Tapping Fixture for a Drill Press

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About: I miss the days when magazines like Popular Mechanics had all sorts of DIY projects for making and repairing just about everything. I am enjoying posting things I have learned and done since I got my first ...

A tapping fixture allows more precise cutting of threads with a tap than can be done by hand. I adapted a drill press so the quill can be used as the heart of a tapping fixture. Here is a commercial tapping fixture. The photo shows my tapping fixture ready to use. My attachment handle gives me leverage for turning the quill. The arms on the quill allows me to keep some downward pressure on the quill. This helps the tap bite into the metal when cutting.

Materials

  • 1 1/2 inch black iron pipe
  • 5/16 x 3/4 inch bolt
  • 1/2 inch black iron pipe

Tools

  • Metal cutting bandsaw
  • Center punch (spring loaded)
  • Drill and bits
  • 5/16 x 18 inch thread tap
  • Metal lathe
  • MIG welder
  • Digital caliper
  • Spring clamp

Step 1: Size the Tube or Pipe

1 1/2 inch black pipe has an internal diameter very near to the diameter of the lower part of the drill chuck on my drill press.

I cut a piece from the pipe about 3/4 inch wide. See the second photo.

Step 2: Enlarge the Internal Diameter to Fit the Chuck

I am thankful to have an old Atlas metal lathe I could use to enlarge the internal diameter of the pipe until it fit over the lower part of the drill chuck. A digital caliper was very handy for checking progress. I also smoothed the saw cuts with the lathe. The second photo shows the piece of black pipe enlarged enough to slip over the end of the drill chuck.

Without a lathe, it would be possible to use a file or a grinder (with a cylindrical stone) to enlarge the internal diameter, but some patience would be required.

Step 3: Attachment Locking Mechanism

Something needs to lock the pipe collar to the drill chuck and provide leverage for turning the drill press quill when cutting threads. I chose something very simple.

The holes in the chuck for the chuck wrench are 5/16 inch in diameter. I used the end of a drill bit to determine the size. See the first photo.

I used a digital caliper to determine the distance between the bottom of the part of the chuck turned with the chuck wrench and the center of the holes for the chuck wrench. The second photo shows a faint line scratched into the outer surface of the black pipe collar. I used a spring loaded center punch for drilling exactly on that line.

I began with a very small drill bit and worked up to larger bits until I had drilled a hole about right for tapping to make threads for a 5/16 inch bolt. I tapped the threads. See the third photo.

Test the fit with a 5/16 inch bolt. See the fourth photo. The end of the bolt screws into the hole for the chuck wrench.

Step 4: Weld the Bolt Into the Handle

I used a spring clamp to hold the pipe collar to a piece of aluminum angle in a vise. I slipped 1/2 inch black iron pipe over the head of the bolt and tack welded the 1/2 inch pipe to the bolt.

I finished welding the bolt inside the 1/2 inch pipe. See the second photo.

Cut the pipe handle to length. See the third photo.

The fourth photo shows my attachment ready to use.

Step 5: Use

A drill press vise clamped to the drill press table is handy. Add a little downward pressure on the quill arms as if you are drilling a hole. Use the fixture handle to turn the quill and begin cutting threads. Because the chuck has three jaws but the tap is made for a four sided holder, it is difficult to keep the chuck from slipping on the tap. I could carefully grind three flats on the tap, or I could use the tapping fixture to start threads and then finish in a vise.

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    22 Discussions

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    sbelectrics

    19 days ago

    Nice use of a drill press to avoid 'drunken threads' as our metalwork teacher used to call them. However, unscrewing the handle each time to move it around the chuck must be a bit of a chore? Could you not spring-load the handle so that it simply pulls out to move it around and the spring holds it into the hole in the chuck when released? (Or even just make the handle telescope in and out by about 5mm to enable pull-to-rotate and push-to-tap operation?)

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    Phil Bsbelectrics

    Reply 18 days ago

    Once in place for use, there is no need to remove the handle until finished tapping threads. I should have made it a little shorter so it clears the arms that lower the quill, but I can easily and quickly remove the control arm in my way and use one of the other two arms.

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    sbelectricsPhil B

    Reply 14 days ago

    Sorry about that; it's just that in the photograph it doesn't appear that the handle will pass the drill pillar. However, using your idea as the basis, I have now found a spare adjustable side handle from an old SDS drill which clamps nicely onto the knurled part of my pedestal drill chuck so that I can use that to do the same job in future. (The advantage of turning the outer section of the chuck is that it tends to increase the clamping force on the tap or drill as it is turned.)

