Low angle plane throat dimensions

[Marc Gélinas]

I'm currently in the process of designing a dovetailed infill low angle smoothing plane and was wondering if anyone had an inkling of the throat dimension (ahead of 3/16" iron) I should use.

[Mike Wenzloff]

Hi Marc,

It will depend on the angle of the bed. The lower the angle, the more open due to a longer projection.

Easiest way is to cut the throat small, position the iron on the bed and very judicioulsy pare the front open using floats down to the steel and then use fine files for the metal until you get the openness you desire.

Alternatively, you can just stuff the bed end and not stuff the front until the metal is filed enough and then cut the bun to fit the space. Cut it so it overhangs the front mouth edge and use floats or files to pare it flush to the metal.

Mike

[Marc Gélinas]

In an article by Christopher Schwarz, senior editor of Popular woodworking entitled "Building a Shepherd Smoother" he writes of wanting .005" clearence after putting in the blade and actually getting .008". What im wondering is, is there a sweet spot for smoothing planes that will allow for some flexibility without having to have some sort of throat adjustment mechanism.

[Mike Wenzloff]

Hi Marc,

Ideally, the mouth is tight to help control splitting ahead of the front of the mouth, which is the prime factor in causing tearout. A smoother with a really tight fixed-mouth is good for only one thing, and that's a final pass or two on a plank.

If you want more variability in use, you will need to have an adjustable mouth.

Mike

[Marc Gélinas]

Thanks a bunch to both of you! I'm going to complete a preliminary drawing and post it. I'll try to come up with a simple throat adjustment something or other that won't make making the plane more of a chore. Please be patient! I'll post both a .dwg file and .bmp or .jpg

[Michael Fross]

Thanks a bunch to both of you! I'm going to complete a preliminary drawing and post it. I'll try to come up with a simple throat adjustment something or other that won't make making the plane more of a chore. Please be patient! I'll post both a .dwg file and .bmp or .jpg
That sounds great Marc. I'm in the process of researching about building my first plane. Any pointers or drawings you have would be appreciated.

Michael

[Marc Gélinas]

Well here it is, a first draft in .dwg and .bmp formats. As you will see the design is preliminary and the "throat adjustment thingy" is a bit cumbersome looking, and probably will be a little annoying to use. However it is simple. I'm trying to avoid going to my local machine shop as much as i can with this project cause if I have half the work done at a shop I might as well buy one of these things. At any rate, i'd like to thank Mr Jim Yehle as you can surely see my plans are strongly influenced (a bit of copy paste work there) by his work on a Type 13 Infill Plane. The plans, bill of materials and insightfull and very helpful article are available at the following adress: WWW.xmission.com/~jry/ww/tools/a13/a13.html.

So please, all comments, suggestions, and criticism (of the constructive kind) are welcome

[Mario Brissette]

Hi Marc,

You project is amazing. Keep us informed ! :)

Thanks for the link also.

[Andrew Ault]

...there a sweet spot for smoothing planes that will allow for some flexibility without having to have some sort of throat adjustment mechanism.

Hi Marc,

Neat project! I've put together a cocobola Shepherd smoother. It was fun and very educational. I think a practical was to get the right throat size would be to make it with a zero clearance and then file it open to your satisfaction. You will need to do a bunch of filing anyway to get all of the surfaces coplanar.

You might consider extending the upwardly curving portion of the sides (next to the lever pivot) forward to increase the longitudinal rigidity of the plane that would otherwise be lost due to the throat opening. If you look at some other plane designs I think you will see that this design element is for this purpose. Conversely, you might want to lower the sides at the adjuster position to give your fingers some room to operate it.

I think the plane would be strong enough not to require the strengthening rods you show above the adjuster and iron. If you were to include one of these, would it not consist of a rod through a tube (where the tube would maintain the separation of the two sides while you peen rivet the inner rod).

I've just received three more Shepherd kits (thanks, Ben and Doug). When I get those done I want to make a miter plane and shooting board. I'd also like to make a chisel plane, though I hear the LN chisel plane's sweet siren call.

Again, great project! I hope it turns out just as you hope.

- Andy

[Marc Gélinas]

The zero clearence idea will certainly make my life a lot easier, i'll go that route for sure. As far as the sides and adjuster are concerned, i've been reworking the profile a little and toying with the idea of moving the handle forward and fishing the adjuster rod through the base of the handle. I'll post an up to date drawing soon.