This video is about making gears like the ones I use in my screw advance box joint jig.
But I used exactly the same kind of gears for my wooden router lift also.
Normally to have gears go at a right angle to each other
you need bevel gears.
But these gears are just flat gears
and surprisingly they work fairly well going at a right angle.
You'll need to create some sort of paper template for your gears.
You can create a paper template for the gears using my online gear template generator.
Or you can create the gear templates using my much more sophisticated
down loadable gear template generator program.
Or if you're using my screw advance box joint jig version 2 plans
You can just go into the plans. Click where it says templates.
Scroll down to the right size gear that you want.
Click on that. And then just print that out.
The next step is to cut out the template that you just printed
and glue it onto a piece of plywood.
You don't need to use a lot of glue, in fact the less glue you use the better.
Next we cut out the approximate shape of the circle around the gear template.
Now we use an awl to punch a hole in the center of the template.
As well as a hole between each pair of teeth that are on the gear.
Those holes help to guide the drive point of the 5/16 inch brad point drill
that we use to drill a hole around every pair of teeth around the gear.
The next thing to do is to set the table of your handsaw to about a 5 degree angle.
This gives the gear teeth a slight bevel, which makes them run much smoother.
You don't stricly have to do that
but the gears run a lot easier if you do.
A really useful thing to do is to add a piece of wood or plywood or whatever
and mount that so that your blade is actually running against it a little bit.
That will cut down the amount of tear-out that you’re gonna get
on the bottom of your gear as you cut them out.
With the handsaw table tilted to the right
we can now cut out the left side of every tooth.
That way the teeth will actually get a little bit narrow
as they get towards the bottom.
Next we need to tilt the handsaw table to the left.
Now on a lot of handsaws including mine
the table doesn't actually tilt to the left.
So what I'm doing is I'm putting a piece of wood
underneath the piece of plywood that I've got on top of the table.
Which will give me about a 5 degree left tilt.
So now with the table tilted left.
I can cut out the other half of the teeth.
Now with the holes that I drilled earlier
I don't actually have to fiddle around with cleaning up the bottom of the teeth
because the hole has already taken care of that cut.
And with the table set back straight
I'm just gonna give every tooth a bit of a trim
because I wasn't as careful when I cut out the initial circle.
Thanks to having a piece of plywood right up against the blade
My gear has hardly any tear-out on the bottom.
Now we're done with the paper template.
But before we get rid of it let's drill a hole in the middle.
Next I get rid of the template by
just sanding it off on the belt sander.
That's a bit messy though because it
actually kind of comes off in chunks so you might want to
just scrape it off with a chisel.
All right, so let's mount that new gear on the
box joint jig and see how it works.
Sometimes they jam a little bit.
But with this one I got a little lucky and there is
really no interference at all.
If the gears end up binding a little bit
then you can tweak them by just kind of
filing down the shape of the teeth a little bit.
This gear really didn't need any of that but
just showing to demonstrate.
You could also see how the teeth are a little bit narrow towards the camera.
This is from when I tilted the table on the handsaw.
The next thing to do is to add a little block for
where I'm gonna put the handle on it.
This gives the screw that I'm gonna use to mount the handle
a little bit of reinforcement.
One of the things that I always do with my gears is
to add a good coat of varnish.
The makes the gears slip a little bit easier on the jig
and more importantly
the varnish helps to bind the fibers of the teeth together
so that, hopefully that should cut down on wear.
Not that I've ever had any issues with wear
but just to be on the safe side.
For the handle I just use a piece of 5/8th inch dowel
with a hole drilled through it. I use a screw with a smooth shank.
But to get the smooth shank on the screw
it ends up being a screw that's too long.
But that's no problem. I can just cut that off with an angle grinder.
And grind a slight point back onto that screw.
I'm drilling a hole in the gear
that's just a little bit too small for that kind of screw
so I'm gonna get a really tight fit.
And now to mount the knob on the gear.
I put the screw all the way in then back it out a little bit.
Just to make sure that the knob has a little bit of play.
And I also want to make sure that
it doesn't stick out the back.
And now a final check to make sure that gear works.
I'm just putting on this gear mount
which has got this clever feature that I don't actually need to
attach the screw. Just tightening the other knob.
It locks secure in place.
And this gear seems to be running fairly well.
It's a bit loud but it does the job.