Hello! First question on the forum–I’m just learning about woodworking and starting to buy and tune up tools.
Okay so I just bought a used Stanley #9 1/2 block plane. With my other tools, I’ve been hollow grinding and then freehand honing but I notice that the old blade that was in this plane has a really shallow bevel angle. I was taught never to hollow grind all the way to the edge because it can chip and weaken the blade (is that right?). But if I bring the blade to the grinder with the tool rest set at a steeper angle, the grinder will start grinding right at the edge. How do I increase the bevel angle? I’m worried about ending up with a rounded bevel if I try to freehand it, and I’m worried about damaging the blade if I take it to the grinder.
Thank you very very much!
Replies
Keep cool
I hollow grind and freehand hone everything, including #9 1/2 blades. Hollow grinding to the edge is not a problem IF you keep the blade cool. On a 3600 rpm grinder this can be very difficult. Soaking the blade in ice water before and during grinding helps, as does using a friable wheel. Stop and cool the blade before you get discoloration. Practice on a old chisel or a crappy #110 blade first. Slow speed and water cooled grinders help greatly. I lucked out and picked up a Tormek on super clearance.
You can also use a belt sander. It will run cooler, but it is still important to stop and cool down the blade. --Important safety tip-- be careful where the sparks go.
If grinding/sanding doesn't work or you are too nervous to try it, break down and get a honing guide:)
Oh . . . nowwww . . . no reason to fire up all that grind grind
Just hone a steeper small bevel on the edge of your shallow angle and go to work cutting wood.
Use a sharpening jig such as the Veritas Mk II. Yes I can sharpen by hand but an exact blade geometry (a flat facet at the edge as opposed to a sloppy, rounded area with a sharp edge) will cut deeper, better, longer. ESPECIALLY in the ultra hard woods such as bubinga , purple heart, etc.
The only time I would power grind is to LOWER the angle of the bevel ; say I have a 45° beveled blade and I need a 35° angle.
PS: Here is THEEEE definitive article for tuning up that block plane and one of the best explanations of how a plane needs to be set up, how it works and why. A gem of an article.
https://www.finewoodworking.com/how-to/article/souping-up-the-block-plane.aspx
PPS: The reason for avoiding grinding to the edge is not chipping. The problem is the power grinder heating the blade, which can happen in the blink of an eye on the the thin edge, to the point the oil or water quenched hardness is lost.
For example the maker of the blade heated the edge red hot and instantly chilled it in oil or water to cause the grain of the metal to stop moving. Like taking a snap shot of the grain at a certain state of change caused by the heat.
If the blade is heated again it can cause this hard state to change back to a softer state.
That is a very simplified explanation and doesn't address anealing but if you heat the blade on the grinder to a temp even far bellow red heat you will be OVER anealing the blade and the hardness will more or less be lost.
They sure are easy to hone then but they don't hold an edge.
Thank you!
Thank you both very much! Good to know about overheating and how to avoid it. I'll buy a guide first thing tomorrow. Seems like correct blade geometry is the most important thing, so that I can just get to work making, and I'll keep practicing freehand in the meantime. Also, thank you for the article, Roc. So, so interesting and helpful. Good to be able to keep working. Thanks.
Cheers
Railroad,
If you can find time post some photos of what you are making. Even early stages of the projects.
That would be great to see.
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