Question About Bevel Up Planes and Chipbreakers

[Mark R Webster]

I have always used bevel down planes with the associated chipbreaker and with very difficult woods adjusted the chipbreaker down to minimize tearout. Can anyone explain to me why a bevel up works without a chipbreaker. I realize you couldn't really add one with the bevel up, but if the bevel up works without a chipbreaker why do you need one for a bevel down plane? Thanks

[Derek Cohen]

Mark

To control tearout on a BD plane, the chipbreaker is moved to a closed up position. The chipbreaker bends the shaving, pushing it back into the wood, and this reduces the distance the cut is made ahead of the blade edge.

To control tearout on a BU plane, the cutting angle is increased. When the angle is high enough (around 55 degrees), the cut moves from a shear to a scraping mode. Again, the cut is made at the edge of the blade rather than allowing it to form ahead of the blade, when it will tear (= tearout).

Regards from Perth

Derek

[Kees Heiden]

Like Derek explained , a BU plane controls tearout via the cutting angle (bedding angle + sharpening angle).

Both approaches work, high cutting angle or close set chipbreaker to combat tearout. According to my not so humble opinion, the chipbreaker approach is better. A high cutting angle asks for more pushing power, and the edge will wear out sooner. When you do most of your dimensiong with machines and you are only removing planner riples, then the point is probably pretty mood. But when you are dimensioning by hand, then a couple of nice wooden planes, bedded at 45 degrees with chipbreakers are optimal. Antique Stanleys with their lighter weight castings are a good second when you wax the soles of your planes regularly.

[Mark R Webster]

Thanks guys, your explanation, of the higher angle replacing the need for a chip breaker is helpful. I am still a little confused though. The Stanley bench plane is cutting at a 45° angle… the bevel up at 12° + 25°… so 37°. So the bevel up plane without changing the iron (bevel) is cutting at a lower angle right? In general wouldn’t the Stanley perform better with potentially less tear out? (not talking about end grain here) I understand the ease in changing the cutting angle with the bevel up versus the fixed frog angle of a Stanley for difficult grain. But, wouldn’t one expect that in the “stock” formats (without altering the iron), the Stanley would perform a bit better in more difficult woods?

[Derek Cohen]

You have to compare apples with apples. The stock Stanley, with a cutting angle of 45 degrees, and used without the chipbreaker, will have a higher cutting angle than a BU plane with a 25 degree bevel (12+25=37 degrees). No one should use a BU plane this way, and so this comparison is meaningless.

Set up the BU for interlocked timber, and you are likely to add a 50 degree secondary bevel for a cutting angle of 62 degrees. That will blow away a Stanley without a closed up chipbreaker. The Stanley only comes alive, in this situation, when the chipbreaker is closed up. The use of chipbreakers was largely forgotten up until 2012, when the forums began exploring it again. BU planes were very dominant around that time because they work well on interlocked grain (as long as the cutting angle is high). For some they are still preferred as the bevel is easier to hone high than setting a closed up chipbreaker.

Regards from Perth

Derek

[Mark R Webster]

"No one should use a BU plane this way, and so this comparison is meaningless"
Hi Derek, please don't take this as a challenge to what you are saying that is not my intention (I am just trying to understand). If the bevel up is not intended to be used with a 25° bevel, why is it sold with one. Is it because it is primarily intended to be used on end grain and secondarily side grain with a higher angled bevel. Do you personally use a bevel down plane for your side grain work and reserve the BU for end grain or with a modified bevel for difficult side grain?

[Derek Cohen]

Hi Mark

I hope my post did not come across as aggresive. That was not my intension.

Up until about 4 years ago, my go to type plane was a BU, as I needed high cutting angles for the wood I work with. Today I prefer BD planes with chipbreakers. The BU planes are still used, but mainly with lower cutting angles on end grain and cross grain.

The reason BU plane comes with a 25 degree bevel is for end grain. This is how they were originally offered, such as with the original Stanley #62. Add your own higher secondary for face grain.

Even BD planes often come with 25 degree primary bevels. They should not be used at this angle, but with a minimum of 30 degrees for longevity.

Regards from Perth

Derek

[Mark R Webster]

Thanks for your clarification it make perfect sense to me now. I appreciate expertise!
Mark

[Prashun Patel]

I will also add that if you do not work in difficult woods then the original bevel in a bu plane may work just fine when sharp.

[Mark R Webster]

Yes I have experienced that as well Prashun thanks. This thread has be enlightening for me.

[Bill Houghton]

Mark,

You might find it helpful to see what books your local library has on the subject of hand tool woodworking. Most of the classic books, and many of the new ones, cover the question of why there are low-angle bevel-up planes, among many other topics. Although it's unlikely your library will have it in stock, there's a British book, "Planecraft," now out of print (the original, anyway; there's a remake) as far as I know but still available (about $6 on the online site where I just looked), that addresses a lot of these questions. The original, by Hampton and Clifford, is better, mostly, than the remake by John Sainsbury; but they're both pretty good. With the original, you do have to be comfortable with between-the-wars British phrasing and word choices; if you find that challenging, go for the Sainsbury remake.

I feel like a broken record sometimes; and I know not everyone learns by reading. But books by knowledgeable authors offer you a more comprehensive look at any given subject than about any other source besides a long apprenticeship in the trade (and even formal apprenticeships involve a lot of reading, or traditionally did, anyhow).

Once you're grounded in the theory, of course, nothing beats putting the tools to work, where you'll find out why the "rules" exist, and when you can violate them.

Bill

[Mark R Webster]

Thanks Bill... sound advice!!

[Todd Stock]

The Stanley only comes alive, in this situation, when the chipbreaker is closed up. The use of chipbreakers was largely forgotten up until 2012, when the forums began exploring it again.

If I could offer an edit, insert 'by some' between 'forgotten' and 'up until...'

[Stewie Simpson]

A bevel down high angle approach also works well at controlling tear-out on interlocking grain. But not all types of wood will behave the same. What may work at 50 degrees may not be enough to control tear-out on wood with a higher density and Janka. By adding a 10 degree back bevel on the following 50 degree York Pitch single iron wooden smoothing plane, the effective approach angle was increased to 60 degree Cabinet Pitch. It worked a treat.

[Mark R Webster]

Very nice!!