confusion on the use of the chipbreaker

[Prashun Patel]

I've been using a close-set chip breaker for a couple years. It does indeed mitigate tear out, regardless of the bevel angle, and I have not found that it affects the finish quality of the surface at all.

I've never been one to mess around with the frog.

I will say that the most dramatic improvements in my planing quality have come from 1) improving my sharpening, and 2) learning how to read grain direction. If I were to start again, I would focus on these two things for years before looking to altered angles.

All this assumes of course that you have a properly set up plane; namely that your sole, breaker, and blade are all flat and true at the business ends.

[Kevin Jenness]

I did experiments on the clearance angle about 45 years ago. The clearance angle is the angle between the sole of the plane and the lower part of the edge. For a bevel down plane, the clearance angle would be the difference between bedding angle ( usually 45 degrees) and the honing angle (I use 30).

I have used a wooden trying plane and a wooden jack plane at 33 degrees for about 43 years. I have used a Bailey type plane altered to have a bed at 32 degrees. These are very marginal improvements over 45 degree beds, but they require more discipline in sharpening. I sharpen at 30 degrees with no microbevel, secondary bevel, just flat honing.

Warren, are the blades in your trying and jack planes set bevel up? Is the 32* bed on your Bailey plane a typo? I don't understand how such a low bedding angle on a bevel down plane can provide a sufficient clearance angle if the edges are at 30*.

[Warren Mickley]

Yes, thanks Kevin. I should read 43 degrees and 42 degrees for the beds. 40 degrees is near the lower limit for a bevel down plane. I will change the original posting.

[Kevin Jenness]

Yes, thanks Kevin. I should read 43 degrees and 42 degrees for the beds. 40 degrees is near the lower limit for a bevel down plane. I will change the original posting.

Oh, that makes more sense. Your answer to my question about planing difficult woods on a previous thread led me to tune up my smoothing plane and set the chipbreaker quite close to the edge. What a difference that made!

The Japanese video on chipbreaker setting cited earlier https://vimeo.com/158558759 is an eye-opener. I assume the performance of super surfacer machines depends in large part on this adjustment.

[Rafael Herrera]

The chipbreaker debate was about 10 years ago by now. It's an interesting read. There were very vehement advocates of higher angle beds, closed mouth setups that were sure that the chipbreaker (or cap iron as some insist on calling it) were useless. The chipbreakers were introduced in the mid 18th century and dominated the hand plane design up until they were replaced by machinery in the professional workshop.

Some argue(d) that their function was to stiffen the iron, there were no thin irons when the chip breaker were invented. In this picture a typical wooden plane tapered iron (right, approx 3/16" / 5mm) next to a metal bench plane iron. The chip breaker was not used to stiffen it.
USER_SCOPED_TEMP_DATA_MSGR_PHOTO_FOR_UPLOAD_1584322558355.jpg

During the hobbyist woodworker revival the new planes brought into the market came fitted with chip breakers that would not function as they were supposed to, later to be corrected. I gleaned all this from the forum discussions of that time.

Higher angles and narrow mouths work, but a $30 Bailey pattern smoother can be tuned to perform similarly or better and also be used for coarser work.

This video shows one of those super surfacer machines in action. Note how the shavings come out as straight sheets? That's due to the chipbreaker in action. Similar shavings can be produced with a hand plane. When the chip breaker is not engaged, the shavings will curl.

https://youtu.be/eaClhzlpc_0

[Kevin Jenness]

This video shows one of those super surfacer machines in action. Note how the shavings come out as straight sheets? That's due to the chipbreaker in action. Similar shavings can be produced with a hand plane. When the chip breaker is not engaged, the shavings will curl.

https://youtu.be/eaClhzlpc_0

Excelsior!

[Warren Mickley]

I started using the double iron for tear out in 1973, as a result of reading historical references from the 18th and early 19th centuries. I started advocating for double iron use at the time I started participating in online forums around 2006. My posts were continually discredited by those with much less planing experience and little knowledge of historical practice.

My first convert to using the double iron was Bob Strawn, who learned in 2009-2010. David Weaver reported success on 3/26/2012. Here is a post Bob Strawn wrote on this forum:

https://sawmillcreek.org/showthread....de-chipbreaker

Plane irons were thin in the 18th century when double irons were first recorded., roughly 1/8, or sometimes a little less. The Seaton Chest book has some late 18th century measurements. I don't know why plane irons became thicker in the 19th century.

