if you define every new situation as 'every situation with different loads, differing tension conditions, differing species, differing piece sizes' - then yes, you may need to design a joint for each different scenario.
for most joinery, rules of thumb work just fine - that is most joinery that is not in tension, not holding down an open structure, not containing the spread of the roof, etc. etc. etc.
don's original post specified that you use the metal 'peg' table as a guide.
figure out your loading per joint
figure out what minimum size bolt will do the job in the species you are using.
use the bolt diameter you just calculated to fill in the 4d, 3d, etc. numbers.
replace the bolt with a peg of appropriate specie and diameter to do the job, at the dimensions you just calculated using the bolt diameter.
don - is that correct? or what you intended to convey?
then make sure that your tenon is properly sized to take the loading - so relish, thickness, etc.
double check against the material left over in the connecting member... just to be sure you don't snap a post or a beam.
you could develop a spreadsheet with a bunch of common values and pull downs for piece sizes / peg #s / etc. to work through 'common' situations.
and as to odd sizes - if you calc out that a .625" diameter oak peg will work, you could use 3/4" or 1". likewise if you calc 3/4" to work you can use 1", if that is all your peg jig will make.
Last edited by bmike; 12/02/09 02:02 AM.
