When drilling a hole for a simple dowel, more so, a post dowel, such as
cross support for a chair, do you drill the depth of the hole equal to the
length of the dowel or farther? I ask because of a chair I'm repairing. The
leg cross support are in an H shape (or I shape, if you prefer) with the
center cross inserted into each leg (side) support on left and right
attaching front leg to rear. I removed the center support from the broken
side supports and discovered the depth of the hole was about 3/8" deeper
than the actual length of the ends on the center support. It appears there
was a pile up of glue filling the gap. Therefore, I was simply curious if
this is the norm. Does it offer greater strength to have access glue filling
the gap? I can't see any difference since it'll be the same whether it's
wood or it's glue, though, IMO, the wood is stronger.
I like to drill dowel holes just deep enough that the parts fit
together, plus about an 1/8". That gives you just enough room for a
small bit of excess glue that gets pushed down from the sides.
With dowels, it is best to flute the sides in some manner to allow glue
to escape, otherwise you will get a piston effect and may not be able to
get the dowel to fully seat ... which may be why the hole you described
was so deep.
As Swingman said, the excess glue has to go somewhere.
If the dowels are fluted or spiraled, it can go out.
If the dowels are solid, it can go into the hole which is deeper than the
dowel is long or it can go out if the fit of the dowel allows it. If
neither of those it will either split the wood or be forced through the wood
structure of the dowel if the dowel is the type of wood that allows it. One
type of wood that does is ramin...kinda neat to see the glue oozing out of
the wood pores. Takes a lot of force to get it to do that though, hand
screws provide enough.
dadiOH, wrote the following at or about 1/3/2013 2:18 PM:
And if your dowels are neither fluted, spiraled or made of ramin (that's
noodles, right? How strong would that be?<g>), just grab a pair of
pliers and apply them to the dowel appropriately. Presto! Instant fluting!
On the ramin though, seriously, if it's that porous, how strong is it,
dadiOH? I realize that the question is largely academic in the context
of most doweled joints, but is it a very strong wood?
The only place I've ever seen it is on imported dowels but those are strong.
Other woods would ooze too...red oak would I think.
More on ramin:
For dowels or blind tenons, shoot 1/16" extra to give the
excess glue somewhere to go. Fluting the dowel with a
serrated pliers helps distribute the glue, as does also
chamfering the ends with a pencil sharpener -- the
ramped end forces the glue in between the dowel and
the hole, keeping the joint from being starved. You should
also apply glue to the hole, not the dowel. Applying glue
to the dowel insures that it'll be scraped off when you
drive the joint home.
HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.