Adjusting the "Universal delay drilling tool"

Discussion in 'The Watering Hole' started by Wayco, Jul 12, 2015.

Help Support The Rocketry Forum by donating:

  1. Jul 12, 2015 #1

    Wayco

    Wayco

    Wayco

    Desert Rat Rocketeer TRF Lifetime Supporter

    Joined:
    Mar 23, 2011
    Messages:
    3,267
    Likes Received:
    141
    Location:
    Goodyear, AZ
    I have two of the new Universal delay drilling tools, and the drill bit is 1/16" longer on one than on the other. Measuring from the base of the knob, one is 2 1/8" and the other is 2 3/16". Since 1/32" is one second difference in the delay, that's a 2 second variance in these two tools. Anybody know what the correct length of the drill bit should be?

    [​IMG]

    [​IMG]

    I can see where there is a set screw in the knob, so it should be easy to adjust, I just don't know what the correct length is.
     
  2. Jul 13, 2015 #2

    gltruett

    gltruett

    gltruett

    Well-Known Member

    Joined:
    Jan 20, 2014
    Messages:
    89
    Likes Received:
    0
  3. Jul 13, 2015 #3

    rharshberger

    rharshberger

    rharshberger

    Well-Known Member

    Joined:
    Oct 13, 2014
    Messages:
    8,161
    Likes Received:
    706
    Gender:
    Male
    Location:
    Pasco, WA
    I know to adjust the RDDT tool you just place the tool on a flat surface and adjust the bit till it touches the surface, doenst matter wether you use the 4 second or 8 second end on the table/surface, the drill bit handle should sit flat on top the adapter ring. UDDT should be similar.

    I recently had my drill bit on the RDDT come loose and it removed a small amount from the delay, not the 4 seconds I needed needless to say the rocket (my sons Crayon Bank Rocket) slammed into the ground rather hard.
     
    Last edited: Jul 13, 2015
  4. Jul 13, 2015 #4

    Wayco

    Wayco

    Wayco

    Desert Rat Rocketeer TRF Lifetime Supporter

    Joined:
    Mar 23, 2011
    Messages:
    3,267
    Likes Received:
    141
    Location:
    Goodyear, AZ
    I use the same method for the RDDT, but the UDDT has to fit down into the forward closure and cannot be adjusted like that. I used this method that I found on the thread that gltruett linked above:

    After I set it, I measured it with my calipers using a single washer on the knob, this gives you a flat surface to set your caliper on. My measurement was 2.086, pretty close to these:

    Thanks for the link!
     
  5. Apr 17, 2019 #5

    amiliv

    amiliv

    amiliv

    Active Member

    Joined:
    Jul 2, 2018
    Messages:
    40
    Likes Received:
    6
    Hmmm... This smells about the length of calibrated drill bit for the RMS tool (both 18-38mm and 54mm tools). I wonder if the difference in body length of the universal and RMS tools is the depth of the charge well. If that is true, it would mean knob with drill bit is interchangeable between the two, and one could calibrate length of the drill bit for the universal tool directly by inserting it into RMS tool.

    The above is just speculation. I.e. don't do that until somebody confirms it is actually true!
     
  6. Apr 17, 2019 #6

    amiliv

    amiliv

    amiliv

    Active Member

    Joined:
    Jul 2, 2018
    Messages:
    40
    Likes Received:
    6
    Got reply from AeroTech's support. The UDDT body is shorter than RMS DDT body. The difference in length is the depth of the ejection charge well. If you have RMS tool (or a friend with RMS tool, or borrow it from someone at the launch) you can calibrate UDDT using the RMS DDT, following exactly the same procedure:

    1. Take the knob and drill bit out of UDDT.
    2. Loosen the set screw.
    3. Put the body of RMS DDT on flat surface.
    4. Insert UDDT drill bit into RMS DDT all the way down so the tip is flush with the bottom end of the tool.
    5. Put the knob back onto top of the drill bit and push down till flush with the top end of the tool.
    6. Tighten the set screw; make sure to not move drill bit or knob when tightening it.
    7. Take the knob and drill bit out. The exposed part of the drill bit should be exactly the length of the RMS DDT body.
    8. Put it back into UDDT.
    Do not use washer during calibration!

    While the method of using the motor and two washers to calibrate UDDT should work too, simply using RMS DDT to calibrate UDDT is nicer and simpler. You can do it anytime, no need to have the motor and/or take it out of the sealed bag, if all you want to do is to calibrate the tool before you go to launch.
     
    Last edited: Apr 17, 2019

Share This Page