Register

If this is your first visit, please click the Sign Up now button to begin the process of creating your account so you can begin posting on our forums! The Sign Up process will only take up about a minute of two of your time.

Results 1 to 12 of 12

  1. #1

    Join Date
    Jan 2004
    Location
    portland, OR
    Posts
    81
    Gallery
    My Gallery
    Models
    My Models
    Ratings
    My Feedback

    what size drill bit for 1/4 20 tap?

    I am taping holes for my wing bolts, I have the 1/4 20 bolts and tap but can't remember what size drill bit I need to use.

    If its 1/4" I'm going to feel stupid.

    Thanks.
    \"build em\' crash em\' and build em\' again

  2. #2
    FLYBOY's Avatar
    Join Date
    Jan 2002
    Location
    Missoula, MT
    Posts
    9,033
    Gallery
    My Gallery
    Models
    My Models
    Ratings
    My Feedback

    RE: what size drill bit for 1/4 20 tap?

    Use a number 7 drill bit. If you don't have one, you will have to pick one up at the hardware store.
    Fly it till the wings come off.

  3. #3
    depfife's Avatar
    Join Date
    Dec 2001
    Location
    St. Louis, MO
    Posts
    5,057
    Gallery
    My Gallery
    Models
    My Models
    Ratings
    My Feedback

    RE: what size drill bit for 1/4 20 tap?

    Hole tapping requires odd size bits. This numbered bits are sized by wire gauge. Here is a link that shows a Craftsman set. You can buy them individually if the whole set is not needed.
    http://www.sears.com/sr/javasr/produ...id=00906819000

    Eric

  4. #4

    Join Date
    Nov 2002
    Location
    Rochester, MN
    Posts
    1,270
    Gallery
    My Gallery
    Models
    My Models
    Ratings
    My Feedback

    RE: what size drill bit for 1/4 20 tap?

    A #7 drill bit.

  5. #5

    Join Date
    Mar 2002
    Location
    Sugar Land, TX
    Posts
    439
    Gallery
    My Gallery
    Models
    My Models
    Ratings
    My Feedback

    RE: what size drill bit for 1/4 20 tap?

    themanimal

    This might be handy to you the next time you need to drill and tap a hole.

    Have fun flying

    Lee
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

Name:	Bz78159.jpg 
Views:	1163 
Size:	293.5 KB 
ID:	100004  
    Sugar Land, TX

  6. #6

    Join Date
    Jan 2003
    Location
    Spring Hill, FL
    Posts
    4,518
    Gallery
    My Gallery
    Models
    My Models
    Ratings
    My Feedback

    RE: what size drill bit for 1/4 20 tap?

    a 3/16" bit is close enough if you're tapping wood.
    Work is what I do for the love of it. A job is how I pay for it.
    Please visit AirfieldModels.com

  7. #7

    Join Date
    Dec 2001
    Location
    Waynetown, IN
    Posts
    2,473
    Gallery
    My Gallery
    Models
    My Models
    Ratings
    My Feedback

    RE: what size drill bit for 1/4 20 tap?

    OR if you are tapping wood, and you are going to go buy a bit, USE A NUMBER 8 INSTEAD OF 7....I have found that going down one size when tapping wood works VERY WELL....A #7 gives you the proper contact percentage for metal.
    CUSTOM GIANT SCALE BUILDER
    PROTOTYPE MODEL BUILDING for full scale aircraft
    current project can be seen at http://www.geversaircraft.com

  8. #8
    MinnFlyer's Avatar
    Join Date
    Apr 2002
    Location
    Willmar, MN
    Posts
    28,519
    Gallery
    My Gallery
    Models
    My Models
    Ratings
    My Feedback

    RE: what size drill bit for 1/4 20 tap?

    Cafeen's right, if it's wood a 3/16 will work. A 13/64 is better yet. (it's only 2 thousanths of an inch larger than a #7 -- That's about the thickness of a human hair) (No, not a RED hair)
    Mike B. AMA# 42400 www.gettingairborne.com
    Ultra Sport Brotherhood #2 - Waco Brother #188 - Cub Brother #2

    \"Those are my principles. If you don’t like them, I have others.\" - Groucho Marx

  9. #9

    Join Date
    Jan 2003
    Location
    gone,
    Posts
    4,923
    Gallery
    My Gallery
    Models
    My Models
    Ratings
    My Feedback

    RE: what size drill bit for 1/4 20 tap?

    you'd be suprized how small a drill will work if tapping wood. You can get away with a 1/8 inch drill for a 1/4-20 tap in a pinch. Its a bit harder to tap out the hole... you have to back out and clear the chips a lot.

    One time, I actually drilled and tapped in one step. It worked but it was very slow.

    A good tap and die set will list different pilot drill sizes for different materials to get the best threads. When you are cutting threads in soft metal (brass and similar), part of the metal bulges in toward center, so you don't want quite as large a hole diameter as when doing steel or cast iron.

  10. #10

    Join Date
    Nov 2002
    Location
    Crete, IL
    Posts
    2,251
    Gallery
    My Gallery
    Models
    My Models
    Ratings
    My Feedback

    RE: what size drill bit for 1/4 20 tap?

    Most quality taps have the recommended drill size stamped right on them.
    The more you fly, the more you buy.

  11. #11

    Join Date
    Jan 2004
    Location
    portland, OR
    Posts
    81
    Gallery
    My Gallery
    Models
    My Models
    Ratings
    My Feedback

    RE: what size drill bit for 1/4 20 tap?

    ok ok. Who would have thunk that everyone would be soo interested in taps and drill sizes.

    I used the 3/16 and it worked like a charm. There are many times where I tell myself, its a model airplane, not the space shuttle so just make it work and save yourself some time and money.

    Thanks again,
    brian
    \"build em\' crash em\' and build em\' again

  12. #12

    Join Date
    Dec 2003
    Location
    haverhill, MA
    Posts
    1,511
    Gallery
    My Gallery
    Models
    My Models
    Ratings
    My Feedback

    RE: what size drill bit for 1/4 20 tap?

    ORIGINAL: themanimal

    There are many times where I tell myself, its a model airplane, not the space shuttle so just make it work and save yourself some time and money.

    Yeah but why not spend the time and do it right, then having to spend time again fixing what wasnt right the first time?
    \"We request that model aviation not be innocently sucked into a black hole of regulation...\"


Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
All times are GMT -6. The time now is 03:18 PM.

SEO by vBSEO 3.6.1 ©2011, Crawlability, Inc.