Curved sole on bench plane?

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Forum topic by morty posted 10-11-2010 08:57 PM 2211 views 0 times favorited 9 replies Add to Favorites Watch
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9 posts in 2208 days

10-11-2010 08:57 PM


I have a new Buck Bros. bench plane and I was testing it out on a small piece of oak. After making several passes and getting a steady, even shaving across the entire piece, I took the wood to my table saw top to test its flatness. I was pretty surprised at how curved it was. I then retracted the blade on the plane and placed a straight edge across the sole, and noticed that it had a very slight convex curve from its heel to its toe. My understanding is that hand planes are to have a perfectly flat soles, and I assume the curve in my wood piece is due to the curve in the plane. Is this correct? And if so, should I try to flatten the plane? How would I do this? Would sanding it across pieces of silicon carbide sandpaper on the top of my table saw work? Thanks in advance!

9 replies so far

View PurpLev's profile


8523 posts in 3073 days

#1 posted 10-11-2010 09:04 PM

Ah…yes. a buck brothers plane….

yes. the sole needs to be flat. it’s ok if it has some low spots in certain areas, but as long as the toe-mouth-heel form a straight line it should perform ok.

best way to flatten it is with a sheet of sand paper (100 grit) over a flat thick granite slab. or use a belt sander to knock off the high spots, and then proceed with a sandpaper over a flat surface.

it WILL take elboy grease as there IS a LOT of material to remove (usually).

good luck.

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

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9 posts in 2208 days

#2 posted 10-11-2010 09:07 PM

My bad, I meant to say conCAVE curve on the sole. When I place a straight edge across it, I get about .006-.007 clearance under the middle using a feeler gauge.

Thanks for the replies, I guess I’ll have a go at flattening it. I’m thinking I could use a narrow piece of 3/4” wood to pinch one edge of a piece of sandpaper down in the miter slot on my table saw, and apply elbow grease.

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8523 posts in 3073 days

#3 posted 10-11-2010 09:32 PM

hmm, depending on where the low spot is – you probably don’t need to flatten it!

if the straight edge touches the front of the sole, the mouth openings, and the heel of the sole- don’t worry about the low spot, and don’t go about wasting your energy flatening the entire thing – it’s not necessary. BUT, if your mouth is not making contact with the straight edge, or one of the ends of the sole does not make contact with it – then flatten it just enough to get contact on those 4 points (toe, front of mouth, back of mouth, heel).

you may need to revisit planing technique to get the board flat. jointing a board is far easier than flattening it’s face. both require proper technique though.

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

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5839 posts in 3009 days

#4 posted 10-11-2010 09:55 PM

If it has a steel sole then try this.
Get yourself a sharpenning stone rectangular type for sharpenning woodworking chisels etc , and apply oil and elbow grease.
Then lock the plane in a wood vise and go over it many times.Keeping the movements very regular and on the plane ie don’t allow it to rise and fall keep it horizontal at all times when doing this. it will eventually flatten out perfectly.I saw this on a woodworking programme on tv where a guy brought an old plane back to new However if it is that bad send it back.Sometimes even new ones are not flat which they need to be .
Hope this helps Alistair

-- excuse my typing as I have a form of parkinsons disease

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9 posts in 2208 days

#5 posted 10-11-2010 10:07 PM

I spent a little time with it on the belt sander, and made a moderate improvement. The clearance is closer to .002 now. However, looking at the “non-shiny” places (where the belt made less contact) the area just before and after the mouth shows less sanding, i.e. the edges of mouth bow slightly away from the flat region of the sole, almost if the hole was “punched” from below. Maybe lightly hammering a piece of wood from above that is just larger than the mouth would press that area closer to the plane surface, and then I could re-sand.

View swirt's profile


2109 posts in 2396 days

#6 posted 10-11-2010 10:20 PM

Make sure as you flatten it, you put the frog in the plane as tightly as you would if you were using it. The frog is capable and often does warp the plane a bit on its own. So flattening without it in place can prove futile.

-- Galootish log blog,

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9 posts in 2208 days

#7 posted 10-11-2010 11:10 PM

Thanks again for all the suggestions. I’m starting to think my best course of action might be to invest in a better plane. (Apparently 30 bucks gets you a $30 plane.) I’m looking at the Stanley Bailey #04…

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446 posts in 2553 days

#8 posted 10-13-2010 12:42 AM

The Stanley planes need flattening too.

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456 posts in 2843 days

#9 posted 10-13-2010 01:16 AM

I think the plane flatness issue was covered well in previous comments. However, your planning technique is also important. Even with a flat plane it is possible to create a convex board surface (thinner at the ends, thicker in the middle). I am not saying that your technique is at fault, but it is something to be aware of. In fact, I can teach a lesson or two on how make a crooked board out of a flat one using a perfectly flat plane.

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