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Bench plane cuts at corners of blade but not middle.

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Forum topic by gauntlet21 posted 02-04-2019 06:42 PM 1598 views 0 times favorited 14 replies Add to Favorites Watch
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gauntlet21

69 posts in 1010 days


02-04-2019 06:42 PM

Topic tags/keywords: hand plane troubleshooting bench plane

I’ve been hand planing for about 9 months now and occasionally when I have a relatively flat face on a board and the entire width of the bench plane is capable of cutting, the plane will continuously cut at both corners but not in the middle regardless of where I am on the board.

My setups are, new Lie-Nielsen #4 and #6 with original blades. The blades a recently sharpened and believe it or not, I have attempted Rob Cosman’s and Matt Estlea’s techniques to put a camber on the blades. I have the cap iron quite tight and the chip breaker is very close to the blade’s edge (1/32nd or so).

I have a couple theories but wanted to ask someone with more experience. Perhaps the cap iron is too tight and is causing the blade to “cup” ever so slightly in the middle?

I’d appreciate any other ideas.

Thanks


14 replies so far

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WayneC

14359 posts in 4897 days


#1 posted 02-04-2019 08:34 PM

Have you run a machinist’s square across the blade to ensure it is square and straight? Is your sharpening stone flat?

-- We must guard our enthusiasm as we would our life - James Krenov

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Smitty_Cabinetshop

16790 posts in 3418 days


#2 posted 02-04-2019 08:40 PM



I have attempted Rob Cosman s and Matt Estlea s techniques to put a camber on the blades.

Thanks

- gauntlet21

Check it with a straight edge, as Wayne suggests. It’s either cambered or it’s not, and it’s a key piece of the puzzle

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

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Robert

3781 posts in 2280 days


#3 posted 02-04-2019 08:42 PM

Sounds like plane tracks, which is caused by 1) sharp corners on the iron and/or 2) planing depth too low.

Given the frog support close to the mouth + the thickness of a LN iron cap iron pressure won’t cause bowing.

I would back off on the planing depth I’ll bet that’s what you’ve got.

-- Everything is a prototype thats why its one of a kind!!

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Sylvain

1050 posts in 3299 days


#4 posted 02-05-2019 03:40 PM

If there is no “relief angle”, the blade will skate on the wood.
What is the iron bevel angle at the very tip of the blade (in the middle if not the same across the width)?
interesting reading (read also answers to comments).

-- Sylvain, Brussels, Belgium, Europe - The more I learn, the more there is to learn

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gauntlet21

69 posts in 1010 days


#5 posted 02-15-2019 10:26 PM

I did check to see if my blade had a camber and it did not. Also, one error I believe I have made was in following the modified sharpening techniques of Rob Cosman when I took off my training wheels (Veritas MkII Honing Guide) and started sharpening freehand. Rob only uses 2 stones when resharpening his blades which already have a defined back, primary, and secondary bevel. I happen to have multiple sharpening stones and tend to touch my blades up using more than just two. In the sequence, I guess I found that as I move to a finer stone, I increase the secondary bevel ever so slightly. And as I resharpen, that secondary bevel gets larger and larger and larger. I’ve measured my secondary bevel to be about 35 degrees when I intended it to be closer to 25-28. My blade has just been skipping along the top of the workpiece. I’m in the process of flattening that secondary bevel back down to 25 degrees and will update once I’ve completed the resharpening. I’m also going to be sure that I get an actual (observable) camber on that blade. I’ve yet to buy a bench grinder so I’ll make good use of my 320 grit sharpening stone. Thanks for the feedback.

Dan

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Johnny7

500 posts in 1890 days


#6 posted 02-15-2019 10:53 PM


If there is no “relief angle”, the blade will skate on the wood.
What is the iron bevel angle at the very tip of the blade (in the middle if not the same across the width)?
interesting reading (read also answers to comments).

- Sylvain

Sylvain,

Great job of diagnosing the OP’s issue!
Apparently, that’s exactly what was wrong.

