hand plane chip breakers

[paulchapman]

Aug 26, 2008 7:49:07 GMT mrgrimsdale said:

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.

With the development of the Bailey-style metal plane and its adjustment mechanism, you need a cap iron in order to engage the 'Y' lever to adjust the depth of cut - so that's probably why double irons have predominated. Of course, the advent of the double iron gave those cheapskates at Stanley the opportunity to reduce the thickness of their blades. Thank goodness newer manufacturers like Clifton, LV and LN have gone back to thicker blades.........

Cheers

Paul

[mrgrimsdale]

Aug 27, 2008 10:40:51 GMT paulchapman said:

snip
With the development of the Bailey-style metal plane and its adjustment mechanism, you need a cap iron in order to engage the 'Y' lever to adjust the depth of cut
snip

Paul

Why? Plenty of other ways to design for adjusting a blade, and simpler.
I'm inclined to the view that the conventional arrangement we now have is simply the best compromise, which is why it was taken up so enthusiastically by the trade.
Keeps edge longest, quicker sharpening, cheaper.
Sharpening time praps the most important - planing oak means 25% of time spent sharpening, if done by hand. Big saving possible here.

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

Not a prejudice, I'm just asking! Yes I do have a prejudice abt spending more than I need to.

[paulchapman]

Aug 27, 2008 10:58:27 GMT mrgrimsdale said:

Why?

Because that's how he designed it........

[mrgrimsdale]

Aug 27, 2008 11:03:26 GMT paulchapman said:

Aug 27, 2008 10:58:27 GMT mrgrimsdale said:

Why?

Because that's how he designed it........

Hmm. Circular argument? Need a cap iron cos that's how it's designed?
Why design it that way? Answer IMHO is to spring down the blade-back, on to the frog.

cheers
Jacob

[engineerone]

prior to the bailey and the bedrock patterns, almost no plane actually included a mechanical system to adjust the blade at an angle to the mouth.

in addition, the introduction of accurate, mass produced screw threads allowed for simpler incremental movement of the blade forward and backward within the mouth. prior to metal planes, as most of us know the adjustment by tapping with a hammer was much more "hit and miss" ;D

the "y lever" operates in an arc so it both stops the blade moving too far, back or forward, and allows small incremental movements.

with both those designs, the "y" lever operates on the cap iron/chip breaker, rather than the lever cap to give it one name.
this is because the blade and chip breaker are co joined, whilst the cap breaker is separated.

since the lever cap was acting as a compressor, it would not be able to act on the movement of the blade. in the same way that a wedge on the wooden plane only holds the blade once the blade has been set. the only way to incrementally move the blade is to place a spacer/shim between the sole of the plane and some flat surface. whereas with a metal plane, the screw thread is more accurate, and the cap iron stops it moving around.

one interesting thing which has been discussed elsewhere is that to add thicker blades and chip breakers, it is often necessary to extend the length of the "y" piece. paul chapman has shown this before. by definition therefor one would think that the investigation into production costs and incremental cost reductions have basically made most mass produced planes along the lines of a lotus racing car, ie only marginally strong enough to carry out the job.

paul

[mrgrimsdale]

mass produced planes .... only marginally strong enough to carry out the job

Strong enough - they last for generations if they aren't dropped too often.
My Record 5 1/2 (best plane in the universe ;D ;D) and my Stanley 220 have been going strong for 36 years from new.

cheers
Jacob

[thebloke]

Aug 27, 2008 11:45:20 GMT engineerone said:

it is often necessary to extend the length of the "y" piece. paul chapman has shown this before.
paul

It's me what did for him ;D. I modified a couple of 'Y' levers on my planes (as I was fitting thicker blades) and then I did a few for Paul... btw Clifton 'Y' levers are made from some sort of alloy only slightly harder than cheese - Rob

[mrgrimsdale]

Nobody has come up with an answer to what is the point of a low angle BU plane except that you can do without a cap iron and it makes a one-hand block-plane more compact.
Is that it then?
You can only do fine shavings with a LA BU. They dig in and tear out if too deep. You can also do fine shavings with a double iron bevel down plane, and coarse ones too.
Is it that amateur woodworkers are seduced by the hint of fine shavings only failing to see it as a limitation rather than an advantage?

cheers
Jacob

[Alf]

Sorry, Jacob, saving up all my ire and irritation for the UPS man. Also find banging my head against a brick wall slightly futile after a bit.

