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Shop Tip: A Fixture for Drilling Holes in Round Stock

Here’s a handy weekend metalworking project for you!

This is a device to drill cross holes in round stock. It is not to be used when great accuracy is needed. This is a simple way to drill cross holes in axles and other round stock easily. I started this project as a trial to see if it would work with the idea of eventually remaking it neater. However, it works so good that I just use it as it is. Someday, I hope to remake it to higher standards.

DrillRndStk1

 

I made this from some 1/2” aluminum flat. The drill guides are made from .750” hex steel. They are about 1.250” long with 1/2-13 threads. The guides are not hardened, so when they wear a little, either drill out to next larger drill size, or they are easy to re-make. The V-groove in the bottom section is 60 degrees.

DrillRndStk2

Here is a piece of 5/16” brass rod clamped ready to drill. I have removed two side pieces to bring the fixture into range for smaller stock. The extra side pieces are shown at the left. The side pieces are slotted so they are easy to remove and replace without removing  the tightening screw wing-nuts. Simply turn down the drill guide to hold the stock and commence drilling.

DrillRndStk3

Here the 2 sides pieces have been re-inserted to make the fixture larger so that a hole can be drilled in a 1” piece of brass round stock. I have made three drill guides of different hole sizes. You can also drill a smaller hole and then enlarge it easily. I have used this fixture in my drill press and it also works with a regular drill. It is portable so it can be used wherever the work is to be done.

 

Directions for use: Use the number of side pieces so that stock to be drilled fits in fixture. On my prototype, the center of the hole is .750” from the front edge and the back edge. Mark the position of the hole to be drilled then add .750”. Then tighten down the drill guide with a wrench. Drill hole.

 

Construction Details: The size of the top and bottom is 1.5” x 3”. The stud screws are 3/8”-16. The holes for the stud screws in the bottom are through holes but are tapped so that the threads don’t finish. That way the studs are tightened against imperfect threads and don’t unscrew when you move wing nuts. The center hole is tapped 1/2”-13. Top and bottom are marked front so that they may be replaced in proper position.

 

Submitted by:

James R. Instone

 

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About joutrock

Retired. Hobby machining.

15 comments

  1. Jim

    A couple of photos attached of my jig.  I think the main difference to yours is that my spacer blocks have holes instead of slots.  Other info: The guide is from 24mm S1214 hex (free machining steel – wonderful material to machine, and produces very smooth threads), and has an M16x2 thread, and the long bolts are M10 316 stainless.  The v-slot was made using a 90deg router bit.

    regards

    Dave

    IMG_1799-small.jpg

     IMG_1798-small.jpg

  2. Zipper said
    Jim

    A couple of photos attached of my jig.  I think the main difference to yours is that my spacer blocks have holes instead of slots.  Other info: The guide is from 24mm S1214 hex (free machining steel – wonderful material to machine, and produces very smooth threads), and has an M16x2 thread, and the long bolts are M10 316 stainless.  The v-slot was made using a 90deg router bit.

    regards

    Dave

      Hi Dave

    Thanks for the pics. I like your choice of materials. You did a good job of making the project. I will try some S1214 on my next project. Like most of my projects, I only provide the idea, then leave the actual construction up to the builder. This can provide many new ideas. Thanks again.

    Jim Instone (joutrock)

     

  3. Very nice work Dave, thanks for sharing!

    Is S1214 similar to 12L14? I’ve had good luck with 12L14 recently.

  4. Thanks Tyler

    To be honest, I was only aware of it being referred to as “free machining steel”.  I am not familiar with 12L14.  When I requested a quote for various sizes of round bar and hex, the supplier emailed me a table with the material spec as S1214.  It is such a pleasure to machine that I could just make a pile of swarf for the fun of it.  ;-)

     

    From I can see though, 12L14 has lead (0.15-0.35% lead), whereas S1214 is resulphurised/rephosphorised.  Have a look at the following:

    http://www.globalmetals.com.au….._Guide.pdf

    http://en.wikipedia.org/wiki/F…..ning_steel

     

    Thanks for your question though – now I know more about FMS after having a bit of a dig.

    rgds

    Dave

  5. Jim

    One other thing I did, is that I slightly oversized the stock for the thread on the drill bit guide (about 16.15mm) and when I cut the M16 thread, I spread the die as much as possible in the die handle using the centre grub screw, to get a slightly oversized thread (ie OD).  I was prepared to relax the grub screw if it was too tight and cut a bit more off the thread, but it resulted in a very nice snug fit of the guide in the aluminium block, which must help with accuracy.

    I also sandblasted the remaining hex part of the guide.

    rgds

    Dave