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Need Help Flattening Chisels!!!

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Forum topic by jpthewoodworker posted 06-20-2018 01:51 PM 776 views 0 times favorited 27 replies Add to Favorites Watch
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jpthewoodworker

27 posts in 149 days


06-20-2018 01:51 PM

Topic tags/keywords: flattening chisels sharpening cbn lapping plate lapping

Hello everyone. I sure could use some help. I’m struggling with flattening some chisels and a plane iron and spokeshave iron.

I just purchased a 12 piece Narex premium chisel set. All but one chisel has as a belly in the back (plane/spokeshave has bellies too). I have spent HOURS on these chisels and most aren’t fully flattened. No kidding, I’ve probably got 15 hours of work in so far. It’s taking incredibly long. I can’t think of anything I’m doing wrong but i keep seeing people say it should only take about 20 min or so if there is a belly.

Here’s what I’m using:

180 grit CBN lapping plate
3 DMT Diamond plates: extra course 220 grit, fine 600 grit, extra fine 1200 grit
80 grit sandpaper on granite tile

My process:

1. Start on the 180 grit lapping plate and see where bellies/hollows are
2. Continue flattening on the CBN plate until i have the first 1/4 in or more from the tip with a scratch pattern all the way across the back near the edge.
3. Move through the rest of the grits and strop to get a mirror polish

The problem: It’s taking incredibly long. Is this just me or is this normal?

Things I’ve tried:

1. More pressure downward on plates
2. Less downward pressure (letting only the stones do the work)
3. Using 80 grit when I just can’t get flat. However, in the end, this doesn’t seem to work so well. I always use a permanent marker on the end. 80 grit takes it off pretty quick. But when I move to 180 grit plate, I remark the chisel with the permanent marker but the stone doesn’t even touch the marked area. Seems strange.
4. I’ve tried laying the chisel flat on my anvil and hitting the chisel with a hard plastic tip mallet (Thorex style mallet) in attempts to move the metal in the area of the hollows that need flattened. No luck for me with this method.
5. Lastly: I’ve even recently taken a sharpening course at a school. So, I thought I understood the techniques.

I’m at a loss. I sure would appreciate any help so that I can actually work wood with these things!

Thanks!


27 replies so far

View Sludgeguy's profile

Sludgeguy

36 posts in 295 days


#1 posted 06-20-2018 02:13 PM

It’s taking way too long.
I would call Narex.
Also, the entire back doesn’t need to be flat, only about 1/4” near the tip.
Good luck.

View Aj2's profile

Aj2

1787 posts in 1971 days


#2 posted 06-20-2018 02:13 PM

Just guessing here. When you advance to the finer grits the swarf moves around under the area your trying to cut flat.
Each time you move to the next grit it needs to be as flat as the previous.
I think you should get as good as you can and start using them.You might find they are good enough
Good luck

-- Aj

View bondogaposis's profile

bondogaposis

5049 posts in 2524 days


#3 posted 06-20-2018 02:15 PM

Change your process, flatten the backs with the 80 grit sandpaper. Only after the back is flat start moving through the other grits. It will go quickly once the initial flattening is done with the coarse grit.

-- Bondo Gaposis

View jpthewoodworker's profile

jpthewoodworker

27 posts in 149 days


#4 posted 06-20-2018 02:16 PM

@sludgeguy what would I ask them at Narex? For a new set? And yes, I’m only going for the 1/4” at the tip. Thanks for your advice.

View jpthewoodworker's profile

jpthewoodworker

27 posts in 149 days


#5 posted 06-20-2018 02:20 PM

@Aj2 thanks. Each time I move to a new grit, I make sure the scratch pattern from the previous grit disappears and in place there are finer scratch patterns. So, for example, on the 80 grit the scratches are deep. When I move to 180, I make sure the scratches from the 80 grit are gone before I move up to the 220 grit. So, in other words, I think I’m accomplishing what you are saying. I hope this makes sense. Thanks for the help!

View Andre's profile

Andre

2131 posts in 1979 days


#6 posted 06-20-2018 02:22 PM

On my Narex chisels the larger ones were real bad(of course) I use adhesive back 180 or 220 grit automotive sandpaper on either the jointer bed or a flat piece of granite for the initial flattening then 1000 W.S. followed by 8000 polish. (all blades hollow ground) A slight hollow not a problem as long it is not close to the cutting edge, I like to be at least an inch back, except for Japanese chisels which are usually only about 1/4”.
On the plane blades only worry about the first inch or so and on the backs the area were the chip breaker will sit.
Since switching to PM-11 irons I haven’t had to worry about flattening any plane blades!
Thinking back to when I did the Narex chisels (plus a set of Mortise) probably 4 to 6 hours total time each set, also had to square the Mortise chisel?
Did a set of Sweet hearts in about an hour.

