Replies

1. 
   UncleDunc | Jan 06, 2003 02:10am | #1

   The first table I found said 41/64, which sounds really tight when you're talking about lining up holes drilled in wood. 11/16 certainly doesn't seem oversize.

1. 
   4Lorn1 | Jan 06, 2003 04:02am | #2

   A lesson I learned in my short career as a machinist was that it depends not only on the nominal thread size but also the cut of the threads. Full. 2/3 and 3/4 threads are all standard and even among them there are variations among manufacturers. Additionally the rule is that the larger the nominal size the larger the variations between manufacturers and even runs by the same maker.

   While a standard figure will likely work the best method may be, IMHO, to grab a set if vernier calipers and measure the bolts you will be using. Average the measurement of three or four. As I understand it, I could have misunderstood this part, you want a fit that is drive tight but doable so maybe dropping a few thousandths would be advisable. I'm sure an experienced timber framer will contradict this but that is, the fit part, what I've read.

2. 
   FastEddie1 | Jan 06, 2003 04:21am | #3

   There's no line up problem if you clamp the two pieces in position before drilling, then insert the bolt before removing the clamp.

2. 
   pm22 | Jan 06, 2003 06:25am | #4

   My experience was drilling 1/2" holes with an auger bit and brace thru 6" timbers. Tight fit but it worked with accurate location.

   HOWEVER several years later, when the wood rotted, it was a bear to remove then [think sledgehammer]. So I sped up the operation with a 9/16" spade bit w/ extension. The moral of the story is to provide a modicum of clearance.

   Are you using notches to support your beams? Not to rely on the shear strength of the 5/8" bolts? Actually, the strength of the joint should come from the friction between the two pieces. In heavy timber framing, there are some things known as "ring connectors" which are to take the load. [But that is just book learning.}

   -PeterView Image

1. 
   4Lorn1 | Jan 06, 2003 06:41am | #5

   Love that cartoon in your sig line. Being an electrician I feel his pain, regularly. Where did you find it?

1. 
   pm22 | Jan 07, 2003 04:38am | #6

   This was elegantly purloined from a forum on OSHA. I found that from a thread on the Mike Holt forum. Actually, my entire purpose of writing the reply was to use the gif but actually it changes between two pictures - the other of which is the guy gets fried. But it didn't translate over. The inventor seems to be "Andy Shockmore".

   -Peter

   View Image

3. 
   mikemahan | Jan 07, 2003 05:56am | #7

   If you're satisfied that a 5/8" bolt (or bolts)  is satisfactory (which I wouldn't necessarily be if they're in shear), look at it this way.  Would it be stronger or weaker with a 3/4" bolt.  If it would be stronger, then it won't be substantially weaker with a 3/4" hole and a 5/8" bolt, will it?