Setting up a Krenov-style jointer plane
I’m making a set of wooden planes in the Krenov style. Have finished a small lignum vitae and rosewood standard-pitch smoother (which I already find myself reaching for first) and a less successful shoulder plane in rosewood and Andaman padouk (in the style of a moulding plane, the wedge fills the throat – looks lovely, underperforms), and have just glued-up a 22 inch jointer in matai (a New Zealand native, aka black pine; looks a performs a bit like cherry) and English white oak (and taken delivery of a 2 5/8 Clifton iron with which to power it). Unlike traditional `Krenov’ makers, I’m using 10mm brass rod as the cross-pin, which I fit after gluing-up.
One of the problems with wooden tools of this style is their tendency to change shape when you drive in the wedge, right? You have to drive in the wedge, then true the sole to account for the effect of wedge pressure. A small issue with an 8 inch smoother, but potentially much more problematic with a 22 inch jointer, which needs to be sweet every time.
Here’s the question. If I position the cross-pin exactly half-way up the side of the plane, so that the pressure from the wedge is distributed through the centre-line of the plane, will it still change shape when I drive in the wedge? I think the answer is no, but I’m wondering what the experts think!
I’m also experimenting with a heavy iron (the Clifton is a beaut) and no chip-breaker – in effect, using a large wedge as the chipbreaker. It works fine with the smoother. Any thoughts on that?
Replies
Friend, if you're building your own wooden handplanes in the species you mentioned you ARE the expert.
Hi
The question you ask is an interesting one. If the "cheeks" either side of the plane blade slot were of constant and equal cross section and were either a parallelogram or a rectangle in elevation, then placing the pin on the centreline would probably result in little distortion. However presumeably the cheeks are in fact wedge shaped. This means that while placing the pin at the centreline might result in an even distribution of "stress" across the cheeks, that wouldn't necessarily result in no distortion. The problem is that the amount of stretch is dependent not only on the applied stress, but also on the length of the element being stretched (imagine the cheek is comprised of many thin strips or elements). In other words the top edge of the cheek will get longer than the bottom edge. I suspect that would unavoidably result in some degree of distortion in the sole of the plane (unless you reinforced the top edge with something much stiffer than wood such as a strip of brass/steel).
Ted
The geometry is really simple Ted - the cheeks are 3/8 inch (10mm) by 2 3/4 (70mm) boards glued to the sides of a 2 3/4 by 2 3/4 (70 by 70mm) core. The only difference down the length of the glued-up plane is the taper in the throat, which provides a whisker-thin mouth and opens up to allow the wedge and some clearance for shavings. In other words there's a bit less wood in the top half of the plane than the bottom half, if you see what I mean. Maybe I put the cross-pin a wee bit nearer the bottom to compensate.
Otherwise, I reckon my guess is right. Smack in the middle means no distortion!
Never made a plane, but consider this observation. Beyond the geometry you're taking about a chunk of what???
Why wood of course. Wood is a nautural and irregular material. If you were talking about a stress relieved hunk of cast iron or even plastic (anybody ever made a Delrin plane?) geometry would govern. Geometry counts, but there is still minute variation within that hunk of wood and those variations are going to vary with humidty and use no matter what you do. You just need to plane your plane.John O'Connell - JKO Handcrafted Woodworking
Life is tough. It's tougher if you're stupid - John Wayne
Funny you should say that John. Plastic. I saw a piece of what I thought was black perspex in a recycler's yard a couple of days ago and thought `hey, what about a shiny black perspex block plane!?' Polished brass screws and knobs! Talk about staunch.
So what's Delrin?
Another plastic thats really tough, non-brittle, and kind of slippery. I've seen it used in a number of things. I think the Spyderco Delica knives are made out of it. I had a gun rack in my Bronco that had Delrin 'blades' at the top and bottom that slipped between the window and the rubber molding to hold the rack in place. I was constantly amazed that it never broke loose with a couple of heavy rifles or shotguns in it even when I was using all 350 ponies and getting 3-4 feet of air!John O'Connell - JKO Handcrafted Woodworking
Life is tough. It's tougher if you're stupid - John Wayne
i started making planes before i went to study with krenov, continued while i was there, and still make them. i think if i were to look at all of them together, the crosspins, on average, would be in the middle. once the plane settles down, you really shouldn't have much movement problems. some people, when i was there, were obsessive about flattening, checking with starrett straightedges, etc. if i can get a little mystical here, the point of these planes is that they are sensitive and personal objects. after using it for a while, you will fell if there is something out of whack.... you'll know what the plane should do, and when it won't, the first place to check, if the iron is SHARP, is for a bump behind the throat. that doesn't mean, however, that you need to run to the sandpaper. just do some delicate work with ascraper and you should be okay, a slight hollow here is okay, too, slight being the key word.
