Auger Bit Extensions

This post is a bit long and is for those who have wondered how auger bit extensions work.

I'd been wanting to find an auger bit extension for a long time.  I finally hooked up with a guy from my tool collectors organization (PAST) and bought a Stanley #180, looking in perfect condition.  And he threw in another, very rusty one for good measure.  Total price: $10!  These tool collector guys are awesome! (He asked for $5 - I gave him $10.)

I believe the way these are advertised, they are said to "follow an 11/16" bit".  That means the end where you affix a regular auger bit will fit through an 11/16" hole.  So if you need to bore, say, a 5/8" hole that is greater in depth than your 5/8" auger bit is long, these extensions won't help you.  But if you want to bore a really deep 11/16" or 3/4" or greater diameter hole, this is the tool to help you.  For both of these extensions, the diameter of the large end is 11/16".

Diameter of the business end

In this post, I'll show how each works and what I did to clean them up.

Stanley #180 above, Craftsman below

The first one is a Stanley #180, in near perfect condition.  I think it's not that old, maybe from the '60s or '70s.

STANLEY
MADE IN U.S.A.
NO. 180 - 18 IN.

The tool is made up of three parts: the main shaft, a knurled and threaded sleeve, and the head into  which a regular auger bit is inserted.  I don't know if these are the proper names for these parts.

Yellow arrows are main shaft, red is the knurled sleeve
and green is the "head"

This photo shows the underside of the head (from previous photo).
The pen points to a key-way cut into the larger diameter part of the shaft.
Half-way up the head a key was punched that slides in the shaft key-way
and keeps the head from rotating on the shaft.

The portion of the shaft that is inside the head has a larger diameter than the majority of the shaft.  That larger diameter portion of the shaft has another purpose.  The knurled and threaded sleeve, which can slide most of the way up and down the shaft, butts up against that larger diameter so it can't slide further up.

Pen point shows the sleeve butted up against the larger portion of shaft

When the head is pulled down to the threaded sleeve, the sleeve can be rotated to engage the inside threads of the head, thus pulling the head towards the sleeve.

Red arrow points to the end of the shaft inside the head.
The sleeve's threads are just starting to engage the lower end of the head.

With the sleeve's threads fully engaged and pulling the head down,
the shaft protrudes further into the end of the head.
This forces the square shank of an auger bit up against the end of the head.

Now look inside the head so you can see the end of the shaft.  It accepts the square tapered shank of an auger bit.  When the sleeve is tightened, the head is pulled down and a bit is locked in place.

Note the square opening at the end of the shaft, seen inside the head.
Its orientation is important.

Here is an auger bit inserted.  Note its orientation.

When the sleeve is tightened, the shoulders of the bit's square, tapered shank
are forced against the inside shoulders of the head to lock the bit in place.

If the opening at the end of the shaft was not oriented as it is, the bit would not be held securely against the shoulders of the head.

The second bit extension works in a similar way, but with a different mechanism.  Here is my attempt to show the inscription on the shaft.  It was tough getting a decent picture of it.  These four pics are supposed to be shown side-by-side - hopefully that is how it is for your browser / phone screen.

   

It says: CRAFTSMAN on the top line and MADE IN U.S.A. A-I on the second line.  I'm not certain what the "A-I" part means, but it may be a code for whatever company made it for Sears.

This one was extremely rusty and totally locked up when I got it.  I oiled the moving parts several times and left it for a week.  When I got back to it, I wrapped a rag around the threaded sleeve and a wrench was able to loosen it.

Yellow arrow is the main shaft, red is the knurled sleeve
and green is the "head"

For this bit extension, the sleeve does not slide up and down the shaft.  It is fixed in position, but it can rotate so that its threads engage the inside threads of the head.  As it does, the head moves up or down the shaft.

In the above pic, note the L-shaped cutout in the head.  Through that cutout, you see the shaft.  At the far left of the cutout, you can see a pin that extends into the L from the shaft.  This pin limits the travel of the head.  But importantly, when the knurled sleeve is turned and the head has moved up, the pin locates at the right end of the L slot and allows the head to rotate 1/8 of a turn.

Sleeve threads fully engaged, head fully retracted, shaft showing inside.
Note how shaft's square opening is 1/8 turn off of head's square opening.

Here, sleeve threads are disengaged, pushing head up.
Now the pin is at the angle of the L

Here's a look down inside the head while it's pushed up.
Again, note how the square hole at end of shaft is angled from the head's square hole.

With head extended, turn the head 1/8 turn (pin slides in short arm of the L)
and the square holes will align.  This allows a bit's square tapered shank to be inserted.

After inserting a bit and rotating the head 1/8 turn, you tighten
the bit in the head using the threaded sleeve.  The offset square holes
of shaft and head force the corners of the bit's square tapered shank
against the inside shoulders of the head.

This allows a bit to be held firmly.  I've noticed that a little wiggling might be needed to get the bit into better alignment with the bit extender's shaft.  But when they're aligned, it really works great.

Here it is in use for a practice hole

As rusty as it was, this bit extender cleaned up nicely

This one took a fair amount of sanding to clean it up.  But it looks fine now and works perfectly.