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Sylvain

1050 posts in 3299 days


#7 posted 02-17-2019 10:49 AM

Johnny7,
I hope it will solve the problem.
The hint is that if you start at the edge, the protruding iron will of course engage the board but not if you start in the middle.
Then one increase the depth which will only cause taking bigger chunk at the edge but with no improvement in the middle. Then one push hard downward, with the described results.
I have been there.

-- Sylvain, Brussels, Belgium, Europe - The more I learn, the more there is to learn

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Kpk0313

3 posts in 40 days


#8 posted 07-05-2020 01:27 AM

Hey Gauntlet,

Did you ever figure out the reason this was happening? I’m having the same problem. New No 4. Stones are flat. Blade appears to be flat. I am thinking It is my honing jig (inexpensive eclipse style), but not sure.

- Kevin

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Aj2

3165 posts in 2597 days


#9 posted 07-05-2020 03:24 AM



Hey Gauntlet,

Did you ever figure out the reason this was happening? I’m having the same problem. New No 4. Stones are flat. Blade appears to be flat. I am thinking It is my honing jig (inexpensive eclipse style), but not sure.

- Kevin

- Kpk0313

Have you tried holding a ruler up to the edge. I use the blade out of a starrett square to see how much camber is in my blade. A couple times I saw a hollow in my edge. I said to myself that’s odd. :)
Good Luck

-- Aj

View bandit571's profile

bandit571

26092 posts in 3483 days


#10 posted 07-05-2020 03:47 AM

Hmmm…usually means there is something under the iron….like a small chip about in the middle of the edge of the iron…holding it up in the middle….Chipbreaker is then forcing the corners down.

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

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Sanderguy777

245 posts in 2001 days


#11 posted 07-05-2020 05:44 AM

The other issue I could see doing this is if the sole of the plane is convex. That would mean the middle is sticking out more than the edges.

Not saying that IS the issue, just that it could be

-- Marc Spagnuolo (standing in front of clamp wall): I think I need a few more . Me (owner of at least 8 clamps):.....?

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Kpk0313

3 posts in 40 days


#12 posted 07-06-2020 03:29 AM

Here’s a sample cut that shows what I mean. And I tried to take a picture of the light reflecting off of the blade (different on edges than center).

AJ – I did hold a straightedge up to it. Hard to detect. I was troubleshooting and when sighting down the sole of the plane and while advancing the blade, I could see BOTH edges before the center. Very slight.

Bandit – Chipbreaker seems to be making solid contact without obstruction…

Sanderguy – Sole of the plane seems dead on (brand new LN) as far as I can tell. I just went and triple checked because that would make sense.

Full disclosure – I spent a day regrinding the primary bevel on sandpaper, and then noticing I was way off square and doing it again. Haha. That’s the reason for the multiple bevels in the picture. I’ve made a bit of a mess of the blade but has been a good learning experience. But – same result. Seems to be a hollow in the center!

My next thought is still to buy a nicer honing guide. Probably a good thing to get anyways but not sure if it’ll fix my problem!

Thanks guys for the responses.

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SMP

2233 posts in 705 days


#13 posted 07-06-2020 04:41 AM


Hey Gauntlet,

Did you ever figure out the reason this was happening? I’m having the same problem. New No 4. Stones are flat. Blade appears to be flat. I am thinking It is my honing jig (inexpensive eclipse style), but not sure.

- Kevin

- Kpk0313

That inexpensive exlipse clone has worse casting than we did in Jr High metal shop. And its common for them to bend the iron due to how bad it is. Simple fix though with a decent file and about an hour work. Ironically, Lie Nielsen has a good video on fixing it even though they sell a really high end honing jig:
https://m.youtube.com/watch?v=ojzzCXq5ook

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Kpk0313

3 posts in 40 days


#14 posted 07-06-2020 03:38 PM



That inexpensive exlipse clone has worse casting than we did in Jr High metal shop. And its common for them to bend the iron due to how bad it is. Simple fix though with a decent file and about an hour work. Ironically, Lie Nielsen has a good video on fixing it even though they sell a really high end honing jig:
https://m.youtube.com/watch?v=ojzzCXq5ook
- SMP

Thanks for the link! Will try it out!

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