hand plane chip breakers

[engineerone]

tidying up, i noticed an article about making your own infill plane, using brass. the guy had used a hock blade and chip breaker.

the chip breaker is flat front and back, so i was wondering if the only reason that mass produced chip breakers are curved is to give strength to a quite thin piece of material

is there any real evidence or knowledge of what shape a chip breaker should have?? since it needs to be flat at the place where they touch the blade, surely it does not necessarily need to be curved.

in the same way, is the reason the lever cap has a sort of spring on for instance record and stanley planes, economics or logic???
even my LN bevel up planes have a lever cap which is slightly curved what is the logic??

paul

[paulchapman]

In my view, the main reason for a cap iron (or chip breaker as you are calling it) on bevel-down planes, is to enable the blade to be adjusted, by the 'Y' lever engaging in the small slot in the cap iron. It needs to be in firm contact with the sharp end of the blade in order to prevent shavings getting trapped between the blade and the cap iron. In theory it doesn't need to be curved, but making it so probably ensures that it in fact touches the blade without any gaps.

I've come to the conclusion that cap irons don't actually do much in the way of chip breaking and no longer set mine too close to the edge of the blade. In fact, if you set them too close and have the mouth closed up to give a narrow opening, shavings will become jammed between the mouth and cap iron.

With thin blades, cap irons do help to make them stiffer. The best one in this respect is the Clifton two-piece (or Stay-Set) cap iron and I have them fitted to all my planes. The conventional bent ones are very poor in my view and tend to bend a thin blade.

Cheers

Paul

[gazza]

Aug 22, 2008 22:51:50 GMT paulchapman said:

I've come to the conclusion that cap irons don't actually do much in the way of chip breaking and no longer set mine too close to the edge of the blade. In fact, if you set them too close and have the mouth closed up to give a narrow opening, shavings will become jammed between the mouth and cap iron.

Paul

Very interesting Paul, the shavings getting jammed between mouth and cap iron, is a problem i suffer from.
I thought it was down to my poor technique.
I think i will try your suggestion of moving the cap iron back a bit to see if it helps. I was under the illusion that the cap iron should be as close to the end of the blade as 1/16", which isnt much, combined with the mouth set fairly tight as well.
Thanks for sharing your tip ,
Cheers,
Gazza.

[engineerone]

thanks again for another interesting viewpoint paul, since
we are all told to close up the chipbreaker/capiron to ensure that things are better, but i too will try your idea, since i too have
had some problems with some work, and this may well solve
that problem. i must say i agree about the thinner ones.

paul

[paulchapman]

Aug 22, 2008 23:14:23 GMT gazza said:

Very interesting Paul, the shavings getting jammed between mouth and cap iron, is a problem i suffer from.
I thought it was down to my poor technique.

Yes, if you look carefully in the mouth of the plane with the cap iron very close to the edge of the blade and the mouth closed up very narrow, you can see that there really isn't any room for the shavings to get through.

This used to baffle me because nearly everything I've read on the subject says set the cap iron as close as you can get it to the end of the blade when doing fine work. Like you, I was constantly unjamming shavings from the plane. As soon as I moved the cap iron back a bit, all the problems went away and I was able to get silky smooth shavings with no jam-ups

Cheers

Paul

[mrgrimsdale]

chip breakers are curved is to give strength to a quite thin piece of material

As I understand it they are curved in order to transmit pressure on to the face of the plane blade as near to the cutting edge as possible, in order to keep the back pressed down on to the frog, or mouth back, to avoid chatter and keep it solid.
It's effectively a spring, and itself pressed down again by the lever cap (or wedge on a woody).
It doubles up as a "chip breaker".
You could get the same effect with a single thick plane iron but the back would have to be slightly hollow to get the cutting edge firmly held down, and you'd need a chip breaking "bulge" machining on to the face behind the edge.
So thin blade + cap iron + lever cap is a more practical option.
But planes with high angle of blade, approach becoming "scraper" and the chip breaking is done by the face itself.

cheers
Jacob

[engineerone]

interesting theory, which we have all been told, jacob, but in a practical sense i must confess my feeling that it is a way that the manufacturers of cheaper planes can save pennies does not go away.

by introducing a spring at the base of the blade, you are basically causing the blade to bow and not stay flat against the frog, which i would suggest is why you get chatter with thinner blades. more importantly it means that the retainer needs a really strong spring at the rear to hold the cap iron in.

whilst i do not agree with the reality of the idea, i can see it as a relatively plausible reason.

paul

[mrgrimsdale]

Aug 24, 2008 10:34:25 GMT engineerone said:

interesting theory, which we have all been told, jacob, but in a practical sense i must confess my feeling that it is a way that the manufacturers of cheaper planes can save pennies does not go away.

