flattening chisel backs with lapping film

[bugbear]

The measure of flatness of a chisel's back is this: it must be flat enough to flex the burr back and forth between the beveled side. If it's not you can't easily remove the burr or you have to tip the chisel up when working the back - a de facto 'Ruler Trick' which I don't particularly care for.

That's a remarkably pragmatic definition of the elusive "flat enough"; I like it.

BugBear

 

[Jacob]

IF A NEW CHISEL NEEDS FLATTENING IT IS DEFECTIVE - SEND IT BACK
Sounds like you have defective chisel AND defective stone!

If you'll cover the quid and a bit postage, I'll send you one of the horrible green handled things. And then you can show/time how little work you need to get a new chisel it ready to work.

JH

Chisel arrived! Nice green handle. I haven't got a green one. Looks a good quid + postage worth. Before I fiddle with it - what would you say was wrong with it jhwb?
I notice faint scratchings which seem to translate as Huddersfield Technical College?

 

[Trafalgar]

The measure of flatness of a chisel's back is this: it must be flat enough to flex the burr back and forth between the beveled side. If it's not you can't easily remove the burr or you have to tip the chisel up when working the back - a de facto 'Ruler Trick' which I don't particularly care for.

That's a remarkably pragmatic definition of the elusive "flat enough"; I like it.

BugBear

I appreciate it! I've made the same statement on other forums after which a lynch mob was quickly formed by the membership.

Flat enough to move the burr back to the beveled side is pretty darned flat and certainly flat "enough."

Cheers,

CS

 

[GazPal]

The measure of flatness of a chisel's back is this: it must be flat enough to flex the burr back and forth between the beveled side. If it's not you can't easily remove the burr or you have to tip the chisel up when working the back - a de facto 'Ruler Trick' which I don't particularly care for.

That's a remarkably pragmatic definition of the elusive "flat enough"; I like it.

BugBear

I appreciate it! I've made the same statement on other forums after which a lynch mob was quickly formed by the membership.

Flat enough to move the burr back to the beveled side is pretty darned flat and certainly flat "enough."

Cheers,

CS

I'd say it's more than flat enough if a burr can be turned.

------------

I had a bit of an experience with someone taking the ruler trick to extremes on his newly bought set of chisels last summer. If ever it's possible to name it a ruler trick, as he'd double bevelled his chisels - for some unknown reason - at home before coming to "lend a hand" on some work I was doing on my new house. In spite of my managing to keep a straight face and calmly explaining the woes of what he'd done, he was adamant he was right and there was nothing wrong with the chisels. He was relegated to digging some fence post holes so he'd have a chance to think, but I'm still unsure whether or not it worked. Yep, my daughter's husband needs some work before he's straightened out and becomes a single primary bevel kinda guy. :lol:

 

[jhwbigley]

IF A NEW CHISEL NEEDS FLATTENING IT IS DEFECTIVE - SEND IT BACK
Sounds like you have defective chisel AND defective stone!

If you'll cover the quid and a bit postage, I'll send you one of the horrible green handled things. And then you can show/time how little work you need to get a new chisel it ready to work.

JH

Chisel arrived! Nice green handle. I haven't got a green one. Looks a good quid + postage worth. Before I fiddle with it - what would you say was wrong with it jhwb?
I notice faint scratchings which seem to translate as Huddersfield Technical College?

Yes, that's where they came from originally. They went to the trouble of engraving it, but never put into use. Then who ever got them from before me decided to try to take the name off? It does make me wonder what sort of person would think its a good idea to engrave the back of a chisel! :roll: Let us know how you get on.

JH

 

[GazPal]

Yes, that's where they came from originally. They went to the trouble of engraving it, but never put into use. Then who ever got them from before me decided to try to take the name off? It does make me wonder what sort of person would think its a good idea to engrave the back of a chisel! :roll: Let us know how you get on.

JH

The question is, if presented a kit from college would you like to have the college name emblazoned on most of your tools? Perhaps a reason for attempting to remove lettering, but methinks it more likely the tool was "borrowed on a long term" basis, or came as part of a batch of redundant stock rather than supplied to a college leaver, as most training facilities leave marking-up to the tool/toolkit's owner.

Engraving the blade (Face or back) tends to make it less likely for a potential thief to take an item, because such markings aren't easily removed. There's nothing wrong with marking tools in such a way, as long as the engraving is cleanly executed (No raised edges if stamped) and doesn't interfere with the hardened steel working surface or creation of a future cutting edge. I normally keep such engravings close to the bolster for this reason. Most old timers didn't engrave the blades on their tools because they lacked the tooling to do so and it was much easier to stamp timber, as well as avoid the risk of damaging cast iron.

Several of my handplanes were engraved with my name by a "then" girlfriend's mother who worked at G.E.C. as a parts & circuit board engraver. We unfortunately parted ways before I could have my chisels and saws engraved.

