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.