Troule With A Plough Plane's Wedge

Re: Troule With A Plough Plane's Wedge

mikew


>Hi Tom,

Repeatedly forcing the wedge can blow out the cheeks, typically in front of the wedge's mortise, and often both sides.

Chances are it is an ill-fitting wedge. Let me know if you want some and I'll send a little German Beech your way for making a few wedges.

Also check that the iron is pretty straight. A bow along its length can prevent a wedge form seating well.

Take care, Mike

Re: Troule With A Plough Plane's Wedge

Larry Williams


>Something isn't matching up, Tom. It's hard to say what it may be. It could be the wedge doesn't match the angle required, the iron may not properly match the skate, the skate may be loose or several other things. The groove side of the iron will be curved, don't try to bend that straight. Several things have to be right to properly fit a plow plane iron. I always suspect those who think plow irons are easily interchangeable don't understand exactly what all is going on in seating a plow iron.

It's easy to underestimate the mechanical advantage a wedge gives you. You can easily apply hundreds of pounds of force to parts of a plane. I use wooden wedges to level some pretty heavy machines and you don't have to apply much force to the wedge to lift a corner of a 1,800 pound machine. The screw or rivet holding the skate under the iron is probably about 1/4" from the edge of a piece of wood around 5/8" thick. It doesn't take much force to distort the fastener or, worse, split the wood. If your skate and its mounting aren't damaged you can probably fix the fit of the wedge/iron. You may have to make a new wedge.

Re: Troule With A Plough Plane's Wedge

mikew


>Thanks, Larry. I looked at my plow irons and I never noticed that slight curve on the back. Learn something new everyday.

So is the slight spring to ensure a snug fit without undo pressure?

Take care, Mike

Re: Troule With A Plough Plane's Wedge

Larry Williams


>The curve is to provide a deeper groove for the skate. The groove, when properly matched to the skate, adds lateral stability to what would otherwise be a minimally supported iron. It acts much like a Morse taper, locking the iron. There's a lot going on in the seating of a plow iron, it's quite literally the most complex precision work in all of plane making complicated by interchangeable irons.

It may be the reason plow planes became such gaudy monstrosities. A plane maker could add any number of decorations and gimmicks with a relatively small increase in price. While they created show pieces, they lost the solid agility of the 18th Century plow. Using a small properly tuned 18th Century plow is a lot of fun, it's like driving a sports car.

My plow ****

mikew


>Here's the one I have begun using. Indeed, it is the only non-metal plow such as my small 043 I have. Works a treat on the larger work I do.

We'll see how lucky I am when irons come from abroad I bought as this one didn't have all the sizes I use. In theory the dimensions are the same...

Thanks, Larry.

Mike

One more thing

jim reed @ tallahassee


>I agree with others that the wedge is most likely not mating properly. Make a new one. Also remember to take light shavings (smaller than the thickness of paper). And do not plow through knots. Good luck.

Re: One more thing

Tom Colligan, Peoria


>Thanks Mike, Larry and Jim.

Larry, when making a new iron is it necessary to have it tapered (that compliments the opposing taper of the wedge)? I know that you do this, Larry, but for us normal characters is this step necessary? Thanks again.

Re: One more thing

Larry Williams


>Tom,

Others disagree but I think tapered irons contribute to the performance of wedge set planes. They make adjustment possible, resist backing out of the iron during use and limit the forces you have to apply to a plane. Plow plane irons that match traditional need to be both tapered and to gain the thickness the curve on the back of the iron provides. The most unpleasant tedious job we do in making planes is tapering irons. I wouldn't do it if I didn't think it's necessary.

Tapered irons

jim reed @ tallahassee


>It seems intuitive that a tapered iron would resist sneaking back up into the plane. I have not done any tests but I think it is so. I think the taper issue is more complex, however. A smith would probably start with a rod, flaten one end and beat the other end into a suitable thickness. It would be easier to taper than to process the entire bar to a uniform thickness. Maybe the taper was the result of an easier manufacturing process. I think the tapered iron chatters less because of its higher mass. Maybe these two items contributed to its ubiquity. I will agree that the availability of flat ground steel today certainly makes blademaking easier (except for tapering, which is quite a feat).