So that's it on bit extensions.  I'm sure there are other designs out there with different mechanisms.  But at least now I know how these two do what they're supposed to do.

Making a Rounder Plane: Part 3

OK, so after gaining the experience of my first couple of experiments, I went into the following with a little more confidence.  I started with a block of poplar 9" long, 2" thick and 2 3/4" wide.  After later adding a 5/8" thick backer, the total thickness came out to be 2 5/8".

This rounder is for 5/8" dowels, so I bored a 5/8" hole through the thickness and then reamed the hole with a 6 degree tapered reamer.  The hole was centered along the length and width of the blank.  For the taper, I made sure not to enlarge the exit end of the hole.  Then I cut out the throat.

Hole reamed

Throat cut out at 30 degrees to a tangent at top of the circle.
The second cut here is at 90 degrees to the first.

You can see from the (roughly) concentric circles drawn on the large end that the tapering did not go as evenly as I'd hoped.  It's tough to get that right.  If I steer the reamer to have the entry hole centered in those circles, then I get the exit end being wonky.  I made pencil marks on the inside of the exit end to gauge progress and to see if I was removing more material on one side than the other.  Well, I was.  I  was getting to one side of the exit hole well before the other side got touched.

Oh well.  I kept going.  Next was to bed the iron.  I made sure the bed was flat and marked for screws.  After affixing the iron, I screwed a backer piece (with a 5/8" hole) to the tool and gave it a test drive.

Marking for screws to hold the iron

Iron in place and backer attached with screws

A first test.  The cut was very rough and I realized the iron was 
not flat on the bed.  (Backer not installed here)

I found that the iron I was using was not flat (not even close); it had a low spot on the top side center (that's the non-beveled side in this bevel down tool).  So I fashioned a cap iron out of a 1 3/8" washer.  This helped flatten it a lot, but was not perfect.

The "cap iron"

Here you can see gap between the iron and bed

Even with this gap, the tool cut pretty well and I produced some dowels with test runs.  I don't have any pictures to show it (though if you look carefully at later pics, you'll see), but I cut sort of a throat in the backer piece too.  I didn't go all the way to the hole - I wanted to have 360 degree support for dowels going through there.  Next pics are test cuts.

First stick cut fits nicely in a 5/8" test hole

Redwood, pine, maple and oak ready for rounding.
All were prepared by making octagonal, then removing facets
to make them slightly smaller than the entry hole. 

Starting the redwood stick

This is the entry side.  I think it helps with alignment to
have the rough stick just a bit smaller than the entry hole.

Maple produces some nice shavings

And this is a nice tight fit

Here's an oak dowel - the shavings are very different from the other woods

They all came out at 81/128".  Just a tiny nudge to the iron can dial them in.

And here's a key element to this that I mentioned in one of the earlier posts.  The iron needs to have it's exit side edge tapered back a little bit to get a smooth cut and a smooth dowel surface.

The pencil is pointing to the slightly rounded edge.  An even more gentle curve would be better.

Up to that point I had the backer piece screwed to the main body.  With the hole aligned very carefully, I glued the backer piece on and cut away the unneeded parts.  Then I cut away some extra material on the ends to make rough handles.  The bungee lathe was used to finesse the handles.

Cut away some material to make handles.
Here you can also see how I shaped the backer in the escapement area.

Shaping on the bungee lathe

Test cut with shaped handles - SO MUCH more comfortable

Put a size label on the exit hole backer

This thing performs great.  It turned out that the misalignment of the tapered hole didn't have much of an effect on the dowels.

But with that success, I decided to make one for 1/2" dowels.  I ran into problems with the tapered hole being more out of alignment with the backer hole.

The dowel is coming out not square to the tool

Here's the entry side.  I've gotta figure out a way to get the
tapered hole and the backer hole in the right alignment.

I'm going to remake the 1/2" rounder and try harder to get the holes to align.

Last thing here: I wanted to include this just to have it recorded somewhere.  When adjusting the bed, I found that the instructions Roy Underhill gave in "The Woodwright's Companion" needed a little tweaking.  He calls for a 30 degree bed angle, adjusted for the thickness of the iron.  But I found that an angle of more like 33 degrees was better.  Although it's possible that if I just made the bed as if the iron was another 1/16" thicker, it would have had the same effect.

And one more last thing.  I found that instead of having the hole centered in the length of the blank, having the hole left of center (for a bed that is angled to the right) by 1/2" would make the throat of the rounder be more centered in the body.  I'll make my next one that way.

Making a Rounder Plane: Part 2

In Part 1, I found that using a backer piece to guide the stick through the exit of a rounding tool can make a nice difference in getting a straight stick.  After rereading a section of Roy Underhill's book "The Woodwright's Companion" on rounder planes, I tried another.

This time I tried to make a tool with the straight (cylindrical) exit hole integral to the tool.  That is, bore a hole through the body of the tool, then taper the hole most of the way through, leaving the last 1/2-5/8" untapered.

This time I used a pipe deburring tool to make the taper.