like you, i have made a number of planes without a breaker. as long as the throat is tight, you will have now problems, in fact the shaving come fairly shooting out of the throat and are often staright and ribbon like, rather than curled. i have also made a number with brass crosspins, out of laziness. however, i do notice a different feel to those with a metal pin, and also like the way a wooden crosspin holds the iron better. on your next one, try it out! it takes maybe 15 minutes extra...
have fun...
if you ever have other questions about the krenov method, feel free to contact me... always happy to talk about planes
I appreciate FWW's efforts in setting up and maintaining this site and this post is not intended to do anything to show disrespect to FWW. However, if you want an answer to this question, post it here: http://www.wwforum.com/cgi-bin/forum_main/handtool.cgi
Both Steve Knight and Larry Williams post on the Badger Pond dark side (neanderknuckledragging) site and with other very experienced planemakers are very willing to give you the answer you want.
Bruce
Kiwi,
There's nothing wrong with this forum--I kinda like it here.
You should do your final flattening of the sole with the wedge and iron installed and the wedge set as you intend to use it. Any deformation caused by wedge pressure will then be taken care of. One of the things I've noticed is that a lot of woodworkers tend to set the wedge on a wooden plane with too much pressure. A properly fit wedge/iron combination should take only a light mallet tap when setting. Too much wedge pressure makes adjusting the depth of cut difficult.
Once one goes through with the short learning curve of setting the wedge and adjusting the depth of cut most people are amazed at the ease and accuracy of setting wooden planes. Minute adjustments made with ease on a wooden plane try my patience with both Bailey and Norris style adjusters.
Cap irons are the lease effective way to control tear out in hand planes. Cutting geometry, properly sharpened irons, small mouth opening and properly tuned planes are a lot more effective. Many of the problems with tuning and using planes come from ill fitting cantankerous cap irons and choking of a well sharpened and properly set plane is usually caused by them. I think they cause far more problems than they solve. I commonly advise people to back them off, away from the cutting edge, when they're trying to learn to use planes.
What I don't understand is why so many people search out super dense tropical hard woods for planes. Beech, the traditional plane wood, has better wear properties at the leading edge of the mouth than iron planes. For that matter, most woods do. Heat generated by the cutting and redirecting the shaving concentrates right on the face of the iron and on the leading edge of the mouth. Heat is a catalyst for wear in metal but has little effect on the wear properties of wood. Over the years I've been working with wooden planes, I've become convinced that most enlargement of the mouth on wooden planes comes from removing wear on the face of the iron when I hone it flat during sharpening. That's not to say that ham-fisted seasonal tuning hasn't had an effect on most old planes. Most of what people attribute to wear in wooden planes was actually caused by woodworkers removing way too much wood when tuning their planes.
One of the properties that helps a wooden plane is the ability to take on or loose moisture quickly. Dense tropical woods just react too slowly to seasonal humidity changes and the result is that they never quit moving. You end up tuning these way too often. One of the advantages of beech is its high volume of rays. Rays are oriented at right angles to normal wood cells and this results in the flat sawn surface of beech being about 40% ray ends. These rays are actually end grain and greatly aid in keeping the differential between core and surface moisture content low.
Thanks Larry, and the others. The job is done, and I've set the crosspin on the centre-line. Last thing last night I did a quick first-pass clean-up, cut a wedge, dropped-in the new (and untouched) Clifton iron and the plane produces shavings! Right out of the box - no truing, no tuning, no adjustment for wedge pressure, no work on the iron. Looks pretty staunch, too! Can't wait to tidy it up and tune it and do some scary-sharp work on the hardware.
The timbers for this plane are matai (which is probably not too far from English beech in behavior) and oak. I've not used matai before and have been impressed with it. Looks lovely, works nicely, seems to sit pretty still.
Why the fancy tropical hardwoods for the others? Well, Larry, mainly because I had the wood, and wanted to use it for me! I have some old beech table legs that I've carried from workshop to workshop for about 15 years as well, and I've been eying them for a couple of mid-sized planes using just-ordered Hock irons.
Gotta say I'm enjoying making and playing with these planes. I once had a long Stanley jointer, and could never get the sole true. It wasn't just being fussy either, the dam thing didn't perform, and I hated it! Already I'm in love with my matai wonder!
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