Unicorn and Bevel Up

Re: Unicorn and Bevel Up

Wiley Horne

“.. what I've found out so far is that a 45 degree total bed (25 degree blade, 20 bed on the 18) seems to match tearout performance of a 55 degree blade, but feels closer in push resistance to 45 degrees ”

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This is a very big deal if it can be replicated in repeat tests, and by others. Good news for those owning BU bench planes, and shooting planes too.

Wiley

Re: Unicorn and Bevel Up

David Weaver

For the 18 and it's kraft singles hardness blade, the extra strength to the edge is good (45 effective honed is just 25 degrees at the edge), so buffing that to try to match the 55 degree tearout performance just greatly improves the feel of that plane in general.

For the low bed angle, it'll be interesting to see what the feel is (I'm going to need to make a couple of extra blades, but I'd rather make them than buy them - I can sell the extra blades on ebay as people are probably dying for O1 versions).

Extras needed so that I can get a quick change feel from one to the next, of course.

At any rate, I'm slowly getting to the point - 34 is where I see chisels suddenly stop taking damage. the 18 doesn't allow me to have an angle like that without being at 55 degrees or close. The LN LA jack will allow a 46 degree total angle at that to compare to 25 and buffed, etc. It'll be interesting.

My rambling incoherence from yesterday other than the smoothness was sort of along the line that I realized that on baked and non-baked very figured maple, just about anything will plane the edge cleanly - so some care will be needed for testing (as in, I"ll have to use the plane some instead of just taking test passes) to make sure the three categories of relevance (in my mind) are covered:

* clear softwoods and medium hardwoods

* figured and curly medium hardwoods

* torture woods like the bubinga and quartered cocobolo that I tested the 18 on initially.

A test with bevel up planes, buffing, and tearout

Winston

I did some experimentation with tearout control with buffed blades. My experience seems to be very similar to David's.

Overall, I'd say that the pushing resistance isn't noticeably increased by the tiny bevel added by buffing the blade. But the tearout resistance is better. And of course sharpening a bevel-up plane this way is very quick and easy, and you don't have to be as careful about clearance angles as you do with bevel-down planes.

Regarding pushing resistance, it wasn't noticeably increased for me, though I supposeiIt's possible that someone with a better-calibrated arm might notice something.

I don't have any exotic woods laying around and I don't really use them. I did find some black walnut that had a section of reversing grain. This is what it looks like from the side.

For testing, I used my Veritas low-angle jack (bevel-up) with a 12-degree bed, and a #5 (bevel down) with the standard 45-degree bed. In the Veritas, I used some blades buffed, and some not. For the buffed blades, they sharpened on a Shapton 1000, then Sigma Power 6000 (working the bevel and the back), then buffed with 1 micron green compound. For the non-buffed (flat-honed) blades, I used the 1000 and 6000 stones, then a Shapton Pro 12000.

I tried to take a reasonably fine shaving, like .0015"-.002". With the bevel-up plane, I closed the mouth so it was pretty tight.

Below are pictures of the piece of wood after planing with various setups.

*****

Bevel-up 25 degree (on 12 degree bed), buffed. There was a bit of tearout.

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Bevel-up 32 degree (on 12 degree bed), not buffed. This had a 44 degree cutting angle, very close to that of a bevel-down bench plane.

There was tearout with the cut I was taking (around .0015"-.002")

After that, I tried taking a very light cut. There was no tearout in this case:

*****

Bevel-up 32 degree (on 12 degree bed), buffed. The resistance to pushing didn't feel noticeably greater than the flat 32-degree blade.

There was no tearout.

I also tried taking a very heavy cut and got tearout. This was a much deeper cut than I would use in the smooth-planing, and it was deeper than what I tried with any other plane/blade combination in this series of tests, but I wanted to if I could get tearout with this setup, and the answer is yes. I think the depth of the tearout was limited by the tight mouth, though.

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Bevel-up 45 degree (on 12 degree bed), flat. This had a 57 degree cutting angle. Noticably more resistance to pushing than the previous ones.

