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Flattening the back of a chisel

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Forum topic by Pyro posted 03-09-2020 03:55 PM 1044 views 0 times favorited 33 replies Add to Favorites Watch
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Pyro

91 posts in 1503 days


03-09-2020 03:55 PM

Hey guys,

I have a worksharp 3k. On a brand new chisel I start at 80 grit and work my way up. On a new chisel it just seems to take an eternity to establish a flat back. Does anyone have any tricks? I’m almost thinking of just sending new chisels into a pro. Thoughts?

Thank you


33 replies so far

View SMP's profile

SMP

5087 posts in 1248 days


#1 posted 03-09-2020 03:57 PM

How much are you trying to do? I usually just do an inch or so as that will last me a long time.

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Pyro

91 posts in 1503 days


#2 posted 03-09-2020 03:59 PM

Im doing as much of the back as I can fit on the machine. I was under the impression that a bench chisel should be flat since you end up doing some paring with it. Is that wrong?

View Wintergreen78's profile

Wintergreen78

96 posts in 1082 days


#3 posted 03-09-2020 04:25 PM

I just do the first inch of the back. That should go much, much, quicker than trying to do the whole thing. You can still pare fine with a chisel prepped like that. I bet you could actually do just fine with less, as long as you bevel really comes all the way to the back. The most important thing is not ended up with any back bevel. That is what hurts when you try to pare.

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shampeon

2167 posts in 3526 days


#4 posted 03-09-2020 04:27 PM

Bench chisels don’t need to have nearly as much of the back flattened as paring chisels. Just focus on the first inch or so. It’ll be flat enough for most general paring work. You’re just trying to get a polished reference surface on the back for sharpening.

As you found, it’s very hard to get the entire back of a chisel completely flat.

-- ian | "You can't stop what's coming. It ain't all waiting on you. That's vanity."

View controlfreak's profile

controlfreak

3226 posts in 944 days


#5 posted 03-09-2020 04:28 PM

I think the idea is other than deburring to never remove any material from the back of the chisel. Once someone removes or bevels that back to sharpen because there is less material to remove I consider it damaged goods because the only way to fix is to remove enough from the front to get back to the flat.

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HokieKen

20742 posts in 2481 days


#6 posted 03-09-2020 04:29 PM

You may want to get some coarser sandpaper, 36 and 60 git for example and work up from there instead of starting at 80. Personally, I’ve never had to go any coarser than 80 and I usually flatten the whole back for the reason you mention about paring. But, I can’t really say I think it’s a necessity, I just do it (ironically) because it’s so quick and easy on the WS :-) There’s also diamond lapidary discs available you could try for coarser grades.

-- I collect hobbies. There is no sense in limiting yourself (Don W) - - - - - - - - Kenny in SW VA

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WoodenDreams

1479 posts in 1253 days


#7 posted 03-09-2020 04:35 PM

+1 SMP, It’s not wrong to flatten full length of the back, but if the back edges are flat with the tip, the chisel will slide flat on a board to pear.

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PBWilson1970

220 posts in 736 days


#8 posted 03-09-2020 04:43 PM

Watch those sides of your chisel, especially if you’re flattening and polishing the entire back! I learned the hard way with some extremely nasty slices several years ago.

-- I love the smell of sawdust in the morning.

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bandit571

30516 posts in 4025 days


#9 posted 03-09-2020 05:00 PM

I just do about the first inch or so. Waste of time to do entire back…

Paul Sellers has a video (FREE!) about getting new chisels ready for work…..you might be able to pick up an idea or two there….

Flat back of a chisel? Take a look at the ura on the backs of Japanese chisels….

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

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Andre

5013 posts in 3148 days


#10 posted 03-09-2020 05:31 PM

What brand of Chisels? I have done lots vintage and complete set of Narex and Sweet hearts, I do as much of the backs as possible and yes some are bad, but even the Narex only took a few hours? I use 180 or 220 before going to Water Stones, 1000 then 8000.
Sure hope you are not working on Japanese chisels? :)

-- Lifting one end of the plank.

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bandit571

30516 posts in 4025 days


#11 posted 03-09-2020 05:46 PM

It generally only takes me about 10 minutes, at the most….per chisel, to get the back flat as needed…

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

View SMP's profile

SMP

5087 posts in 1248 days


#12 posted 03-09-2020 06:18 PM

I have a dedicated 1 1/4” paring chisel (old english one), for my bench chisels i just do the first inch-ish.

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Andre

5013 posts in 3148 days


#13 posted 03-09-2020 06:24 PM

LOL! Well you all have way to many chisels or just lazy? :) Really have a hard time comprehending the logic of them there work sharp thing a ma jigs?

-- Lifting one end of the plank.

View controlfreak's profile

controlfreak

3226 posts in 944 days


#14 posted 03-09-2020 06:28 PM

Maybe I am missing something here by assuming that someone altered the flatness of a chisel by improper sharpening? On decent chisels isn’t the back flat from day one? Other than needing to remove the burr when sharpening how does it get unflat?

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bandit571

30516 posts in 4025 days


#15 posted 03-09-2020 06:37 PM

Just took me 50 minutes to do 6 chisels….just now….and two needed a chip removed.

It is that time again…the week or two between projects….where I can clean and sharpen all the tools used….

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

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