Not a theory Paul, it's a fact!

by introducing a spring at the base of the blade, you are basically causing the blade to bow and not stay flat against the frog,

Other way around - the spring holds it tighter against the frog!

which i would suggest is why you get chatter with thinner blades. more importantly it means that the retainer needs a really strong spring at the rear to hold the cap iron in.

whilst i do not agree with the reality of the idea, i can see it as a relatively plausible reason.

Phew, glad you can see it!

paul

Anyway what on earth is wrong with making things more cheaply if they work as well? A thin blade, held down by cap and lever, will cut just as well, sharpen more easily, and last just as long , as a thicker one

cheers
Jacob

[engineerone]

cmon jacob you said "as i understand" now you are saying it is a fact, can't have it both ways.

i have just taken three of my planes apart to move the chip breakers back a little, and notice that my LV have a curved chip breaker, whilst the clifton has a much smaller curve with its
removeable front section. but the thick and flat chipbreaker i saw was a Hock one, and you can be sure mr hock would have done similar investigation to each and every part.

whilst i agree that it is always a reasonable position to make your products more economically, the continual search for cheapness will eventually create problems.

as for the thin blades i cannot agree with you about them being as capable as thicker blades. many have experimented with various changes, and just moving to a thicker blade has more impact on chatter than anything else.

if you look carefully at the bending moments it is confusing.

the chip breaker and cap are fixed by a screw through to the frog, but the tension of the blade is set by the adjuster screw
at the front, and the spring or as in the case of LV, the set
screw at the end. what you therefore have is the pivot point setting determining how and where the pressure points are, and certainly a screw at the rear is able to provide more pressure than the spring lever used on for instance clifton, record and stanley.

since the front of the blade is unsupported by the frog, the likelihood is that if the cap iron is too far to ward the front of the blade, it will tend to bend the blade back toward the rear of the plane, particularly if the blade is thin, and every time the wood breaks, then the blade will kind of spring back, which motion has been mentioned by others before.

paul

[engineerone]

well have taken paul chapman's advice, i have moved the chipbreakers back a little on 3 of my planes, lv 41/2 and 6 plus clifton 5, and it is true they work better in my hands. so thanks for that. actually it has enable me to feel happier with the clifton than for some time, somehow i had not "got them" now i understand better what people see.

now must try this on the no 9 LN mitre plane to see whether it has any effect there too.

so if nothing else this thread has enabled my hand planing to move up a gear. ;D

paul

[engineerone]

course i forgot the no 9 was a bevel up plane

anyway tried the three planes out on 3 different types of wood,
pine. oak and cedar. worked a treat on them all. so again thanks paul.

so now i need to see if i can find some of those plastic covered dogs to allow me to plane thinner stock more safely for the plane, particularly its sole

and also has anyone got the link to the slick plastic that axminster sell??? particularly the rolls.

paul

[Alf]

Aug 24, 2008 16:02:10 GMT engineerone said:

so now i need to see if i can find some of those plastic covered dogs

Pish tush - wooden dogs.

[engineerone]

so presumably alf you have some data on your site

any links or where else do i find out about them/

paul

[Alf]

Oh dear; how have we come to this situation where everyone believes we have to over-think this stuff? It's not hard, really it isn't. Square hole - make a length of scrap to fit. Round hole - bit of dowel. If they slip, stick a ball catch in the side and you're done. There are variations on the theme, but that's the gist.

[mrgrimsdale]

Aug 24, 2008 16:02:10 GMT engineerone said:

snip
so now i need to see if i can find some of those plastic covered dogs to allow me to plane thinner stock more safely for the plane, particularly its sole

The best planing stop for thin stock imho is a few nails or screws in the bench top. You set them below the surface of the stock and the edges of the heads will dig in to the sides of the workpiece, and hold it more firmly in place than a straight stop.
2 screws at the far end, 2 more along the far side.
Not favoured by many as 1. not having to buy anything takes the fun out of it, and 2. you make holes in your beautiful highly polished workbench top. ;D ;D
If 2 is the prob I'd suggest having a second bench for actual woodwork

cheers
Jacob

[paulchapman]

Another way to plane small pieces, engineerone, is to use a planing board. A piece of MDF would do. You could rout some grooves in it, in which to hold the workpiece; fit dowels in it to act as stops; or whatever. Then there's always double-sided tape........ Lots of options depending on the size/shape/thickness/length of the piece.

