I just got a LN #62 Low Angle Jack Plane and bought an extra blade. Both are ground to 25 degrees, but I’m curious what angles would be recommended.
I am not a pro, just build bookcases, cutting boards, etc. I use a jointer and planer to mill/dimension stock but want to use the 2 blades for final smoothing and general planing.
Thanks in advance!
Josh
Replies
If I'm doing the math right, the 12 degree bed plus 25 degree bevel (up) has you cutting at 37 degrees...a low angle compared to a standard bench plane's bevel down 45. If you want to regrind the second blade for "general smoothing" consider getting closer to 45.
You should look at the LN website. They have recommendations, like a 5 to 10 degree secondary bevel for smoothing, less for end grain, more for difficult grain. But really you should look at their recommendations.
I'd leave one as is, and grind the other at 45, as MJ said. Experiment. The 45 will give you a cutting angle of 57. Anything over 60 makes it really hard to cut.
The 25 on the other plane is about as low as I would go. Less than that, the edge can crumble very easily.
I have the tooting blade for my LN 62. It's really the only blade I ever have in mine now. It's great for rough work, or for flattening really wild grain without tearout. You still have to smooth afterward, but you don't have to worry about tearing out chunks. Great for flattening benchtops too.
To clarify, I was not suggesting grinding to 45. I was suggesting getting close to a finished angle of attack of 45...which would be a grind angle of 33 for the general planing option. In truth, used #4s are so inexpensive I think you'll be happier picking one up so you don't have to swap blades at all.
The second blade at 45 would be a good idea if you have a dedicated smoother all set and at the ready.
I think the preground blades for Lee Valley go up to 60 degree cutting angle. But I don't find it practical.
Swappable angles sounds like a good idea. But I never like it in practice. Too much futzing around. My Lee Vallet low angle smoother is a true low angle, and my Lie Nielsen has a toothing blade. It's been years since I swapped blades.
For hardwoods I hone a secondary bevel of 45 degrees, this will give an included angle of just under 60 degrees.
I work a lot in figured Cherry and have found it will cut without tear out. It typically will leave a smooth finish even when cutting without regard to grain direction. The high cutting angle results in more of a scraping cut.
It will be a little harder to push, and will dull quicker than a lower cutting angle, but the benefits make it a no brainer for me.
About the only time I use the standard angle37-40 is for end grain.
Do you use the 37/40 degree angle for shooting boards too or just specifically end grain?
The lower angles will work fine, and are actually better for edge jointing as long as you are able to plane with the grain. As that is not always possible the steeper cutting angle works best. Although I also keep 2 blades the steeper angle works so well it is usually my go to tool.
Hi Josh
If you are working with interlocked grain, which has a likelihood of tearing out, then a 50 degree secondary bevel is indicated. This creates a cutting angle of 62 degrees, and is pretty resilient to tearout.
The downside of high cutting angles is that they do not leave as clear a surface as a lower cutting angle, so you do not need to go this high with straight-grained and softer woods.
Keep the 25 degree for shooting end grain.
Regards from Perth
Derek
I imagine that a 25 degree blade would wear pretty quickly on the woods you folks have?
Hi John
The reason for a high cutting angle on a BU plane is not to safeguard wear, but to prevent tearout. And, yes, our West Australian woods, like Jarrah and She-oak, have much interlocked grain.
My go-to is not a high angle BU plane, but a BD double iron, where the chipbreaker can be closed down.
Incidentally, 25 degrees on a BU does not necessarily wear faster than a higher angle on a BD plane. Read this review I wrote of the Veritas shooting plane. It will amaze you (It did me).
http://www.inthewoodshop.com/ToolReviews/LVShootingPlane.html
Regards from Perth
Derek
Thanks.
I have three blades. One is ground at 35 degrees for an included cutting angle of 47 degrees. One is ground steeper (45 degrees) for difficult grain. The third is the toothed version and that’s ground at 30 degrees.
Not that this chat isn't always worth having, but the thread is just a month away from being locked at 2 years old.
Yes :) it popped up on my screen, and I replied.
Regards from Perth
Derek
I second Robes_pierre’s and Derek’s comments. I use two blades in my LN #62, one set up for shooting, end grain mostly, and one for smoothing challenging figured grain. I DON’T REGRIND the 25 degree bevel angle as it’s unnecessary; I just hone for the desired cutting angle.
My shooting blade is honed with a secondary bevel at 27 degrees, straight across, for an effective cutting angle of 39 degrees. The other one is honed with a cambered secondary bevel of 40 to 45 degrees (cutting angle 52 to 57 degrees) for challenging grain when my #4 smoothers aren’t quite up to it.
FWIW, I find LN’s hotdog very useful when shooting and just leave it on for other uses.
One more post on this matter.
I began working with BU planes in around 2005, and have road-tested planes for Lee Valley/Veritas since then. Interestingly, back then Knotts was a really vibrant forum, attended by planemakers, such as Larry Williams. He and I would have rousing debates about BU planes. His argument was that the blades could not be easily cambered. This led to my writing an article on an appropriate method, which is on my website: http://www.inthewoodshop.com/WoodworkTechniques/TheSecretToCamberinBUPlaneBlades.html
The summarised version is this: a pre-ground blade with a 38- or 50 degree bevel will have too much steel at the bevel edge to hone into a slight camber, as used for smoothing. My recommendation if only to purchase blades with a 25 degree bevel, and add the camber when honing a high secondary bevel. Easy peasy then.
Regards from Perth
Derek
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