Tight mouths in wooden double iron planes.

[Steve Voigt]

The subtitled version of Kato/Kawai was on Wilbur Pan's blog. He had a recent glitch that temporarily disabled all his video links (he explains here). I imagine he'll have it up and running again in the near future.

[david charlesworth]

Thanks for the news.

Forgive me if this has already been said, but it seems to me that the best chance for shavings escaping from a narrow mouth, would be with small 80 degree c/b edge and a setting of 01 mm or 0.2 mm.

Having watched the Kawai- Kato video again, this condition seems to produce the straightest shavings. Has anyone tried this?

David Charlesworth

[Tom M King]

Here's the subtitled version: https://www.youtube.com/watch?v=56DpxEOpxz0

[Phil Mueller]

I think my question got lost somewhere in this thread. Could someone tell me the actual dimension of the mouth opening in the sole on a double iron wooden jointer? Not the opening with the iron in place, but the opening as seen from the sole. I know it will vary, but even a general point of reference would be helpful in my restoration project.
Thank you!

[Nicholas Lawrence]

Phil, on my 22" wooden plane (I am calling it a try plane), the mouth is about 7/16. I don't have any way of knowing if that is close to the original opening or not.

[Warren Mickley]

My double iron trying plane is 22 inches and has an opening just under 3/8 (without iron). The Seaton chest trying plane, 22 inches, and jointer, 28 inches, have openings about 1/4 inch. They have the old thin irons. The thickness of the iron makes a big difference. You might make a full scale drawing.

[steven c newman]

22" long Ohio Tool Works plane..
IMAG0102.jpg
Usually, those shavings come up and wrap around my wrist. Bit of a pain to stop and shake them off my arm...

IF you want, I can go to the shop and measure the mouth opening..

The one in the attached thumbnail is a No.81, also 22" long.

[Patrick Chase]

I usually run at ~0.2 mm, but seldom push the total face angle (bed angle + cap-iron face angle) past 100 deg. That's enough to get pretty straight shavings, and going higher seems to cause very localized trapping/jamming. Of course I might be doing something totally wrong...

IIRC Kato/Kawai used a bed angle of 40 deg (too lazy to re-watch) so they would have needed a slightly higher cap iron face angle than would a common-pitch plane.

[steven c newman]

Mouth opening between the wood and the edge of the blade
IMAG0054.jpg
According to my handy-dandy ruler 4mm
Shavings from jointing the edge grain of a 3/4" wide board.
.IMAG0055.jpg
Iron is a tapered, Thistle Brand Auburn Tool co.. With matching chipbreaker.
It will do all the things my two Stanley No.7c, T-9 will do. weighs a bit less, though..

[Phil Mueller]

Thank you both. Gives me a good range. It's a fairly thick iron, and at about 1/4" it's just not enough. Didn't want to keep opening it without some guidance.

[Steve Voigt]

Kees,
As an addendum to this thread: Tonight I finished up a smoother and decided to test a little. After I got the sole reasonably flat, I set the cap iron as close as I could get it, set the depth for a light cut (I would guess around .002"), and tested with feeler gauges. I got .012" for the mouth. There was no clogging, and I strongly suspect the mouth could have been finer; I think the .2 mm (.008") you mentioned at the beginning of the thread ought to be possible. The bed was 47.5°, the wear 85°, and the cap iron had a very small 50°secondary bevel (eyeballing it, about a fat 1/64"); otherwise it had a curved shape like the cap iron you showed. I think those are the key variables that make it work.

[Stewie Simpson]

Its doubtful tight mouths have much role of a role to play on double irons planes, apart from looking the part. Putting that aside, I have finished making a jig to rip the wedges down to 12* x 140mm. I also need to make up a solid template to cut the outer wedge abutment lines. The front edge of the cap iron also needs some further work.

Stewie;

[Kees Heiden]

Thanks a lot for the updates, both Steve and Stewie.

On my newest plane builds I have choosen a higher wear angle. They are now about 83 degrees for a 45 degree bedded plane. I'll see how tight I can get the mouth. I am not quite there yet in my proficiancy in plane making.

A picture of the smoother, subject of this thread, at work:

foto (4).JPG

[Kees Heiden]

Stewie, on closer examination of your picture I see you increased the height of the wear! Good call.

BTW, I make my wedges more like 9 degrees. I measured the wedges in all my old planes and they vary between 7 and 9 degrees.

[Stewie Simpson]

Due to a fault within photobucket I have resubmitted the photo's I posted.

Stewie;