Cheers

Paul

[engineerone]

having seen the idea about plastic stops in :-[one of the american mags i just thought i'd ask.

then alf talks wood, and like a sensible person i was sure she had devised another item like her level for plough planes
i thought dowels were much too easy ;D

as for jacob's idea, in joinery i can see that, but surely if you have cut your piece to length, then having nails which bite into the sides and an end mean it is more difficult to make it look good on the visible portions.

as for your idea paul, i kind of have that, but since i have moved the bench i have more space, but less convenience, so i am looking for sensible ideas, and your planing board offers many ideas, but of course one worries about the length to make it

in many cases since the bits are no longer than 600 mm the planing board does not become too long, and can of course incorporate things like wedges etc. but what do you do with really long bits???

being kind of lazy, i am thinking of a combination product/jig which would allow me to use it as an end grain ie shooting board, plus edge , plus faces, and also combine the useful donkey's ear. so i am looking at a modification of walt's item that you posted some time ago.

again though thanks for the differing views.

paul

[lwilliams]

Aug 24, 2008 10:34:25 GMT engineerone said:

....i must confess my feeling that it is a way that the manufacturers of cheaper planes can save pennies does not go away....

paul

I believe historical evidence strongly points to the cap iron itself being a cost saving "innovation." I think its introduction was the first strong evidence of compromises made in hand planes as they transitioned from a locally produced artisan product to a mass produced commodity type of product.

As the physical distance between the maker and the end user grew, costs other than production costs start to heavily weigh on the final price. In the move toward the retail type of commodity the price of packaging, shipping, warehousing, displaying and marketing of a product has to be included in the final price. These costs are involved three times, for the maker, distributer and the retailer. It starts adding up quickly.

Before the cap iron became all that was available bench planes could commonly be purchased in the four traditional pitches -- common, York, middle and half. The cap iron was marketed as a big improvement that takes care of tear-out and double iron planes became what retailers had available. Double iron planes, though, were made in only one pitch. British makers settled on 47 1/2º and American makers offered only common pitch (45º). Even the revered infill planes were only commercially made at 47 1/2º, a lot of people claim they are York pitch but York pitch is 50º.

Double irons simply don't work as well as traditional cutting geometry. For a cap iron to even begin to be as effective as a steeper pitch on difficult grain it has to be set within .004" of the cutting edge. 18th and early 19th Century woodworkers knew this and, as traditional pitches became less available, they turned to the used tool market for their bench planes. Collectors and historians have puzzled over the lack of surviving 18th Century bench planes and I believe this is why those early bench planes are so scarce when molding planes from the same period are common. The old single iron planes in traditional pitches were simply better, were sought out and used up.

It seems ironic to me that people are discussing lowering the quality of cap irons to save money since that was their purpose in the first place.

[mrgrimsdale]

Aug 25, 2008 10:44:16 GMT lwilliams said:

snip
The old single iron planes in traditional pitches were simply better, were sought out and used up.

Interesting piece but a dubious conclusion IMHO. There is a simpler and more obvious explanation - that old single iron planes were not sufficiently superior in performance to merit the extra cost, and so were eventually replaced, as they wore out, by double irons. Also double irons (thin blades) are easier to sharpen.
Whereas moulding planes stayed in use much longer, staying useful even well in to the machine age.

If the steeper pitch is an advantage, why not double iron planes at steeper pitch?

cheers
Jacob
PS and of course - planes get much more physical use by far, than any other tool, in a hand work shop. So will be worn out regularly and disappear for ever.

[mrgrimsdale]

Aug 25, 2008 10:01:56 GMT engineerone said:

snip

as for jacob's idea, in joinery i can see that, but surely if you have cut your piece to length, then having nails which bite into the sides and an end mean it is more difficult to make it look good on the visible portions.
snip

Not my idea it's common practice.
You plane the edges to size after thicknessing - which is also universal standard practice. You lose the tiny nail head marks in the process.

cheers
Jacob

[thebloke]