And Roy suggests bedding the iron at 30 degrees to a tangent at the top of the circle

In this second experiment in making a rounder plane, I started with a 5/8" hole through a 2" thick piece of poplar.  I tapered the hole with a pipe deburring bit.  In the above picture, if you look closely down the tapered hole, you can just barely see that the far end of the hole is still cylindrical.

OK, this is weird and unsafe ...

Here's the exit end
(can you tell this chuck of poplar was formerly used as a chopping block)

For a number of reasons, I didn't have any success with this at all.  First, the iron was hanging about 1/2" over the front end of the tool and that's very unsafe.  Second, there were issues trying to incorporate the cylindrical section of the hole into the main block of the tool.  I really wanted the entire circumference of the exit hole to be supported - that is, I didn't want the top of the exit hole to be open as seen above.

The third thing was that this taper just seemed to be too great an angle.  It's about 30-35 degrees.  This makes it much tougher to get a workpiece started.  In theory it should work - it's just quite a lot tougher to work a piece of wood through it.  And it's very easy to get the first inch or so of dowel at an extreme angle to the workpiece we're using.  I wish I'd taken a picture of that one - it was bizarre!

After this experiment, I realized that I needed to make the tool with the taper going all the way through a 2" block of wood so that when the bed is cut the entire width of a spokeshave iron would be supported.  Also it would be much easier to incorporate a cylindrical section of hole by including a backing piece with a hole the exact target diameter that was glued or screwed to the exit side of the rounder plane.  As I'll write about in Part 3, that backing piece's hole needs to be in very good alignment with the central axis of the tapered hole.

Another thing that took some fiddling was that Roy suggests the 30 degree bed angle and to use the iron bevel down.  I had to adjust the bed a few times before it was deep enough for the iron to cut anything.

So experiment 2 was a failure.  But I finally got it right in experiment 3, which I'll write about next time.  Using a 6 degree tapered reamer for the hole, using a backer piece with the proper size hole, and getting the bed and iron adjusted just right make a huge difference.

Making a Rounder Plane: Part 1

This post is part 1 of a short series on making a rounder plane.

I've been experimenting with making a rounder plane, something I've wanted to do for quite a while.  I've made plenty of round sticks for various projects, typically using hand planes.  But there are times when I want more precision.  That is, I want more consistent cylindricity, er ... cylinderness, er ... cyl ... (oh, what the hay) roundness.

I have some homemade tapered tenon cutters from projects where a round tapered mortise receives a round tapered tenon.  I wrote about making these a few years ago.  The taper was created using a tapered reamer with 6 degree included angle.

This one, sans blade, tapers from 15/16" to 11/16"

Here's another, with iron affixed, with smaller diameter of 3/4"

You would think that if you keep working a tapered tenon through this cutter, when the stick gets to the small end of the tapered hole, it'll come out the other end a cylinder, and you'd be right.  But that cylinder is not anywhere near as nice as I would like.  The surface can be very rough and the stick might not come out straight.

There are some things you can do to help this along.  The first is to feather out the far end of the iron.  In the top-view picture below, the iron is bedded bevel up.  The arrow points to where the edge starts to angle back.  This makes a HUGE difference in the smoothness of the dowel being made.

Arrow points to where the edge starts feathering out

The second thing that helps is to have a backing piece with a hole the diameter you want your stick to be.  In the photo above, the red oak piece on the left is attached to the tapered tenon cutter with screws.  Its 3/4" hole is aligned with the conical hole in the main tool.

Here's the backing piece from a different angle

This backing piece helps form a straight stick.  In some other experiments, I created a round end on a stick, but the round end was at an angle to the rest of the stick.  Because the entrance hole to the tool is larger than the exit hole, it's easy for the stick to be aligned at an angle to the central axis of the tool.  

This entrance hole is nearly 1" diameter.

When the tool is used on a stick that is held in a vice, you can't see whether or not the stick is aligned with the central axis of the tool.  Without the backer piece, it would be especially easy to angle the beginning of the stick.

Rounding a stick that is held in a vice

But when the stick starts getting through the backer piece, it helps it stay in proper alignment.

Finally, it helps to start with a stick close to (but smaller than) the diameter of the entrance side of the tool.  This helps to keep the stick aligned with the conical axis so that you get a straight stick of consistent diameter.

Having figured out a few of these things, I made several 3/4" sticks from various woods.  They all came out at exactly 3/4" diameter (within 1/128" - the resolution of my digital caliper when in fractional inches mode).

A maple stick

Pine stick

An unknown hardwood stick
Yowzah!  And it measured 3/4" everywhere I tested it!

They all fit nice and snug in a 3/4" hole bored into a test piece.  I'm not thrilled with the surface finish that it leaves.  I can always scrape it smooth, but I'll have to be careful not to reduce the size of areas that fit into holes.

One thing to note.  When using the rounder with the backer piece, the resulting stick is a tight fit in the backer and it can make a dog-awful squeak in use.  Make sure to wax the inside of the holes to ease that a bit (and sometimes wax doesn't seem to help).

More on rounder planes coming soon.