There was no tearout. However, the surface quality wasn't quite as good as with the lower angles. It's pretty subtle, but in the pictures, you may be able to see that the surface is slightly more matte -- there's less contrast between the dark and light areas. I think this is because the blade had more of a scraping action here. Again, the difference in surface quality is subtle.

*****

For comparison, I also used the #5 (bevel-down) plane. For these tests, the blade was buffed on the bevel side.

Bevel-down (45 degrees) with the chipbreaker set far back (around 1.5mm).

As expected, this setting had tearout. The cutting angle is 45 degrees, which is close to the bevel-up plane with a flat-honed 32-degree blade -- that one had a 44 degree cutting angle, and of course, no chipbreaker. In terms of tearout resistance, this plane's chipbreaker was too far back to help at all.

The tearout in this case was slightly worse compared to the flat-honed 32-degree bevel-up condition, and I think it's probably because this plane has a wider-open mouth. (I closed up the mouth in the bevel-up plane, but didn't bother to for this bevel-down plane, because it's a bit of a pain to do so.)

I tried taking a much lighter cut, and managed to avoid tearout:

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Bevel-down (45 degrees) with the chipbreaker set very close. This had the most resistance to pushing. No tearout.

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For bevel-up planes, buffing the blade seems like a clear winner: It makes it easier to get a perfectly uniformly sharpened blade, reduces tearout at any given bevel angle, but doesn't significantly increase pushing resistance. It also increases edge durability, as I found when I tested buffed blades in a plane used for shooting.

I don't think this will make bevel-up planes able to completely replace bevel-down planes with respect to tearout control, but I think it can make them more versatile.

*****

I should also mention that although unicorned edges are more durable, they are not indestructible. I was using the 25 degree buffed blade for some actual work, and planed through a very tight knot in cedar. It caused visible damage to the edge (which in turn left visible tracks). You can seee that the center of the blade doesn't reflect the same way as the rest of the blade.

Here's the damage viewed through the microscope:

Re: A test with bevel up planes, buffing, and tear

David Weaver

What you're showing is why it's difficult to make a magazine type article or tutoring for a bevel up plane.

If you discuss taking a thick shaving, most readers will just see that nothing seems to cause tearout and they'd never use the thick shaving, anyway.

I subjected my blades to yellowcake, so they may have more wear on them. Going above about 3-4 thousandths in hardwood in the block plane is prohibitive so I didn't see much tearout in anything other than ribboned khaya - and that was just a little.

I'm assuming my BU jack will arrive this week. I've been down this road in the past and had a BU jack and BUS. There's no chance that I'll replace my stanley with anything with a bevel up blade, but I figure that covering using the buffer may tie up some remaining loose ends (it makes an almost intolerable soft iron in a guide - something I already hate to use) a lot more tolerable because there's no trap of using the guide without the easy nuance of working back and forth to tease off the wire edge.

With the buffer, the fast cut of the sharpening stone in the soft iron and the chewy wire edge are both just blasted off.

Re: Unicorn and Bevel Up

Kent B

Gentlemen:

You are at a different spot than I on the space-time continuum. But I do try to keep up, and this specific conversation answered many of my questions.

I'm not 100% clear on the details of the Uni-verse, but got enough to know that if I do my normal routine through Shap 12k then buff with green stuff, I should see an improvement, as my skills get dialed in. Thus, I have a Winston-version cordless drill wheel inbound.

And so - thanks.

Re: A test with bevel up planes, buffing, and tear

Winston

> What you're showing is why it's difficult to make a magazine type article or tutoring for a bevel up plane.

>

> If you discuss taking a thick shaving, most readers will just see that nothing seems to cause tearout and they'd never use the thick shaving, anyway.

There's definitely more complexity and nuance in assessing the performance of planes, compared to chisels.

My Veritas low-angle jack has been mostly sitting on a shelf. I've preferred bevel-down planes due to better tearout control and easier cambering. Now I may start using it more, using a 32 or 35-degree bevel and buffing.