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Cambered another iron, HSS for comparison

Posted by is9582 on February 22, 2013 with No Commentsas , , , , , , , , , ,

This is somewhat of a continuation on my previous article, talking about the cambered iron in my old Bailey No.3.

Well, I got back to work on the 8/4 Pecan, and I’m still resolving some slight twists in the board. I’d resharpened my No.3’s iron last night, just before calling it quits, so I was able to just get right to it. After planing for a couple of minutes, I could tell the iron was again ready for the water stones. Before taking the iron out of the No.3, I got side-tracked by something shiny! No, really, it was something very shiny. I keep a couple of backup iron close to my workbench, and I noticed one I’d bought within the last 5 – 6 years. It is one of the High Speed Steel (HSS) versions made by Paul Williams in Australia. I’d originally purchased it as a replacement for an old Stanley No.6, but it was really just a wee bit thicker than that plane could handle. Actually, it probably would be fine in 99% of those old planes, but mine seems to be a mish-mash of different time-frames. That iron has just sat around the shop for the duration, and I figured I’d finally get another No.6 sometime in the near future. What I’d completely overlooked is that it would also fit neatly into a No. 4 1/2, and I have a nice Lie-Nielsen version of that plane. The original iron in my No.4 1/2 is cambered ever so slightly, just the amount that I handle at the water stones; no grinder work necessary.

So, the Williams iron just went to the head of the class, ready to change into a nicely cambered iron. Here is a photo of the iron, before I took it to my grinder. The photo isn’t the best quality (sorry), but you still may be able to see the similar markings as I described in my last article, when I planned to modify an iron from a straight edge to cambered.

Arrow is pointing to gentle curve I drew with a Sharpie.

Same iron as above, with the bevel up, as it’s a bit easier to see.

I have a pink friable 80-grit wheel on my grinder, that does a pretty good job removing metal, without imparting too much heat. Even though this iron is HSS, and should be able to handle a bit rougher treatment at the grinder, I still prefer to use a light touch. When going for a camber, I base my grinding on how much material I need to remove. With this iron, even though it’s a light camber (at least in my eyes), there is still a fair amount of metal that must go. I start at the two corners and start blending towards the center, until I’m getting close to my target shape. At that point, I begin to use one hand almost like a clamp, holding the iron on the rest and pivoting around a centralized position. This seems to blend the arc better than I can do, if I try to work each side on its own, all the way to the finish. 
I snapped another couple of photos, after I’d finished at the grinder, but before moving to my sharpening/honing water stones.
Back of cambered iron straight from the grinder. Arrow pointing towards camber.
Bevel side of cambered iron, before honing.

I used my basic honing guide and set the iron so I’d hone at 35 degrees. Since the back of the iron had a substantial burr, from the grinding, I made some light side-to-side passes on my 1000-grit water stone. It took a minute or two to hone up through 8000-grit, and the iron was ready to work.

I installed this iron into my Lie-Nielsen No.4 1/2, and set it for a fairly light shaving. I easily planed for 15 – 20 minutes, with no obvious feedback telling me the iron was needing attention. Now this iron is HSS, and it is known for retaining an edge for a long time, but its also known it doesn’t get as razor sharp as high-carbon steel. From what I could tell, while working on the Pecan, this HSS iron felt like it could just as easily been a high-carbon steel iron. It was too similar to tell any difference.
The larger format No.4 1/2, along with its extra mass, sure helps when there is a lot of work to do. The extra mass keeps the plane moving through the cut, and the handles have enough room for the hands. The old Bailey No.3 was so small that I had multiple fingers hanging out, on my pushing hand, just so I could keep working. I still like it when I’m adjusting the edges on smaller projects, since that is usually fairly quick work.
I hope this might help answer any questions the last article generated. If not, please let me know and I’ll see if I can help.

Bailey No.3 with camber – assessment (updated)

Posted by is9582 on February 21, 2013 with No Commentsas , , , , , , , , ,

I have a number of Lie-Nielsen hand planes in my kit that work beautifully, but I also have an old Bailey I bought many years ago, that was set up differently than I’d ever seen, at the time of purchase.

