Donkey Ear Revisited: An Improvement???

[James Waldron]

A number of pretty good concepts were recently presented in "The Donkey Ear Experiment" http://www.sawmillcreek.org/showthread.php?242236-The-Donkey-Ear-Experiment and that got my brain spinning (not an unusual condition) and led me to a brilliant new concept that will amaze and impress you all (blush). I have now built a proof of concept structure with four goals in mind:



The work-piece needs to lie flat on a horizontal surface, not sticking up in the air on a ramp where it may not be entirely stable;
The cheek of the shooting plane must be supported so the user is not fighting gravity to hold the proper engagement with the work-piece;
The support of the sole of the plane must be kept in the proper angle to assure an accurate result; and
The planed face of the work-piece must attain a reproducible and consistent angle.


All my bench planes are light weight shop-built woodies. I wanted to eliminate that as a potential question mark, so I picked up an old, inexpensive Stanley Bailey 5 1/2. That has enough mass to power through pretty tough stuff. (I'll try the thing with one of my woodies, too, but first things first.) The 5 1/2 has a lot more clean-up to go, but I got the sole flat and polished, the blade sharp, square and straight (don't want camber on a shooting board), and did a bit of tuning on the chip breaker. At that point, the plane made very satisfactory lace shavings (1 mil or so). And it did thicker shavings just as well.

Now for the shooting board itself:

A substantial piece of left-over 3/4 inch plywood was available, so it's what I used. Pretty tatty stuff, but it's not going to be a tool, just a proof of concept, so no problem. It was a bit fiddley to work out the dimensions (and after my test drive, I have a bit more fiddling to do). And I learned that when I get more serious about a working tool, the order of steps may be important to attain the required precision and accuracy.

Maybe I should have been more concerned with precision and accuracy this time around. I ended up with a bit of twist in the shot face, maybe 1 to 1.5 degrees. At least I know where it came from (and why that order of steps may be important). And I had to make a small adjustment to one part that threw off the primary ramp height just enough to leave a tiny gap where the sole of the plane is not supported for it's full length. Works okay, but it's irritating.

The fence for the work-piece didn't hit dead square, so the work-piece sits just a touch, about 1 degree or so, out of square, and the resulting planed surface comes out tapered just a tiny amount. Adjusting the fence to square is well-known, so I skipped it on this build; I'll certainly take care of that the next time around.

Construction is pretty simple and easy to understand by inspection:

335465

And how the plane is supported is also pretty apparent:

335466

As you can see, the 5 1/2 is taking very nice, curly shavings, even on end grain. Those shavings were the result of my first test drive with a piece of BORG red oak. I started from the square edges and chamfered the piece on four edges:

335467

I feel I have attained all four of my specific goals. With this first "quick and dirty" assembly, I've learned enough to build another with accuracy and precision and be very satisfied with the effort.

For many, this structure will not be worth the bother. It's a lot more effort and a lot more detail than the simple ramp approach others have relied on for some time. On the other hand, for anyone who builds a lot of boxes or other work with miter joints .... I'm planning to make two, one at 45 degrees and another at 22.5 degrees for octagonal shapes.

[Jim Koepke]

Interesting design. I didn't understand the concept you explained before.

This looks like a cross between a shooting board and a miter jack.

jtk

[James Waldron]

In a sense, the "cross between a shooting board and a miter jack" concept is on point, although most versions of the miter jack I've seen are even more complex and demanding to build. So far, I've found no need for clamping a work-piece in my version, but it would be simple enough to add a toggle clamp if one wished.

If use as a "trimming guide" with a saw is wanted, as apparently was once common with a miter jack, it could be done but with considerable care. A clamp would probably be a greater value in that usage than in a shooting operation. I may give that a try with the current version; it can be a "sacrificial donkey" without great concern.

[Steve Voigt]

Looks good. Unless I'm missing something, I think it's a pretty old design, though. I recently saw a similar one on instagram:

https://www.instagram.com/p/BD3sz9QFrPa/?taken-by=berncarpenter

He mentioned that it was based on a design by Robert Wearing (so did someone in the earlier thread), so a little Googling took me to Alf's site:

http://www.cornishworkshop.co.uk/wwmitreshootingboard.html

She suggests elsewhere that Wearing may not have been the inventor, but just borrowed it from an earlier source. Anyway, it seems like a good design.

Edit: the article above is not by Wearing, but Alf mentions the Wearing connection in her index page here:
http://www.cornishworkshop.co.uk/shootingboards.html

[Jim Koepke]

Dang, just when you thought there was a new idea it turns out to be almost forgotten old school stuff.