[jay]

I take quite thick shavings on occaision with my LABP - a block plane's job is stock removal in small areas.

I'd have thought that the advantage of the bevel up bench planes was that it can be quickly adjusted (including the mouth) for shavings of various thicknesses. Not sure why you couldn't have an adjustable mouth on a bevel down plane mind - only they seem to have complicated frog assemblies to do the job.

[mrgrimsdale]

More stuff here from C Schwarz: popwood.com/articledisplay?id=17768
Bevel up + no cap iron: steeper angle of attack, better on difficult grain, no cap iron blocking mouth, but harder work. Also IMHO will need sharpening more often (as the angle approaches a scrape) and will need a heavier blade to resist chatter (cap iron helps chatter by holding the blade down). Heavier blade means longer sharpening (more metal).
So all in all its a tangled web of trade-offs and compromises.
With IMHO the conventional cap-ironed 5 1/2 jack occupying middle ground as best all-rounder ;D
But I knew that before I started

cheers
Jacob

[engineerone]

as usual jacob you have chosen to re-arrange the argument for your own benefit ;D

plainly if people like stanley, record etc made diverse planes, there has to have been a reason that they thought they were of some extra benefit.

as for your argument about bu's that is truly spurious.

bu's can take pretty thick shavings, but why should they??
the whole thing about planing in the modern age is that
most people who turn to woodworking have no training,
and so taking larger shavings is hard work, and gives you
the impression that your planing skills and the plane are no
good.

thinner shavings may take longer to allow you to achieve the
end that a trained pro might take, (if he actually uses a hand plane : but in a longer time, and maybe as an amateur, giving you more satisfaction.

if we are being practical, and were to carry out a survey, i would guess the most bu planes are bought by those who do not work wood for a living, but who see it as a useful skill, and valuable relaxation. however they also want to get results in this lifetime.

bu's have the bonus of not requiring a degree in brain surgery to present the blade to the surface quickly and accurately, where as bd planes setting is a complex operation, even when practiced at it.

anyway my head hurts from trying to convince you to be open minded ;D

paul

[mrgrimsdale]

I was just paraphrasing Mr Schwarz - he said it! Plus some IMHOs of my own.

cheers
Jacob

[ivan]

May I suggest a browse here?
planetuning.infillplane.com/html/chipbreaking.html
Thin blades and thin chipbreakers vibrate and bend (shown with my dial gauge) this may not be a problem, but for finest cut a thick blade is better than a chatter tool, no? On mass produced planes the bend probably made sure something near the sharp end was actually touching the frog (on my circle plane, it didn't even there).
You don't actually need a bent chipbreaker, rolling a burr on a flat one, scraper plane style is quite enough. Ellis suggests using a piece of broken saw file (those were the days) scraped over the join of blade/breaker if shavings still get caught. It works too.
You can see from the link that a close set chipbreaker/blade mimics the cutting geometry of a scraper plane with the extra advantage of a narrow mouth. Note the bevel on the edge of the mouth to prevent the clogging other have posted about. Close means really close - even the oft quoted 1/64 is too much. But only of importance for quality cut. For what it's worth I've made some chipbreakers similar to LN with a 70 deg burr as mentioned above, as blade and breaker can be both crowned and very close set. If you try to crown a Clifton breaker, say, the edges of the chipbreaker won't touch the blade (bit of geometry) and you have a shavings trap at each side.

BU planes with no chipbreaker appear to produce a sort of wooden chipbraker effect when sharpened at very high angles as the steep angle begins to add a bit of scraping action. (See pix in Lee on sharpening) BD+ cap iron may give beter surface? If you haven't got a BU plane sorting a really close chipbreaker may save youmore than a few quid!