A cap iron set too close results in a cloudy appearance on the wood. This is more noticeable on the more tender woods.

[Assaf Oppenheimer]

Prashun, if you are asking if my planes are set up the answer is... I hope so.

I am self taught, and my planes are Lie Nielsen's for the simple reason that I would rather assume that the problem is with me, rather then figure out of it is an issue of skill vs tool quality. I began to believe I am adequate after I successfully laminated a 4 inch benchtop of 8/4 material gap free. it might have been faster to try and grow the tree to the dimensions I wanted but I got there....

[Rafael Herrera]

Plane irons were thin in the 18th century when double irons were first recorded., roughly 1/8, or sometimes a little less. The Seaton Chest book has some late 18th century measurements. I don't know why plane irons became thicker in the 19th century.

I've only had access to 19th century irons so far, although I think I may have a 17th sample that is tapered, I need to look more deeply into it. I didn't know they were manufactured thinner earlier, perhaps a manufacturing requirement? cast steel replaced blister steel in the late 18th century, could that have affected the methods of production?

[Assaf Oppenheimer]

For BD planes, a 32-35 degree bevel is going to produce the strongest edge. The bevel angle is not going to affect the cutting angle for a BD plane.

interesting, Ill begin changing the angle as I progress in my sharpening.

[Assaf Oppenheimer]

That. is. ridiculous.

[steven c newman]

Currently, there is an Ohio 035 in the shop...and it does have a thick, tapered iron....and a wooden Razee body like a Stanley No. 35.

[Jim Koepke]

Some argue(d) that their function was to stiffen the iron, there were no thin irons when the chip breaker were invented. In this picture a typical wooden plane tapered iron (right, approx 3/16" / 5mm) next to a metal bench plane iron. The chip breaker was not used to stiffen it.

Here are a couple of paragraphs from Leonard Bailey's patent for his design of the cap iron:

Bailey's Patent Cap Iron.png

The full copy can be found at > https://pdfpiw.uspto.gov/.piw?PageNu...&docid=0072443

Some of the early cap irons sat flat on the blade iron and did not have the tensioning effect of the Bailey cap iron.

If earlier cap irons were used to control tear out, then Bailey needed a different reason to patent the set up of his thinner blade and cap iron.

jtk

[Rafael Herrera]

Here are a couple of paragraphs from Leonard Bailey's patent for his design of the cap iron:

Bailey's Patent Cap Iron.png

The full copy can be found at > https://pdfpiw.uspto.gov/.piw?PageNu...&docid=0072443

Some of the early cap irons sat flat on the blade iron and did not have the tensioning effect of the Bailey cap iron.

If earlier cap irons were used to control tear out, then Bailey needed a different reason to patent the set up of his thinner blade and cap iron.

jtk

Jim,

His 1858 patents use double irons, https://pdfpiw.uspto.gov/.piw?PageNu...&docid=0020615, albeit they seem to be of the tapered type.

I would venture say that Bailey was still improving on his design by thinning the cutting iron of the double iron assembly, not introducing the cap iron in the design, it was already part of it. He came up with a modification of the cap iron to make the thinner iron work. The cap iron function, as a means of deflecting the shavings, was not hindered.

There's an interesting article in the TATHS site of an early double iron smoother, estimated to have been used in the 1750s. Of note is that the screw to hold the two pieces together had not been invented yet.

https://taths.org.uk/tools-trades/ar...city-of-london

Conserved double iron from the TATHS article
SmootherFig03.png

Warren gave an interesting piece of information about thin cutter irons in the 18th century. The thinness of irons is mentioned in the article above, I missed that when I first read the article a while back. I don't have the Seaton chest book, perhaps someone could chime in.

[Keegan Shields]

Assaf,

I am also self taught and struggled until recently to get my LN 4 1/2 to perform the way it was supposed to. I tried some pointers from the members here about prepping the chip breaker and setting it close. It’s magical to use now. No tear out regardless of grain direction. Keep at it and things will click.

HNT Gordon has an excellent YouTube video on what happens to the blade edge as it wears. Really helped me visualize what is happening.