Sizing hole for screws

Reply

  #1  
Old 01-31-09, 05:48 PM
V
New Member
Thread Starter
Join Date: Aug 2006
Location: New Jersey
Posts: 311
Received 0 Votes on 0 Posts
Sizing hole for screws

I have a small safe that I'd like to hide in the attic. My plan is to put it under the insulation and bolt it down to the top plate of a wall. The safe is a quality model that came with an assortment of hardware, I would like to use some of the screws, they are small lag bolts with 3/8" heads. My micrometer says the outside diamter of the screw (threads) is 1/4", the shaft is smaller of course.

What size drill bit should I predrill the holes with? Is this screw small enough to sink in without drilling a hole, or should I drill to make sure the top plate does not crack?

Is there any simply formula to choosing the drill size for a particular screw? For example, should it be the diameter of the shaft? Somewhere between the thread diamter and the shft diameter?

Thanks!
 
Sponsored Links
  #2  
Old 02-01-09, 05:12 AM
Gunguy45's Avatar
Super Moderator
Join Date: Dec 2007
Location: USA
Posts: 21,113
Received 3 Votes on 3 Posts
You have it....diameter of the shaft is what most people use. Though it sometimes depends on type of wood, length and type of screw, etc...but dia of shaft is rule of thumb, gives max bite to the threads. Use soap or a candle rubbed on the threads to help it drive easier.
 
  #3  
Old 02-01-09, 06:11 AM
B
Member
Join Date: Oct 2008
Location: New England
Posts: 10,513
Received 37 Votes on 34 Posts
Hi, One thing you might think about, is the attic is a poor place to have your valuables in case of a fire. Most small safes have at best a limited time for which they will withstand intense heat. In terms of fire loss, the safest place in the house is the basement. Of course your gold stash will survive just about anywhere .

Bud
 
  #4  
Old 02-01-09, 06:36 AM
V
New Member
Thread Starter
Join Date: Aug 2006
Location: New Jersey
Posts: 311
Received 0 Votes on 0 Posts
It's an extra gun safe that I had laying around. I figured I'd put a last ditch handgun and some cash up there.

The economy is getting bad, you can't be too prepared for the upcoming crime increase.
 
  #5  
Old 02-01-09, 08:32 AM
B
Member
Join Date: Oct 2008
Location: New England
Posts: 10,513
Received 37 Votes on 34 Posts
Ya, born in Montana and used to think my parents and grand parents were a bit overly negative about our government. Then lived in NJ and had an episode of riots come right to my door step and realized you have to be able to take care of yourself. Suddenly my elders started sounding a whole lot smarter. Now I'm the elder and much better prepared.

Bud
 
Reply
Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description:
Your question will be posted in: