Flattening Plane Irons

[Michael J Evans]

Not to hijack the thread.
But since I've begun using hand planes 6 months or so, everything I've read says you have to flatten and polish the back and that it's a once in a lifetime thing.

If that is the case then why have all 5 of my vintage planes been out of flat, and needed major time to being back to a polished edge? A couple of the woodies are real old and a couple of the Stanley early 1900's and a blue one.

Was the knowledge or equipment just not there a 100 years ago (or more) to flatten the back? And even if it was how come the the iron has went out of flat?

I'm not trying to go against the grain on this one and have flattened all of my irons. It's just bugged me everytime I spend an hour doing it. All I can wonder if why was this back good enough for the old craftsman.

[Warren Mickley]

Not to hijack the thread.
But since I've begun using hand planes 6 months or so, everything I've read says you have to flatten and polish the back and that it's a once in a lifetime thing.

If that is the case then why have all 5 of my vintage planes been out of flat, and needed major time to being back to a polished edge? A couple of the woodies are real old and a couple of the Stanley early 1900's and a blue one.

Was the knowledge or equipment just not there a 100 years ago (or more) to flatten the back? And even if it was how come the the iron has went out of flat?

I'm not trying to go against the grain on this one and have flattened all of my irons. It's just bugged me everytime I spend an hour doing it. All I can wonder if why was this back good enough for the old craftsman.

The "old craftsman" who knew his way about a plane was dying off in the 1840's not the 1940's. I used to talk to old craftsmen forty and fifty years ago; it wasn't hard to surpass their knowledge of planes. The plane you buy at the flea market was more likely purchased by home owner, handyman or carpenter than someone who wanted a fine surface on figured walnut.

We flatten the back so that we have a flat section near the edge for polishing the back side and finishing off the edge. We like enough flattened so that we get a good purchase on the stone for repeatability. Although when sharpening we do the bulk of abrasion on the bevel, the back needs some small amount of abrasion to take care of small scratches as they occur.

Because we abrade the back near the edge, it gradually gets out of flat with the rest of the iron around the slot. This is of no consequence. We just need it flat in the area near the edge.

[Steve H Graham]

The only thing that seems clear is that I have done it the hard way.

[Malcolm Schweizer]

When I finally get around to building it, I will post a thread, but I have designed and have all the parts for a 12" lapping wheel using a 1/4hp Baldor motor and a wheel from a disc sander with a diamond wheel mounted to it. I have to finish my never-ending workbench project and build a life-sized dinosaur for a children's museum first. Seriously.

[Steve H Graham]

I am confused. Shouldn't a children's museum display life-sized children?

[steven c newman]

IMAG0054.jpg
This iron from an Ohio Tool Co. 0-7.....was bowed badly in length...followed someone else's "advice" to use a vise to bend it straight...
snapped.jpg
Did NOT turn out nicely....had a friend with a good wire welder, and the shop tools needed, set it up, weld it back up, clean it up. I honed, flattened and have been using the repaired iron ever since. No, it is not a laminated iron, nor a tapered one..
IMAG0005.jpg
However, these two 0-35s use the laminated, and tapered irons.
IMAG0006.jpg
YMMV...

[Jim Koepke]

Gosh it has been eight years since posting "Fettling a Plane, From Junker to Jointer":

http://www.sawmillcreek.org/showthre...ker-to-Jointer

Post #28 in the thread has an image of a cap iron being worked on a Veritas Mk.11 Power Sharpening System:

Disk Sanding.jpg

This is also a great way to quickly work the back of a blade. Most of the time taken is letting the blade cool. In my days of fettling a bunch of planes it was quicker to work with a few at a time so one blade could be worked as others cooled.

Johnny Kleso built his own with instructions on his web site:

http://www.rexmill.com/sharpening/MKIII/MKIII.html

Besides this my best back flattening strategy is a four foot hunk of granite purchased from a monument maker (gravestone carver) with a long strip of abrasive adhered to it. Here it is without abrasive:

Granite on Horse.jpg

Dang it has been awhile since the shop was that clean.

jtk

[Chris Parks]

IMAG0054.jpg
This iron from an Ohio Tool Co. 0-7.....was bowed badly in length...followed someone else's "advice" to use a vise to bend it straight...
snapped.jpg
Did NOT turn out nicely....had a friend with a good wire welder, and the shop tools needed, set it up, weld it back up, clean it up. I honed, flattened and have been using the repaired iron ever since. No, it is not a laminated iron, nor a tapered one..
IMAG0005.jpg
However, these two 0-35s use the laminated, and tapered irons.
IMAG0006.jpg
YMMV...

Mine turned out OK. I have aslo used a Worksharp with diamond plates but when I go back to the stone from the WS it shows a different grind pattern which I find puzzling.