What is that about great minds thinking alike?

Say Jim, with a design like shown in the first Cornish Workshop link in Steve's post it wouldn't be difficult to have two angles on one board.

jtk

[James Waldron]

Thanks, Steve. I enjoyed those links a lot. I never imagined that I was first - how rare that would have turned out to be in this technology as it has evolved over the centuries. I hadn't seen these, and having you do the research makes it easy. I've seen others that have some of the features, but not all. See, for example, Stephan Schrieber's blog, Blue Spruce Woodshop, http://bluesprucewoodshop.blogspot.com/2016/01/how-i-made-my-miter-shooting-board.html He relies on a groove to register the edge of the plane, but does not have the cheek ramp I have employed.

Looking at these, the berncarpenter link is the closest to mine, I think, as it has a ramp for the cheek rather than a shallow groove in the base to register the edge of the plane in the other cases. The cheek ramp is good, in my view, to assuring that the plane does not tilt out of registration and is biased into the proper orientation in use. I'm not sure that the groove in the base is adequate for those purposes.

Looking at Mr. Billsberry's implementation, I'm not sure I fully appreciate the apparent sliding attachment and the fact that the Vee surfaces do not close up. In the photo, it appears that the faces are as close as they are capable of and there is a substantial flat beneath the faces that the edge of the plane will ride in use. That seems to permit and unattractive degree of "wobble" of the plane in use and compels the user to force the plane into proper registration. In my opinion, that obviates one major benefit of the cheek ramp. I also don't see a benefit in the adjustability of the ramp; to make the gap even wider than that shown in the photo makes the cheek ramp increasingly useless for registration purposes and defeats the purpose of having it there.

In developing my design, I thought about leaving a gap between the two ramps to afford space for shavings to collect without interfering with the registration of the plan. The more I thought about it, the less I liked the idea. I wanted to try initially to close them up to a tignt Vee and see if the plane would push shavings out of the ramp in use. In fact, in the limited use so far, the shavings tend to stay in the plane to the end of the stroke and spill over the toe onto my bench. A few shavings stay on the plane, as shown in the photo in my initial post. The pile of shavings at the toe end of the Vee shown in the photos are untouched showing where they fell in use. No shavings were left on the ramp surfaces; very few even touched the ramp in the first place. (I suppose a dull blade creating dust instead of shavings might pose more of a problem, but I tend to sharpen before my planes create dust. Hopefully I will never learn if this sort of problem actually occurs.) I plan to keep an eye on the behavior os shavings over a longer period of use when I've build a more precise and accurate version that I can actually put into service in my working.

I suspect my thoughts will turn up somewhere. There are very few truly new features in tools and a number have been lost, particularly in the hand tool inventory, because of the decline of hand work over a too long sustained period.

Edit: And just saw Jim's post that showed up while I was writing the foregoing. I'm thinking on a multi-angle version. I haven't worked that out yet, but I'll keep looking at it.

[Steve Voigt]

Jim,

If I had a dollar for everything that I "invented" that had already been thought of…



Looking at Mr. Billsberry's implementation, I'm not sure I fully appreciate the apparent sliding attachment and the fact that the Vee surfaces do not close up. In the photo, it appears that the faces are as close as they are capable of and there is a substantial flat beneath the faces that the edge of the plane will ride in use. That seems to permit and unattractive degree of "wobble" of the plane in use and compels the user to force the plane into proper registration.


It looks to me like each of the ramps has a small vertical edge below the main angled surface, which would cause the edge of the plane to float above the flat you are referring to. It's unclear from the photo whether that actually works, but that's how I would make it. As I'm sure you know (you seem like a machinist/engineer type :)) a machinist's V block works the same way, and whenever I've made larger wooden V blocks for hand planing, I've done the same.

Good luck with your fixture and please post photos when done!

[Jim Koepke]

Edit: And just saw Jim's post that showed up while I was writing the foregoing. I'm thinking on a multi-angle version. I haven't worked that out yet, but I'll keep looking at it.

The difficult part for a two angled board would be to attach it to the bench surface without the holding method get in the way.

Recently I have found it beneficial to be able to use my shooting boards either right or left handed. This is especially true with mitering corners. One thought is to make the 'vise block' be at both ends and straddling the bench top. With my end vise my big board can be held using dogs set low enough to not interfere.

Another way would be to make various drop in angle sets.

jtk

[Patrick Chase]

Interesting design. I didn't understand the concept you explained before.

This looks like a cross between a shooting board and a miter jack.

jtk

That was exactly my reaction, too. Closer to a miter jack than to a shooting board though IMO.