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    Phil Bsbelectrics

    Reply 13 days ago

    I hope it works out well for you. A great thing about projects on this site is readers can adapt according to materials, tools, and skills available.

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    jwzumwalt

    17 days ago

    Really nice tip! It makes you wonder why this isn't included when you buy a drill press, or why they are not sold as an accessory... though, I think haveing 3 or 4 handles (or even a continious ring and spokes) would be an improvment.
    I'll be making one for myself next weekend!

    1 reply
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    Phil Bjwzumwalt

    Reply 17 days ago

    I poked around on the Internet before posting this and found using a drill press as the foundation for a tapping fixture is not at all uncommon. If I were to make a free standing tapping fixture, there would be a number of challenges already resolved by the makers of the drill press. My biggest problem is the tap slipping in the chuck before I can tap more than a couple of turns. But, that does give the start of a straight set of threads easy to finish well by hand. I find the one arm for turning the quill is very adequate.

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    jdhoff_comcast

    Tip 19 days ago on Step 5

    There are also commercially made socket-type tap holders available although these require more space between chuck and piece to be tapped.

    1 reply
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    tonyfoalejdhoff_comcast

    Reply 17 days ago

    I use those on a tapping head that I made, they can be seen at https://www.instructables.com/id/Manual-Thread-Tap...
    If you get one of those hex to 3/8" square drive adapters which are made to use sockets with battery screwdrivers with hex fittings then the hex will fit in the drill chuck and not slip, the socket-type tap holder will not allow the tap to slip.

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    efoster6

    19 days ago

    Looks great but the idea of the bar with the screw doing the turning and 5/16 is only a small thread I would be more inclined to weld the handle on and put the locking and drive screw on the other side and use a larger size with the end turned down to make a good fit into the chuck and weld a nut on the other side so that your not pushing on the thread if you can follow what I mean

    2 replies
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    tonyfoaleefoster6

    Reply 17 days ago

    I was thinking the same as I read the post.

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    Phil Befoster6

    Reply 18 days ago

    I wanted to keep this as simple as possible.

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    lemondropkid

    18 days ago on Step 5

    Thanks, certainly helps me out, always have difficulty starting a thread. The idea from Syncubus below is also a big help.

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    Syncubus

    19 days ago on Step 5

    While this is interesting and I liked your clever mounting method, I've often seen people chuck a short, pointed tool in a drill press (or milling machine) and use that in the indentation in the back of the tap (nearly all taps have this indentation) to 'steer straight and provide quill pressure' while using a regular tap wrench on the tap. This avoids the 'square peg in a hexagonal chuck' problem and requires a lot less storage space.

    Here's an example: https://www.instructables.com/id/tapping-a-straight-hole-with-the-aid-of-a-drill-pr/

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    lemondropkidSyncubus

    Reply 18 days ago

    Great idea, why didn't I think of that ! Thanks for the example too.

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    Phil BSyncubus

    Reply 18 days ago

    Interesting idea. Thank you for the link.

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    AlyssonR2

    18 days ago

    I did something similar a good few years ago using a defunct hand drill with a 5/16 chuck and a simple drill-press attachment.
    Perfect for those small tapped holes in sheet metal and small parts.

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    Phil BAlyssonR2

    Reply 18 days ago

    That would work, especially for small diameter taps.

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    MikeH158

    18 days ago

    While that's a nice accessory.....in the past I've just stuck either a metal rod, or even a drill bit in the check key hole to turn the chuck.....

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    Phil BMikeH158

    Reply 18 days ago

    In the past I struggled along by using the chuck wrench.

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    pgs070947

    19 days ago

    Interesting. Whenever I see bars of metal sticking out of drill press chucks or whatever, I get nervous, like forgetting to remove the chuck key.
    I did a lot of prototyping professionally and the drill press was an essential part of kit.
    I also had a lot of panel tapping to do, so added a tapping device called a Tapmatic. You simply fitted the tap and slowly and carefully lowered the tap into the hole. A clever clutch mechanism ensured that it was a safe business. However, there was a point in the operation where it was necessary to stop the rotation and despite the clutch, doing it manually always seemed risky.
    In the end, I added a metal bar that would swing round, catch the pillar, and the Tapmatic did the rest.
    I still use the drill press to tap holes, but strictly with no power applied and simply rotate the chuck while lowering the tap.
    I must admit, I didn't read all the way through, but having seen some nasty injuries involving rotating machinery, I trust you have checked it all out. If so, a worthwhile project