How long does plane blade last between touching up.

[Joe Hillmann]

How long can you use a hand plane before it gets dull and the blade needs to be touched up.

When I am working on smaller projects it seems like the blade only gets dull if I hit something with it or set it somewhere where it may get a bit of surface rust. But last night I started to re-smooth the top of my kitchen table. I sharpened the blade before I started then had to touch it up 2 times to do about 10 square feet of the table. Is it common to have to touch up the blade that often?

[Sam Takeuchi]

Yes. It depends on what you are planing, what kind of blade you are using, how fine you are honing your blade, how hard your material is, how you are planing, etc. There is no set rules, but in some cases, you would need to touch up a lot more than that. On the other hand, if your blade is soft, defective or otherwise less than optimal, that'll cause premature edge failure, too.

I don't know what you normally use your planes for, but if you almost never have to sharpen your blade unless you hit something hard, I have a feeling you are using pretty dull blade to begin with.

[Zach Dillinger]

Depends on the plane. I literally haven't sharpened my Mathieson jack plane iron it at least 3 months of nearly daily use, and it is still sharp enough to do what I need it to do. Granted, I use mostly walnut and pine, but still that's a long time.

On the flip side, I sharpen my smoothers, panel planes and jointers quite often. As soon as it starts to get more difficult to push the plane, or if surface quality degrades, I hone. So, its tough to say how long between sharpening simply because it varies greatly.

[David Weaver]

I probably sharpen a jack, fore or jointer plane in heavy use every 10 minutes of hard use, maybe a little less than that (in cherry or harder). The only thing I can suggest, other than experience will tell you when it's time to sharpen, is to make sure that it's not you getting tired and leaning on a metal bodied plane that's making it seem harder to plane. As you get tired and lean on the plane, it'll seem harder and harder to push. A scribble of paraffin on the sole of the plane will tell you if the plane is dull or if it's just you.

A couple of years ago, I offered to stroke test a couple of irons until they stopped cutting (big mistake, they last longer than you'd expect if you really push them to no longer cutting). I probably waxed the sole of the plane four times before it was actually the iron that was too dull to cut and not me just getting fatigued. For reference, I got about 1100 strokes on a 20 inch edge of hard maple before the best iron stopped cutting a 2 thousandth smoother shaving. The surface quality was kind of doggish at about 750 strokes, but you wouldn't care about that on a jack plane as long as it's still cutting.

I would never do that again, but it was instructive at the time and I got a couple of free irons.

One other side comment to file away, Bill Tindall and Steve Elliot (again, same guys who went after the chipbreaker data) provided a bunch of pictures to us on woodcentral describing how a plane iron wears, and one thing you can figure on is as the iron wears, the sharp edge will eventually be worn to a point above the lowest contacting area and instead of being a triangle, the edge will look a bit like a subtle half moon shape. The plane will require some downpressure for you to keep it cutting - that it would not have required when it was freshly sharp and still had relief/clearance behind the edge. I'd consider that pretty dull, but you can keep planing for a while if you provide a little bit of downpressure. If you put the plane on a surface, and the iron is not chipped and it will pull itself into a cut without downpressure, it's still sharp - there is still clearance left.

Once again, the fabulous kato and kawai study provided exact data on when that occurs (but I just don't remember when it was), because their intention was to describe what happens in a machine that would be used to cut wood, where an individual might not necessarily have the benefit of all of their senses telling them what's going on as the machine does the work.

http://bladetest.infillplane.com/html/wear_profiles.html

At any rate, if the iron is chipping, that's a problem, if you have no clearance after you sharpen, that's a problem. If it's you getting tired and you just need to wax the plane sole, no problem. If you're literally wearing the iron until it's dull, sharpening and then doing it again, that's great. Experience will tell you ultimately. I suspect as you gain some economy of planing (again from experience) you'll have no trouble planing a 10 square foot surface even if it has some minor tearout or marks from a coarser plane to remove. Until then, it's not unreasonable to sharpen once or twice to get the desired effect.

[Joe Hillmann]

David,

You seem to describe what was happening pretty well. With a freshly touched up blade (my idea of sharp isn't near what your idea of sharp is) the plane would cut beautifully with out requiring much down pressure. But after a few minutes I would have to put much more down pressure on the plane to get the blade to cut.

It was also an oak table that the finish had been worn of long before I got the table 10 years ago so all the pours in the wood were filled with who knows what could have made the blade dull much quicker.

Most of my planing before the table was either jointing the edges of boards or shooting the ends of them. So 2 or 3 months of that could be equal to 5 minutes of flattening a table top.

[David Weaver]

Finish could do anything, especially if there are pigments involved.

[Sam Takeuchi]

Could it be that pores have been filled with pumice? That wouldn't be too nice for the edge. Or your table material happens to have a lot of silica, or whatever. It could be any number of reasons.

[James Taglienti]

Ive used planes and scrapers to strip and refinish a lot of furniture made from the mid 1800s to the late 1990s and ive got to say that shellac, lacquer, polyurethane, hide glue, pva glue, just about any glues, pore fillers, and film finishes seem to dull a plane cutter faster than virgin wood - these things are chosen for toughness and durability- but old dried hide glue has got to take the cake its almost glasslike and can really trash a fragile steel edge.

[Dave Parkis]

What angle is the blade sharpened at? If you're using a 25 degree bevel for shooting and grain and edge grain on softer woods, I'd think you'd probably want a 30 degree bevel for surface planing of oak.