Frank S
Mini Mill Motor Upgrade by Guy Marsden
Demagnetizer by tonyfoale
Powered Sheetmetal Shears by diy creative crafts
Center Punch by RCTURKA
Gib by Rustinox
Bevel Square by ttmrj
Heavy Wire Twister by orioncons36
Vise by Kwandotechnic
Wood Vise by Didpoolhall
Bench Grinder by h7eh7e

rgsparber - We've added your tool entry to our All Homemade Tool of the Week winners post, and you'll be receiving a $25 online gift card, in your choice of Amazon, PayPal, or bitcoin. Please PM me your current email address and award choice and I'll get it sent over right away.

More importantly, this is your 10th Homemade Tool of the Week win! I've just added the golden wrench-on-pedestal graphic to the awards showcase in your postbit, visible underneath your avatar.

You join these seven other 10-time winners: rossbotics, Christophe Mineau, mklotz, Vyacheslav.Nevolya, Tuomas, tonyfoale, and Stevohdee. Congratulations again and good job

Here are all 10 of your Homemade Tool of the Week winning tools:

CNC Controller by rgsparber

tags: CNC, controller

Irrigation Flow System by rgsparber

tags: farm and garden, electronics

Software Defined Edge Finder by rgsparber

tags: electronics, edge finder

Drill Press Clamp Modification by rgsparber

tags: drill press, clamp

Flight Data Recorder by rgsparber

tags: electronics

Radius Fixture by rgsparber