What made the No.3 a bit unusual to me, at that time, was the somewhat shaped iron (cambered). I’d only ever seen/used planes with a completely straight cutting edge, especially in the small smoothing style of plane, like the No.3. At the time of purchase, I checked to make sure the plane operated correctly (as in holding and advancing/retracting the iron properly) and was sound, but didn’t pay much attention to the cutting edge, as I knew I’d need to sharpen it before use. It was only after I got home that I noticed the shallow camber on the iron. Since this was early in my quest to work wood, I was a bit sketchy in my ability to sharpen, and much less skilled still, at honing a shaped iron. The old plane (turn of the 20th century) still had a good deal of iron left, so I almost re-shaped the iron to a straight cutting edge. Luckily (as it would turn out), I’d bought a couple of planes at the same time, so I left this one alone and came back to it some years later. 
During the passing time, I became much more adept at sharpening/honing. So when I finally came back to the old No.3, I honed it up on both my 1000 & 8000 grit stones, and then tested it out. It was really an eye-opener, as the camber really provided a level of flexibility that I’d not experienced with my straight irons. I could much more readily focus on a specific area of a board, allowing quick (in many cases) controlled adjustment of both out-of-square edges and faces that were anything but flat.
The iron in my old No.3 is a Stanley laminated or “Composite” (cutting edge is a piece of steel with a higher percentage of carbon that is welded to a steel backer that contained less carbon) iron. The old iron sharpens/hones easily on water stones and takes a very keen edge. 
Until recently, I’d primarily use this plane when adjusting the edges on thin boards, which it did nicely and seemed to retain the edge for a long time. Yesterday I was working on some 8/4 pecan (a little over 4″ wide and about 35″ long) that had a twist on the face as well as the original bandsaw lines. I was about to grab a larger plane, but thought I’d see how this old baby responded. Just as the No.3 had behaved so many times, it started out teaching the wood who was boss. But, that didn’t last very long, as I started noticing how the depth acted as if it was winding back into the plane. I checked the lever cap and it was adequately snug, so I knew that wasn’t happening. When I pulled the iron, it was dull, so I quickly brought it back to life on my water stones. I went back to work and in a fairly short period of time (a couple of minutes), it was again showing the same signs. I pulled the iron again, and I was somewhat surprised to see just how much change had occurred, to the portion of the iron that was touching the wood. (See photo below)
The very shiny area at the tip of the cutting edge is actually where the wood removed steel.
After seeing the quick change in the cutting edge, I took the chip breaker off, and examined the iron a little bit closer. The area of the iron that shows as very shiny (in the photo above), also generated a small but very tangible burr on the backside of the iron, very similar to what occurs on a sharpening stone. I guess what surprised me most was the magnitude of change occurring in such a small period of time, but have some thoughts that might offset the concern a bit. 
When using a cambered iron, the impact on the iron is quite a bit different, compared to a straight cutting edge. With a camber, a very small portion of the iron is actually contacting the wood, which on the surface seems like a big, DUH! Ok, bear with me here. So, when you have a smaller area of the iron contacting the wood, it’s much easier to push through the wood, right? With that being the case, I’m certain I advance the cambered iron much more than I ever could with a straight iron, especially when working to remove a fair amount of material, as I was on this pecan. If I had a straight iron exposed as far as I did the cambered iron, I likely couldn’t even advance the plane. It would just “dive” into the wood, and there it would stop. I would think the straight iron (of the same material) set for an equal depth of cut (if you could actually handle moving it along in the same type wood) might show the same amount of rapid wear, over a similar time interval.

Basically, the added strain on the much more focused area of a cambered iron, relates to the depth of cut, and of course partially the medium. It seems this elevated stress is also somewhat amplified, when the depth of cut increases beyond a certain unknown point. When a plane iron is used to take a very thin shaving, say in the .001″- .003″ range (somewhat arbitrary), the fibers trying to hold the “shaving” to the board are fairly easy to overcome. Now, as the thickness of the shaving increases, here comes that “unknown point” again, there becomes a point where the wood says “I don’t think so”, and a less favorable result occurs. This might be somewhat analogous to paring down to a line, with a chisel. Many of us have experienced that dreaded thickness, when you try to remove it in a single pass, causes the chisel to dive down into the fibers and is forced back beyond the target line. If the same material is removed with a few passes at a less aggressive depth, you retain control of the chisel and finish at your target line. So, if the cambered iron reaches that depth where the wood fiber’s influence seems to increase, it would seem reasonable the iron is stressed further, not only trying to severe the fibers but also fighting against their attempt to make the iron dive down into the wood. If I can keep the depth of cut at a reasonable level, I may just find the sweet spot where I can still rapidly remove a fair amount of material, without spending as much time at the sharpening station. Time will tell!

I’ll definitely continue to use a camber on the majority of my planes, minus the few very specific tools that must have a straight iron, such as my Shoot Board Plane, rabbeting planes and shoulder planes. Even though my current project in Pecan initially bread some concern, it ultimately led me to analyze the complete situation and validate the process for the future.

Thanks for reading my article and let me know if you have any questions or thoughts on this topic.