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Drill extension tool for wing attach holes.

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  • Drill extension tool for wing attach holes.

    This may have been described before and if it is repetition then apologies. Occasionally during the build we used the drill press as a lathe. We squared bushings by chucking the bushing and feeding it gentle into a file on the drill press tables. We do not have a lathe but with care work can be done accurately. We farmed out the lathe work of gas caps & shock strut parts and retaining ring groove. We purchased honed hydraulic tube for the shocks for about $30.

    We needed a drill extension to reach the wing attach holes. We tried to weld bits to a rod and it wobbled. Ions ago I had a Black & Decker drill guide with a long shaft extension where the chuck was removed & the shaft extension screwed on the drill & the chuck placed on the end of the extension shaft. That has disappeared so it was to replicate the extension shaft..

    We had a drill with a 3/8" chuck so we removed the chuck to find it had a 3/8" UNF thread. A piece of 1/2" x.065 4130 tube was found in the left over stock. I took a 3" UNF bolt & cut the head off. The threads were wrapped with tape and chucked in a drill press. A long strip of emery cloth was used to machine the shank of the bolt until it just fit. For safety use long strips and hold it by the ends so you do not get caught and pulled into the rotating drill press. The long strips keep the hands well away from the rotating drill press and if it did catch it is easy to let go to stay safe.

    The shank was constantly checked with the digital caliper to take it down evenly starting at the cut off. The bolt shank was worked to a uniform diameter along its length until it was snug slide fit into the tube with a gentle tap. Make it snug as any slop will can put the chuck off center. We silver soldered the shank in the tube with the thread projecting out to take the chuck. The chuck was installed. We put the extension in the drill and chucked a long bit to see if it spun straight. If it was off center the long bit would exaggerate any wobble or eccentricity. The drill extension was chucked in a 1/2" drill & the set up worked very well. The chuck cleared the fuselage just enough.
    Last edited by Glenn Patterson; 06-26-2016, 10:51 PM.

  • #2
    Here is what I put together with a pc of 3/8 CF and a chuck I stripped off of a burned out air drill. There is a little run out on the chuck but it worked fine for me. I will gladly send this out to another builder if interested. You will have to find your own chuck key, which shouldn't be a problem. Then send it back when finished or to another builder.
    Al
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    • TrueAirSpeed
      TrueAirSpeed commented
      Editing a comment
      Al, that would help since I'll be doing the wing thing in week or so. PM sent.

  • #3
    It is fun to get a chuck to spin true on an adapter w/o access to a lathe to either thread a shaft straight or to turn down a 3/8 bolt to fit in the tube.

    We found the 18" length of 1/2 x .065 4130 tube in our left overs & bought a couple bolts to play with as the threads in bolts are rolled in accurately.

    Not sure where the tube was used in the BH but it was a leftover from something. If I could make a drill extension with the aid of a drill press then others may as it is material, shop equipment & processes available to scratchbuilders.
    Glenn

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    • #4
      Another way to make an extension. 5/16 x .049 tubing can be tapped 1/4x28 thread so you can use threaded drill bits and reamers. Make it as long as you want. 3/8 x .083 can also be used if you want it stiffer but you need to open up the i.d. slightly.

      Doug
      Scratch building Patrol #254

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