Chip Breaker Question

[Tom Bender]

I will be starting into a few pieces in Mahogany. Just sharpened my planes and chisels. What setback should I use on my chip breakers?

[Kevin Smira]

I always use (and only use) about a 32nd of an inch. I only polish a very small strip on the back of my plane irons (Charlesworth ruler trick) and I make sure that strip is present when I set the chipbreaker. No more, no less.

[david charlesworth]

Kevin,

If your chip breaker has an appropriate relief angle, say about 1 1/2 degrees, you will be able to set it as close as you like. Ruler (0.5 mm) creates a back bevel of approximately 2/3 of one degree

If the mahogany has quartered faces which tear out, you will benefit from an ultra close setting, say between 4 and 8 thou of an inch.

Best wishes,
David Charlesworth

[Charles Guest]

I will be starting into a few pieces in Mahogany. Just sharpened my planes and chisels. What setback should I use on my chip breakers?

The setting would differ a bit between the different planes. Are you completely hand processing the lumber? If you're only using a smoother to clean up machine marks then plane an off cut to see what you're getting. If you don't need a super-close setting then don't use one. Start at about a fat 32nd with the smoother and then get closer from there if necessary. Alternatively, try a lighter shaving and don't move the cap. If machines have done all the heavy lifting, you won't need a thickish smoother shaving anyway and a very light shaving may be all that's necessary without adjusting the cap. Presumably there's a finished thickness you'd like to hit as well, so you can't just keep planing for the hell of it.

[Jim Koepke]

I will be starting into a few pieces in Mahogany. Just sharpened my planes and chisels. What setback should I use on my chip breakers?

This really depends on what you are attempting to accomplish.

For a #5 with a heavily cambered blade or a jointer #6, 7 or 8 it can be set back quite a bit.

It also depends on how thick of a shaving you want to produce.

For a smoother it can be set to be a little further from the edge than the thickness of shaving being cut. If the ejected shaving is crinkly, then you are either too close or the chip breaker is blocking the shaving's path.

In my experience an extremely light shaving never produces extremely deep tear out. Usually an extremely light shaving produces almost no tear out. When a rough spot does occur it can often be removed by selective planing in the opposite direction. Areas around knots may be impossible to fully control.

jtk

[Tom Bender]

As you say, machines will be doing the heavy lifting. The material I am using is good enough that there is no need to work with knots, at least on a finished surface. I genrally use planes for a few tasks;

* I have no jointer so I use a plane to get one edge or surface flat enough for the planer or table saw.

* Chamfering or rounding edges

* Correcting mismatches such as the top of a drawer if the dovetails are not perfect or cleaning up a glued joint

A block plane is good about half the time.

[Warren Mickley]

As suggested by others, we use different cap iron settings for various planes, for various shaving thicknesses and for different species and amount of figure. One of the advantages of doing stock preparation by hand is that by the time you are close to a finished dimension you have a great familiarity with the timber at hand. Otherwise it is as if you are walking into a darkened room where you have not been before.