Chip breaker experiment: session four

[Derek Cohen]

Rationale

The conclusion after Session Three was (1) I had either not found the sweet spot for the very hard Jarrah I was planing, or (2) the effect of a chip breaker deflecting shavings is wood dependent.

Session Four

The plane is an unmodified Stanley #604 with LN chipbreaker (given a 70 micro bevel and slightly cambered) and a custom M4 blade.

This time around I chose a piece of Tasmanian Oak. For non-Aussies, this is (in my experience) similar in density to USA White Oak and also to European Oak. Tassie Oak is not an oak, however, it is a eucalypt. As such, it tends to be a little more interlocked. This piece was fairly typical.

How would I know if I was in the "sweet spot"? Well the video shows the shavings coming off the chip breaker vertically. This is why I have begun to think of the chip breaker (never again a "cap iron"!) as a "chip bender".

I set the chip breaker at a modest 0.3 (keep in mind that the chip breaker readings are slightly larger at the edge of the blade compared to the centre of the blade) ...

http://i13.photobucket.com/albums/a262/Derek50/Chip%20Breaker%20Experiment/Session%204/Session47.jpg

The mouth was "wide" at about 1mm. No effort was made to close it down as I normally would do for a smoother.

http://i13.photobucket.com/albums/a262/Derek50/Chip%20Breaker%20Experiment/Session%204/Session48.jpg

Here is the result ..

http://i13.photobucket.com/albums/a262/Derek50/Chip%20Breaker%20Experiment/Session%204/Session41.jpg

http://i13.photobucket.com/albums/a262/Derek50/Chip%20Breaker%20Experiment/Session%204/Session43.jpg

This was a good result. In the background you can see shavings from a chip breaker set back about 3mm. Those shavings are curled.

http://i13.photobucket.com/albums/a262/Derek50/Chip%20Breaker%20Experiment/Session%204/Session42.jpg

Of particular relevance here is that the planing took place into the grain.

http://i13.photobucket.com/albums/a262/Derek50/Chip%20Breaker%20Experiment/Session%204/Session44.jpg

The surface result was also superior - a shiny, clear and tear-out free finish ...

http://i13.photobucket.com/albums/a262/Derek50/Chip%20Breaker%20Experiment/Session%204/Session45.jpg

A close up around the knot reveals the absence of tear out ...

http://i13.photobucket.com/albums/a262/Derek50/Chip%20Breaker%20Experiment/Session%204/Session46.jpg

The second part of this session now moved to closing up the chip breaker to about 0.1 - 0.2mm ..

http://i13.photobucket.com/albums/a262/Derek50/Chip%20Breaker%20Experiment/Session%204/Session411.jpg

The result of this was very similar to Session 3, where the plane struggled to cut.

http://i13.photobucket.com/albums/a262/Derek50/Chip%20Breaker%20Experiment/Session%204/Session412.jpg

Clearly the chip breaker is now too close. However this is further evidence that it has a significant effect on the way the plane cuts.

For Part 3 the chip breaker was returned to the position of Part 1 ..

http://i13.photobucket.com/albums/a262/Derek50/Chip%20Breaker%20Experiment/Session%204/Session421.jpg

That particularly nasty piece of Jarrah (which is almost like end grain in the one section) was brought back. The #604 proceeded to plane this. The result was a little better than on the previous occasion, but not really that noticeably so. The board had some straight grained sections that were softer, and where the plane met this area, the shavings where long and straight. The surface quality was poor.

http://i13.photobucket.com/albums/a262/Derek50/Chip%20Breaker%20Experiment/Session%204/Session422.jpg

The LN #3 (with 55 degree frog, chip breaker set back 3mm) had its turn. The result was the same as before: decent surface to the touch, a noticeable improvement over the common angle #604 ...

http://i13.photobucket.com/albums/a262/Derek50/Chip%20Breaker%20Experiment/Session%204/Session423.jpg

The chip breaker in the LN was now adjusted to 0.3mm and the board planed again. The result was a significant improvement in the quality of the surface ..

http://i13.photobucket.com/albums/a262/Derek50/Chip%20Breaker%20Experiment/Session%204/Session424.jpg

This was repeated with the Veritas Small BU Smoother (with a 62 degree cutting angle). In the previous experiment the SBUS left a clearly better surface than the 55 degree LN #3. This time the SBUS was shaded ...

http://i13.photobucket.com/albums/a262/Derek50/Chip%20Breaker%20Experiment/Session%204/Session425.jpg

Neither LN nor SBUS produced shavings that were vertical. THis must be due to the high cutting angle.

Conclusions

There does appear to be a performance difference in the woods used thus far, indicating that the technique is likely to be wood dependent. The chipbreaker does, nevertheless, appear to be capable of improving the performance regardless of the wood type. However cutting angle does play a significant part as well, with a higher cutting angle still seen to be important for hard woods with interlocked grain.

Regards from Perth

Derek

[David Weaver]

If the jarrah does in fact have grain that turns entirely up into the face so that it's like end grain, that might be part of the problem. We generally don't use boards like that in medium hardwoods in the US because the way they take finishes isn't too flattering. But planing a board like that downhill would be preferable probably no matter the tool.

I'm not sure I have anything like that floating around in my shop but so far my experience with the stock stanley design is that it's been easier to get what I want out of it than has the japanese design or "improved" design. Strange for that to be the case, as conceptually easy as it is to understand the improved design since they're a bevel instead of a stamped curve, but that's the case so far (comparing both an infill panel with the old flat design, and a japanese plane - I can get a better surface out of the cheap plane so far when the wood is difficult).

Do you have any stock irons (that you otherwise have no qualms with) and stock chipbreakers around?

[Derek Cohen]

Hi David

I wouldn't use this section of Jarrah for furniture either! However it does have a grain - it just resembles end grain in looks (actually it was your comment on this that prompted me to write this as a description). It is just very interlocked. I will take close ups tomorrow if you wish. The point is that it tests the planes to the limit. Some dealt with it better than others. It is not about whether you or I would find or use such wood; it is about the way the different set ups manage the situation it creates. Could the chip breaker do it as well/better/worse than a high angle plane. Indeed, if this was end grain, then the lower, common angled #604 should have cleaned up (pun intended :) ).

For myself it was gratifying that I could find the sweet spot and plan into the grain on Tasmanian Oak. This does demonstrate support for the chip breaker. What I should add - took for granted (not good) - was that planing into the grain without the setting created a very rough surface, as typical of past experience.

Regards from Perth

Derek

[Randy Klein]

Where is sessions 1-3? I can't find them.

[Derek Cohen]

Hi Randy

I did not post Sessions 1 and 2, but mentioned in Session 3 that the pictures were available. I did post Session 3 here ... it is somewhere ... :)

Regards from Perth

Derek

[Philip Duffy]

Derek, Wonderfully informative posting! Thanks. Philip