 

[bugbear]

Several of my handplanes were engraved with my name by a "then" girlfriend's mother who worked at G.E.C. as a parts & circuit board engraver. We unfortunately parted ways before I could have my chisels and saws engraved.

Engraved plane, you say?

http://www.facebook.com/photo.php?fbid= ... =1&theater

BugBear

 

[Modernist]

5000 views on back flattening. I'm speechless.

 

[GazPal]

Several of my handplanes were engraved with my name by a "then" girlfriend's mother who worked at G.E.C. as a parts & circuit board engraver. We unfortunately parted ways before I could have my chisels and saws engraved.

Engraved plane, you say?

http://www.facebook.com/photo.php?fbid= ... =1&theater

BugBear

Yes, but my were engraved in standard Arial font and only involved my first initial and surname. :lol: More decorative engraving would have nice to have and I often fancied copying gundog and scrollwork elements from the sidelock on a d/b shotgun I own, but had never gotten around to it due to work commitments. I think there's even less likelihood of it happening now, as my hands have suffered far too much damage since the onset of rheumatoid arthritis back in '03.

 

[GazPal]

5000 views on back flattening. I'm speechless.

I think your last post confirms you're not speechless. :lol:

 

[Jacob]

5000 views on back flattening. I'm speechless.

I think your last post confirms you're not speechless. :lol:

It ain't all over til the fat lady sings. And I've got the Bigley chisel challenge to face!
It's one of these here on ebay. Old stock but in new condition, never been sharpened - just the maker's 25º grind
I can see why a compulsive flattener wouldn't like it - the face is distinctly concave, with machine marks. So concave that if you attempt the semi-mythical paring cut with the face pressed tight down on a flat surface, it'll dive in slightly.
But I think it's perfect - the concave face means sharpening will take just a few seconds, simultaneously starting the flattening and removing the diving tendency. I'll take some snaps first.
A concave face is easy to sharpen and is self-flattening - every time it is turned over to remove the burr the flat area behind the edge gets extended slightly

 

[bugbear]

It's convex that is the work of the devil - concave (within reason) is a good starting point for flattening.

BugBear

 

[Modernist]

Slight concavity, standard practice by Ashley Isles

 

[Jacob]

Slight concavity, apparently standard practice with Axminster cheapos, and with various Stanley, Marples, Footprint bits n bobs over the years.
So what's all the flattening about then? They don't need it (after the first honing that is).

 

[DTR]

So concave that if you attempt the semi-mythical paring cut with the face pressed tight down on a flat surface, it'll dive in slightly.

I thought any bench chisel will do this, by virtue of the fact that a unhindered wedge-shaped blade will follow its own centre line; the centre line of a 30° bevel being 15° away from the axis of the chisel?

I hope that makes sense. A quick sketch probably would have been easier :?

 

[Jacob]

Surely if the chisel face is flat and pressed down onto a flat surface then the cutting edge won't engage anything? until the handle is lifted a touch. But a concave face will engage at the edge.

 

[DTR]

Surely if the chisel face is flat and pressed down onto a flat surface then the cutting edge won't engage anything? until the handle is lifted a touch. But a concave face will engage at the edge.

Ok, I see what you're saying now. I guess what I said was more of a generic statement rather than applicable to your specific scenario.

 

[GazPal]

Surely if the chisel face is flat and pressed down onto a flat surface then the cutting edge won't engage anything? until the handle is lifted a touch. But a concave face will engage at the edge.

Yes, but it would still slice slight undulations and obstructions clear of it's path. The handle would need to be raised for the edge to take a heavier bite and there'd be a need for more control.

Many seem to have different views concerning the definition of paring, but the first sentence - above - pretty much describes the act. The second sentence begins to define the act of carving, but can be applied to most actions carried out with chisels when used at low angles and as the angle of attack increases.

 

[bugbear]

Slight concavity, apparently standard practice with Axminster cheapos, and with various Stanley, Marples, Footprint bits n bobs over the years.

I take it "apparently standard practice" is extrapolated from a small sample?

BugBear

 

[Jacob]

Slight concavity, apparently standard practice with Axminster cheapos, and with various Stanley, Marples, Footprint bits n bobs over the years.

I take it "apparently standard practice" is extrapolated from a small sample?

BugBear

Well I've certainly noticed it often before and it makes good sense - easy to sharpen and self flattening. It was the first thing I noticed about the cheap Axminster set I bought some years back.
So perhaps chisel makers know more about it than we gave them credit for. Except for Lie Nelson who recommend a long-winded tedious flattening procedure! Somebody should tell them. :lol:
And I bet Narex are better than Matthew thinks and they also don't need flattening.

PS My sample size; perhaps a dozen chisels new from 4 or 5 different makers. And jhwbigley's green handled Marples example which I have yet to sharpen.