Iron Rebate Planes - A Design That Came And Went

Let's say your role in a shop required your traveling to the job site to fit and install fitments and suchlike. One plane that could do the work of two would be preferable when you had to carry your tools with you. Think also not in the modern rush sense of time but in the 19th or 18th century sense of time when it came to the energy and minutes spent adjusting such a plane. Not such a big deal after all.

It is even more puzzling that those plane irons are obviously not bedded at the same angle.

Konrad and I discussed this. We both think that the main reason was mechanical. If the front iron were at the same angle as the rear there would be that much less hand clearance and you would need more space between the irons to avoid interfering with the infill that surrounds the cutout for the second iron.

A fascinating post. I've never seen an iron shoulder plane in person, so this is quite an education for me.

The double-iron 1/2" plane is indeed a puzzle. Here's my question about that plane: are the wedges interchangeable? Or are they slightly different shapes? If the wedges are different shapes, then it should be obvious why there are two irons.

For all intents and purposes the irons and wedges are identical

Interesting. Here's what I had in mind there: assuming that the irons were not used at the same time, what if the wedges weren't interchangeable? You would have to have two wedges, but if you had only one iron, then one wedge would always be floating around loose. Two irons would solve that problem. But if they're interchangeable, then so much for that theory. I'm no authority at all, but I'm guessing that the design is just there to make it quicker to shift from one job to the other.

Woodworkers are good at devising complex solutions to very simple problems...

George Ellis shows an almost identical looking plane on p. 14 of "Modern Practical Joinery" c. 1902. On p. 15 he explains the purpose of the double iron rebate plane this way. "These are intended for cleaning up hardwood rebates quickly, the front iron cutting coarse, the rear one fine; either one can be used alone when required." Just found this book today on Google Books.

http://books.google.com/ebooks?id=GXZZAAAAQAAJ&dq=modern%20practical%20joinery&as_brr=5&source=webstore_bookcard

Thanks for pointing out The Ellis reference. I have the book but didn't know about the reference. But I think he is mistaken. In order to use one iron coarse and one fine you need to retract the coarse iron first. That makes no sense from a speed standpoint. That is if the speed gained from having two irons is really important you would do far better to have two planes.

It seems to me, and this is speculation, that having two different planes in one would be beneficial in a day where you have to haul your heavy tool chest to each job. Having a low angle and higher angle in one eliminates the need for two plane bodies and allows you to use it with the grain or cross/end grain with the low angle. Just a wild guess.