Well my new split-top roubo workbench is nearly complete,
and this was one heck of a project.
I had a great opportunity to practice
some old skills and learn some new ones.
In fact, one of those new things I learned
is the concept of tapping holes in wood,
basically cutting threads so that we can use bolts
instead of using things like nails and screws.
There are some powerful applications for something
like this so let me show how we used it on
the bench and then we'll cut some together.
Pretty much all of the leg vice components from
Benchcrafted attach via bolts that go into threads.
It's really a cool thing if you think about it.
These are movable parts, things may break.
At some point we may need to replace the chop.
You may need to make an adjustment to the hardware.
It's good to be able to take it apart.
Here's another example.
This roller guide down here needs to adjust to hold
the parallel guide in just the right position,
so we need to make fine adjustments up and down.
Having threaded bolts here allows us to loosen things up,
make the adjustment, tighten it back down and
know that we're not really doing any damage
to the wood because it's in a thread.
Let's take a look at some traditional ways of using
hardware to hold wood pieces together and why
they might not be as good as a threaded hold.
Let's look at nails first. Nails are pretty much a brute
force way of holding things together.
A nail is driven into the wood,
splitting and compressing the fibers the whole way.
Over time, natural forces will cause the wood to
compress even further and eventually the two pieces will
come loose because the nail has nothing to grip on to.
One step up from a nail is a screw.
When you rotate the screw into the wood it pulls
itself in and essentially threads itself into the fibers.
The good thing about screws is they are removable,
but over the course of years if you loosen and
tighten one you wind up widening those threads.
You may even wind up destroying the threads,
which whole thing goes to poop at that point.
Now the star of our show, the threaded bolt.
Once the threads are cut into the wood you could
put this bolt in and out as many times as you need
to and it really doesn't do any damage to the wood,
because the bolts threads are sized perfectly to fit
nice and smooth into the threads that are cut into the wood.
This is perfect for applications where you may need
to loosen and tighten this thing over and over.
It's going to last much, much longer.
(groovy music)
All you need to make a threaded
hole is a drill bit and a tap.
These are basically a matched pair.
You want to make sure that the drill bit clears
most of the material out and leaves just enough
so that the tap can cut threads appropriately.
If you want, you can actually buy the tap and the bit
in a set so you know you have the perfect match pair,
but typically these are sized, you can look them up,
and you can make sure you get the
right tap set with the right bit.
And of course, you want to make sure that the tap,
the threads it winds up cutting,
are perfect for the bolt that you're going to use.
Because I was my hole to be nice and straight and
perfectly perpendicular to the surface I'm going
to use my drill press to do the initial drilling.
(drilling)
Now this is where the magic happens.
Typically you would take the tap and
put it into a special tap wrench.
It's basically a T-handled wrench
that gives you lots of leverage,
and you can twitch this guy down and
slowly but surely cut the threads.
I think we can do better than that.
If we take our time we can use a power drill and
get this done with quite a bit less elbow grease.
I'm just going to very carefully place the tapered
tip into the hole and very slowly start to turn.
Let the threads do the cutting,
you don't really have to push down.
You could speed up once you get started.
Obviously you want your drill on its slowest setting.
Once you get going ...
Let's pick up the speed a little bit.
Now we're pretty much at the capacity of the tap so
now we can reverse the direction and slowly pull it out.
You can't go too fast here,
if you go too fast you will strip everything
out and just have a nice hole, what you don't want.
You're backing out these treads as if
you were backing out an actual bolt.
Here we go. Let's give it a shot.
(squeaking)
Just as an example I just took a scrap piece
of wood and put a hole in it that's big
enough to take the bolt without catching.
This will serve as our example of something you might
want to connect when you're putting two pieces together.
Kind of like our roller brackets for the workbench.
One you get down to the bottom of the hole and your bolt
starts to make contact with your washers, you're going to
find this thing getting real tight, real fast.
That is going nowhere.
Check it out. Just one bolt,
these two pieces are together and this is no joke.
These things are really tight. I can't even move them.
Again, one bolt. Imagine if you had multiples,
you would have an incredibly secure fit,
and you would be able to loosen it and move this
piece if you needed to. Incredible possibilities.
Of course one alternative here would
be to use threaded inserts,
and I've used those in the past too.
The problem is they tend to come loose,
and not the threads themselves.
The threads themselves are made of metal.
You basically drill a hole and drive
the threaded insert into the wood.
It's the method that the insert is attached to
the wood that tends to come loose over time.
I don't really think those are the best solution either.
I think now that I know about this method I think
I'm going to use this a lot on jigs and fixtures,
and any project that I have a part that needs to
be loosened and tightened again, and I want to make
sure that it lasts for a good long time.
Here's the other thing that's great about this.
These taps are very cheap, only a couple bucks a piece.
And they're going to last forever because
you're not drilling into metal, you're just tapping wood.
You should have no problem with
these taps lasting for decades.
You'll probably pass them on to the next generation.
Spend a few bucks, get a couple taps.
Let me know what you think if
you include them in your project.
I'd like to thank Benchcrafted by the way,
because they introduced me to this entire technique.
I would have never thought of doing this in wood projects,
so I'd like to thank them for that.
By the way, if you're interested in this roubo workbench
build we're doing it right now in the guild.
Go to WoodWhispererGuild.com and
you can see what it's all about.
We have a plan and we're giving you just a ton,
a buttload, I like that phrase,
a buttload of video content for you to check out.
That's at WoodWhispererGuild.com.
Thanks for watching.