Drill 9/32" holes


Senior Member
What do these figures mean in the expression "Drill 9/32" holes"? Does it mean to drill nine holes which are 32' deep or this is the number of holes (9 out of 32 holes)? 9the context is below.

Decks thinner than 1/4"
Use a Cannon deck plate to prevent deflection and add stability to decks thinner than 1/4". Use the deck plate as a template to mark the hole locations.
If access to the underside of the deck is not available, the deck plate can be mounted using screws and wellnuts. Drill 1/2" holes. Use four 1/4-20 x 2" flat head screws and four wellnuts to mount deck plate as pictured. Tighten the screws so the wellnuts are firmly compressed.
Where the underside is accessible, the deck plate can be mounted using screws, nuts, and washers. Drill 9/32" holes. Use four 1/4-20 x 2" flat head screws, nuts and washers (flat and lock). Fasten plate to deck as pictured. To secure the mounting base to the deckplate use four 1/4-20 x 2" truss head screws.
  • sdgraham

    Senior Member
    USA English

    In the U.S. we have not yet embraced the metric system and most of our fasteners are based upon the Imperial system using inches.

    We also tend to use vulgar fractions in measurements. Thus, a 9/32 hole is nine 32nds of an inch (9 divided by 32). Likewise, one system of twist-drill sizes is expressed in fractions. So, one uses a 9/32 -inch drill to make a 9/32-inch hole.

    You didn't ask but a 1/4 -20-inch screw is a screw 1/4-inch in diameter (0.25 inches) with 20 threads per inch.

    Thus, your instructions are to drill holes 1/32-inch larger than the size of the screw.
    Last edited:


    Senior Member
    American English
    Drill as many holes as you need (four, I think, from the context). Each hole is to be nine thirty-seconds of an inch wide, slightly larger than the quarter-inch screws it instructs you to use.

    Edit: Beaten to the punch, and with more detail, by sdgraham.


    Senior Member
    English - U.S.
    If you have to drill these holes and you have only metric drills, use a 7mm drill. It will be very slightly smaller than 9/32". (9/32" is about 7.14mm.) The holes will be large enough to install the 1/4" screws that you may have been given with this item.
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