-- Lifting one end of the plank.

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jpthewoodworker

27 posts in 149 days


#7 posted 06-20-2018 02:24 PM

@bondogaposis I have taken this approach as well. For some reason it isn’t working well for me. Here’s where I run into problems. After I have taken the back to the 80 grit, I have consistent directional scratches all the way across the back and it looks like I’m good to move on to the next grit. But, when I do, the next grit still shows hollows/bellies like it isn’t really flat. So what looks flat to me on the 80 grit doesn’t appear flat anymore when I move on to the 180 grit. I think what you recommend makes perfect sense but I can’t get it to work. It’s really throwing me for a loop!!! Thank you sir for your advice.

View Bill_Steele's profile

Bill_Steele

432 posts in 1904 days


#8 posted 06-20-2018 02:27 PM

I’m not an expert in this area, but it sounds like your approach is correct. I use several grits of DMT diamond stones to flatten and sharpen my chisels. Twenty minutes per chisel sound reasonable—an hour or more per chisel sounds excessive.

When you say “belly”—are you saying that the back of the chisel is convex? Some chisels have a concave area on the back—which I understand is intended to reduce the time/effort to flatten the back.

It’s possible that there is a manufacturing defect or quality issue with these chisels. Have you contacted the store where you bought them or the manufacturer?

I think the steel used in some brands or models of chisels is not as easy to grind away as others.

Is it possible that your lapping plate is not flat?

View jpthewoodworker's profile

jpthewoodworker

27 posts in 149 days


#9 posted 06-20-2018 02:28 PM

@Andre I don’t have issues with hollows. I love it when I have hollows (usually). The issue is that almost all of these have really bad bellies. So I have a ton more to abrade. Thanks for the input. It is helpful to know that I am not the only one with issues with Narex chisels. I hear a lot of folks saying they flatten them in 20 min or less. I’m way beyond that which is frustrating.

View jpthewoodworker's profile

jpthewoodworker

27 posts in 149 days


#10 posted 06-20-2018 02:31 PM

@Bill_Steele when I say belly I mean the back of the chisel is convex. I wish it were concave! It’s possible I got a bad batch of chisels when it comes to quality control. Maybe I should contact the seller or manufacturer. I think it is unlikely that the lapping plate is not flat. It is brand new and like a diamond plate in that they are pretty much guaranteed to be flat. Thank you sir!

View Aj2's profile

Aj2

1787 posts in 1971 days


#11 posted 06-20-2018 03:59 PM

What diamond plate are we taking about the plastic one?
Here’s a look at a lapping plate that’s very flat and made from bronze. But even this one can be tricky to bring a chisels back flat. It needs to be supported on a fairly flat surface to bear down on.
Does that make sense?
I don’t believe in the bad batch of chisel idea. Most likely your technique needs refining as your diamond plates are wearing in.
Keep at it

-- Aj

View jpthewoodworker's profile

jpthewoodworker

27 posts in 149 days


#12 posted 06-20-2018 04:21 PM

@Aj2 no, not a plastic diamond plate. I do have nice flat heavy duty plates. My actual lapping plate is a 3×8 180 grit CBN plate. Similar to diamonds but no fluid is used. It’s supposed to be that way. As far as my diamond plates go, I have 3×8 DMT plates. The CBN plate is new so its not worn down. The diamonds are worn a bit but not too much. My surface is a flat granite tile on top of my bench top. I agree with you that it might be my technique. Very possible. But knowing the mechanics of everything and having taken a specific class on methods to accomplish this, I am at a loss. I’ll keep trucking on for sure until I figure things out. Thanks for the advice!

View Andre's profile

Andre

2131 posts in 1979 days


#13 posted 06-20-2018 04:42 PM

Almost sounds like you may be rocking it slightly? This seems to happen when we get frustrated and attempt to hurry things up.

-- Lifting one end of the plank.

View jpthewoodworker's profile

jpthewoodworker

27 posts in 149 days


#14 posted 06-20-2018 04:49 PM

@Andre, it is possible. I’m not ruling anything out at this point. I have been very deliberate about trying to stay flat. But, yes, I agree. Quite possible.

View Woodknack's profile

Woodknack

12398 posts in 2553 days


#15 posted 06-20-2018 05:19 PM



Change your process, flatten the backs with the 80 grit sandpaper. Only after the back is flat start moving through the other grits. It will go quickly once the initial flattening is done with the coarse grit.

- bondogaposis

+1

Youre saying this doesn’t work but you’re quitting too soon.

-- Rick M, http://thewoodknack.blogspot.com/

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