Fix warped plane blade?

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Forum topic by Scrape posted 05-31-2013 01:00 PM 2413 views 0 times favorited 11 replies Add to Favorites Watch
View Scrape's profile


21 posts in 2241 days

05-31-2013 01:00 PM

I recently acquired an old no. 6 plane in great shape except for one thing: a warped blade. Looked at from the edge, they blade is warped such that the chipbreaker only contacts the blade in the middle.

Is there a good way to un-warp this, or should I get a new blade?

11 replies so far

View Smitty_Cabinetshop's profile


13574 posts in 2042 days

#1 posted 05-31-2013 01:09 PM

Set it flat on your bench, and tap it with a hammer to straighten. An advantage of thinner irons. :-) Can’t hurt.

-- Don't anthropomorphize your handplanes. They hate it when you do that. -- OldTools Archive --

View bondogaposis's profile


3972 posts in 1774 days

#2 posted 05-31-2013 01:09 PM

Anything is possible, but if you want the best results w/ the least effort get a new blade.

-- Bondo Gaposis

View Brandon's profile


4151 posts in 2375 days

#3 posted 05-31-2013 01:16 PM

Yes, but the advantage of thicker irons is that they’re lest likely to bend on you in the first place. The only iron I’ve had this happen with for me, I hate to say it, Smitty, is a Stanley SW iron for a jack plane.

-- "hold fast to that which is good"

View bandit571's profile


14086 posts in 2107 days

#4 posted 05-31-2013 01:24 PM

Stick the iron in the oven @450. Allow about 20-30 minutes for it to warm up. Pliers to grab it, place warpped end in metal vise as fast as you can, and clamp it until cold. Check for warp.

Note: the ONLY warpped irons I have seen were from a couple Block planes, and it was due to the fact they were clamped down too hard for too long in the plane.

-- A Planer? I'M the planer, this is what I use

View Smitty_Cabinetshop's profile


13574 posts in 2042 days

#5 posted 05-31-2013 01:31 PM

Send it me, Brandon, and I’ll dispose of it for you….

-- Don't anthropomorphize your handplanes. They hate it when you do that. -- OldTools Archive --

View crank49's profile


3979 posts in 2394 days

#6 posted 05-31-2013 01:35 PM

I’d be afraid that heating to 450 for 20 minutes would anneal the blade somewhat.

Depends on the alloy and the type of heat treatment it had in manufacturing of course,
but this could lower the hardness in the worse case, or relieve some residual stress from quenching in the best case.

-- Michael: Hillary has a long list of accomplishments, though most DAs would refer to them as felonies.

View Don W's profile

Don W

17882 posts in 1991 days

#7 posted 05-31-2013 01:56 PM

I agree with Michael.

I’d put it in a vice, with 2 shims on the outside and a small block in the middle of the high side. Clamp it so its just a little (and by a little, maybe even start with none) over bend back. Check it. Keep going a little further over bend until its straight. The over bend is because it will usually spring back some, and you never really know how much, so its trial and error.

-- Master hand plane hoarder. -

View PurpLev's profile


8523 posts in 3072 days

#8 posted 05-31-2013 02:05 PM

+1 to Don’s suggestion.

I would only be heating the blade to intentionally anneal it – and only to reheat it later to harden it again , and then heat it once more to temper it. unless you know how to harden and temper, I would avoid the heating process all together.

-- ㊍ When in doubt - There is no doubt - Go the safer route.

View waho6o9's profile


7124 posts in 2000 days

#9 posted 05-31-2013 02:06 PM

2 3/8” (fits #4½, #5½, #6, #7) #BP238 $40.00 Buy Now
If you want to read up on IBC blades, here’s the info.

IBC blades can be had at Woodcraft locations and are named Pinnacle.
They seem to be on sale as well with a chip breaker, tough to beat that price.
They’re machined well and match like crazy.

View ZiCheng's profile


6 posts in 1628 days

#10 posted 07-20-2015 02:06 AM

I have just begun to learn about metalworking, and I think annealing would only occur if you are heating the steel to its critical temperature, which for high carbon steel would be around 1450 Fahrenheit. Heating the metal to 450 may temper it and soften it, but it shouldn’t soften it to the point that it would be considered annealed. I tempered a carving knife at around 550 Fahrenheit, to which point it should in theory be about 58 HRC, which is softer than plane irons typically are. Anyway, I have a warped plane iron too, so I may heat up my oven up to about 400 (which means in my case setting the dial to about 350), and hoping that if it is tempered, it would be tempered at around 60 HRC.

Here is a resource I used for my tempering temperatures:

View TheFridge's profile


5682 posts in 909 days

#11 posted 07-20-2015 02:15 AM

Had them same problem. I set on a chunk of softwood and used another 1×2 on the high spot and hit it with a hammer till it was straight enough to flatten the back. Didn’t take long if you choose to take that direction. It’s not that hard. So if you’re a cheap hoarding bastard like me, this isn’t a hard fix.

-- Shooting down the walls of heartache. Bang bang. I am. The warrior.

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