My Narex Paring Chisels Arent Straight (???)

[Frederick Skelly]

Before I sharpened them, I laid a high quality straight edge down the blade lengthwise (running down the back, from the handle to the bevel). In 4 out of 5 chisels (1 1/4, 1", 3/4" & 1/2") I see the same or similar thing:
1. The first 2" below the handle is perfectly straight - I cant see any light between the blade and the straight edge.
2. For the next few inches (moving toward the bevel) I see light. (Edit: I estimate the gap is between 1/64" and 1/32" wide but have not used a feeler gauge yet.)
3. Then the blade meets the straight edge again at the cutting edge.
It seems like the blade is very slightly "arched", for lack of a better word.

Ive read earlier posts that the blades are lacquered. I looked closely and dont think the lacquer is causing this "arch". And the arch was pretty evident when I tried to flatten the back - my stones would not polish an area about an inch wide, ALL THE WAY ACROSS the back (beginning about 1/2" back from the bevel). It wasnt concave - NONE of the blade would contact the stone in this area.

So I went ahead and sharpened 3 of them - the 3/4", 1/2" and 1/4". I was able to set the primary bevel to 25* and add a 2* secondary bevel and all 3 chisels slice pine end grain like they should. But Im thinking that paring chisels need to be straight AND flat to do their job - dont they?

Should I worry about this or not?

Thanks,
Fred

[Jim Koepke]

I think your wording is throwing me off. In particular:


I wasnt concave - NONE of the blade would contact the stone in this area.

Okay the typo would make it read, "It wasn't concave."

Can you post images?

So helpful in solving tool problems.

Another question is do you have a set of feeler gauges you can use to measure the gap where you see light in #2 above?

jtk

[Frederick Skelly]

Hi Jim,
Yes, you interpreted my typo correctly. Ill go edit the post.

I cant post any images tonight because my cable is broke. :( Im sorry.

I do have feeler gauges but couldnt juggle well enough to use them. (Sometimes I wish for a third arm, ya know?) But Im guessing that Im seeing a gap of between 1/64" and 1/32". Ill try to measure it after work tomorrow if something more quantitative helps though.

Thanks for giving me a hand.
Fred

[Jim Koepke]

But Im guessing that Im seeing a gap of between 1/64" and 1/32". Ill try to measure it after work tomorrow if something more quantitative helps though.


I would call the vendor in the morning if that is possible.

I do not recall any comments about chisels arriving bowed in any recent threads.

jtk

[Jim Belair]

Seems like a pretty minimal bow to me, although maybe too close to the bevel. How far up the blade are you attempting to flatten when you say that section wouldn't contact the stone? 2"? 6"?

I'm sure LV would take them back, sharpened or not, if you're not happy.

[Adam Cruea]

Personally, I'd much rather see this (a blade "bowed" and not contacting the stone behind the bevel) as opposed to the opposite.

I've only "flattened" my chisels back about 1/2" to an 1". There's really no need for further back, as the edge is at the end of the blade.

Just my two copper thingies.

[george wilson]

I wouldn't worry about a little convexity. Some long chisels are made that way. It helps the handle to clear the wood. What you don't want is concave blades. Then,the cutting edge can dive into the wood and you can't do anything about it.

[Chris Griggs]

As long as the cutting edge makes contact with the stone and allows you to remove the burr from and fully polish the back of the cutting edge you are fine. The little hollow behind it can actually make honing a little easier and really shouldn't have any impact on performance (YMMV)

EDIT (it would appear that George feels the opposite of me. This is stating the obvious but definitely listen to him not me. I always felt like concavity was of benefit becasue it makes sharpening easier. I think I'm mixed up about what is going on with the chisels anyway, but regardless of concavity or convexity, I think the most important thing is can you get them sharp. If yes, I say your fine)

[Hilton Ralphs]

I wouldn't worry about a little convexity. Some long chisels are made that way. It helps the handle to clear the wood. What you don't want is concave blades. Then,the cutting edge can dive into the wood and you can't do anything about it.

George, I'm sure the OP means his chisels are concave.

[george wilson]

Oh,I got up too early this morning. Send them back to LV. I caught words like "arched" and "it wasn't concave" in the OP's post. I think he could have been a little clearer.

[Mike Siemsen]

Fred,I like a chisel to be flat, but they really don't need to be flat all the way up. The reason chisel backs need to be flat, (and the stones you sharpen them on) is registration. It is easy to register the flat back of a chisel on to a flat stone. As long as you have a decent amount of flat on the pointy end you should be fine. I always use a very coarse diamond plate for flattening so i don't have to be at it too long. This flat will register on the wood as well. I alway soak in lacquer thinner before working on new chisels to get the lacquer off. Not all of them are lacquered. The big pain is when the blade is arched the other way and you can't get the bevel end to hit the stone.

[george wilson]

Mine are lacquered. Someone else said they were unable to soak theirs loose with lacquer thinner. Maybe it's not really conventional lacquer.

[dan sherman]

Mine are lacquered. Someone else said they were unable to soak theirs loose with lacquer thinner. Maybe it's not really conventional lacquer.


I got the lacquer off with a little soaking and some elbow grease. The thinner I used was old school not the new low voc stuff.

[george wilson]

Great! The tree huggers will be watering down WATER next.(Maybe tree huggers isn't the right word?) I like trees as well as anyone,but so many products have been ruined. You CAN'T idiot proof everything. And,maybe you shouldn't. Stuff that gets reduced to poor or useless sets me off.

I JUST noticed that spell check decided to change
products" to RODENTS!! I wish that feature could be made to work better. I have to proof read every word I type,and find ridiculous stuff like this!! WHAT could possibly cause products to be changed into rodents? Makes no sense.

[Frederick Skelly]

Thank you guys! Upon Mr. Koepke's advice, I measured the gap with feeler gauges. (Got my third arm by clamping the straight edge in my vise.) I was way off in last night's estimate - its nowhere near 1/64". The maximum I'm seeing on any chisel at any point is one place where it is 0.008". That's about 1/128th of an inch. Everywhere else it's less than 0.004 ". So I think this is non-problem based on manufacturing tolerances and what you all said above.

Thanks for guiding me to a solution. As always, i appreciate your help.
Fred

[george wilson]

Holding a straight edge to a polished surface always makes the error look worse. An air gap looks twice as wide because half of it is a reflection.

By the way,you can actually see light through a gap only .0001"(a tenth of a thou.) wide.

[Jim Koepke]

My original confusion may have led to the confusion of others.

Many of my chisels have a little belly. I don't thing I have any users with a concave back.

A gap being seen with a straight edge skews my mind toward concave.

Pictures always help to tell a story.

jtk

[Frederick Skelly]

Yes Sir, I sure found that out! Thanks again.
Fred

[Jim Koepke]

Found this video that says the concavity of the back is on purpose:

https://www.youtube.com/watch?v=nhO08NVbsPw#t=194

jtk