The reason that shavings get jammed is simply one of space, moving the breaker back a tad gives a bit more. However, on many planes the leading edge of the mouth is generally square. If you upend the plane in the vice and take a warding file to the casting and relieve it by about 15 deg or so, then polish with a bit of w/d paper wrapped round stick, it makes a considerable difference. There should still be a tiny bit of the mouth that's square (maybe a mm) but the rest should be sloping. The breaker can then be set as close to the edge (about 1mm for a smoother and 1.5 say for a jack) as you want without jamming...works for me
If Mr Grim wants to bang nails into his bench, remind me never to invite him to use mine ;D... - Rob

[lwilliams]

Aug 25, 2008 13:02:04 GMT mrgrimsdale said:

Interesting piece but a dubious conclusion IMHO. There is a simpler and more obvious explanation - that old single iron planes were not sufficiently superior in performance to merit the extra cost, and so were eventually replaced, as they wore out, by double irons. Also double irons (thin blades) are easier to sharpen.
Whereas moulding planes stayed in use much longer, staying useful even well in to the machine age.

If the steeper pitch is an advantage, why not double iron planes at steeper pitch?

cheers
Jacob
PS and of course - planes get much more physical use by far, than any other tool, in a hand work shop. So will be worn out regularly and disappear for ever.

It's not dubious at all, Jacob. One thing the current "bevel-up" fad has shown, beyond doubt, is that cap irons aren't necessary or even desirable. Why tinker with something that only slows you down and can cause some major problems.

Lie-Nielsen is now offering double iron planes at York and middle pitch. I haven't used them so I can only guess at their performance. I'll bet, though, they work just fine. I'll also bet one will have far less choking problems with them if they back the cap iron off to where it basically serves no function when it comes to tear out. I know this is the case for Norris planes and I'd expect the steeper pitches LN is offering to cause even more difficulty when the cap iron is set close to the edge.

At the time double irons were introduced, bench plane irons were quite thin, about 1/8" or less. We've made single iron bench planes with irons of the same thickness and they work just fine. The only difference we could find is that the cutting sound was at little higher pitch.

Unfortunately the current crop of 12º low angle, bevel-up bench planes aren't suited very well for what they're marketed to do. Just like the earlier Stanley versions, they're suited for use with a 25º cutting bevel and for very light cuts. These planes just lack the necessary clearance angles for use as they're marketed. Stanley understood clearance angles and that's why they offered block planes in both 12º and 20º bed angles. Early plane makers and woodworkers also understood clearance angles. The miter plane replaced the strike block plane because sharpening the strike block requires very close attention to the bevel angle and resulting clearance angle.

[mrgrimsdale]

It just seemed to me unlikely that the whole trade would have given up single irons in favour of double irons, if there is no advantage. Especially as it is such an important and heavily used tool.
Perhaps they don't cut any better but there are other advantages?
Sharpening obviously quicker (less metal).
Keeping an edge longer perhaps? That's a likely one - as you get nearer to scrape instead of slice the edge is going to get more stressed I imagine.

Or the double iron could have been the tool makers way of getting more sales with a dubious "new improved" design. Looks more technical so must be better. Just a rip-off - like 90% of most tool catalogues today? ;D

cheers
Jacob

[mrgrimsdale]

Except for the block plane where the low angle makes it more compact for one hand use, what is the point of bevel-up planes?
I've just read various notes all over the pace but there is no answer. Why tilt the blade back to 20 or less deg, but then turn the cutting angle up by turning the blade over?
I could see an argument for going the other way - turn a standard frog angle bevel-down blade over, to get a steeper cutting angle for difficult grains etc.

cheers
Jacob
PS just read this www.traditionaltools.us/cms/index.php?name=Forums&file=viewtopic&t=153
seems to be nonsense from beginning to end!
PPS if:
you have a normal 30deg edge angle on a 20deg low angle plane but bevel up,
then:
your cutting angle is 50 deg i.e. higher than a conventional plane.

[engineerone]

well, jacob, when i re started hand planing, i found sharpening difficult, as admitted elsewhere

but with a bevel up plane i found it easier, also the whole set up of the plane is easier, because you have only two things to worry about, the blade and no chipbreaker. also the blade is supported over more of its length, so chatter is reduced.

it is also easier to obtain a "york" or coarser pitch and get easy adjustment for the blade protrusion. i have found that it is easier to get a decent finish on a piece of cherry, with its odd grain pattern with my 164 than the number 6 so personally this seems a useful tool.

in engineering we have a number of files to finish off the metal depending on the condition it is delivered in. from b*st*rd to fine
rasp to normal, and we often use them one after the other, and see no difference.

i think your prejudice about modern tools and being sold too much is perhaps blinding you to the value of these tools.

paul