Much has been written about the uses of a crowned, or cambered or radiused, edge on plane irons. I’m no expert on woodworking technique so I’ll leave those details to others more qualified to discuss how to put a crowned blade to best use. And much, too, has been written about how to create a crowned edge. When hand sharpening a plane blade it is almost easier to add a bit of crown than not to, especially when the honing action is diagonal or side-to-side, as it usually is when free-handing the blade on the stones. The tendency is to apply extra pressure on the corner of the blade that’s leading the way. Back and forth like that and you’ll have worn a bit more blade off of the corners – a crown is born!
Applying pressure to one corner or the other will impart a crown to the edgeCrowned, cambered or radiused edge
Honing guides are useful helpers at the sharpening bench. They can allow you to repeat a specific angle reliably, bear down hard to re-shape an edge (often eliminating the need for a powered grinder), work the tiniest micro-bevel to save time and effort and, yes, they can be employed to add a bit of crown to a blade. Most honing guides will allow some small amount of slop if you add pressure to one corner, then the other as you stroke the blade along the stones. By doing so, you’ll create a curved, crowned edge. Lee Valley even offers an aftermarket camber-roller that replaces the cylindrical roller in their MkII honing guide which makes it easy to tilt the guide as you hone. Rock and roll!
Camber roller for the Veritas MkII honing guide (in front)
Enter Dave Powell of Powell Manufacturing, the man who started DMT, the diamond abrasives experts. Dave has teamed up with Toshio Odate to make a diamond honing plate that creates a crowned blade automatically (well, not really automatically – you still have to push the blade back and forth on the plate). The plate has a longitudinal semi-cylindrical hollow shape that is 2.5 thousandths of an inch (0.0025”) deep. Honing a blade in the concave channel will put a 2.5 thou crown on the blade.
Powell's Odate Crowning plates The Odate Crowning Plate has a 0.0025" hollow
The Powell Odate Crowning Plates come in four grits: 60 micron (220-grit), 45µ (325-grit), 25µ (600-grit) and 9µ (1200-grit).
The Powell Odate Dressing plate grinds a hollow in your waterstone
After refining your new crowned edge with the 9µ plate, you use Powell’s Odate Dressing Plate, which is convex by 0.0025” to dress a hollow in one side of your 4000- and 8000-grit waterstones (Norton white and gold stones are recommended by Powell.) Now you can continue to refine and polish your crowned edge on the fine stones.
You may have noticed that it’s been a while since my last blog entry. I’ve had a lot going on and am usually reluctant to be this public about my private life but I need to share what follows. I’ll have a new blog post ready in a couple of days and it really will be about sharpening.
I am being treated for prostate cancer (don’t worry, I’ll be fine.) And my mom died (it’s okay, she was ready.)
My cancer was diagnosed very early; I have radioactive seeds implanted in said offending gland and my prognosis is excellent — I’ll be around a good long while. More about me in a bit.
Mom was 88 years old, living by herself in her own home, but trigeminal neuralgia, failing eyesight, weakening kidneys and an overall decline in strength and balance had left her very ready for the next big step. (“It’s been a good life. I’ve had enough.”) She had a hemorrhagic stroke on February 16 and died a couple hours later. Not bad at all. She was a great mom, a good friend, an adventurous world traveler and yoga instructor into her eighties. Her quick, painless passing is a sadness, not a tragedy. My sister, brother and I, along with the rest of her family and friends miss her a lot.
Beverly Balla 1921 - 2010
The topic of this Public Service Announcement is Prostate Specific Antigen (both “PSA” – clever, eh? And you thought it was about Pressure Sensitive Adhesives!), a protein produced by the prostate gland that is measurable in the blood of those of us with a prostate. PSA content in the blood tends to rise when the prostate is upset about something, be it an infection, mechanical abuse (bad bicycle seat), or cancer. Ladies, unless you want to know more about all this, please feel free to return to your woodworking blog perusal. Those of you with Y chromosomes who are up-to-date with your blood tests and doctor visits (that’s code for the digital rectal exam which is not nearly as bad as most of us imagine(d)) are likewise dismissed. But if you’re a male “of a certain age” and haven’t been getting your checkups, bend over! It may be primitive and embarrassing, but that and the blood test are the best we’ve got. Be glad someone is willing to do that for you. Do it because someone cares about you. And if you’re afraid of the exam or what you may find out, you’re just being a foolish little girly-man.
Based on my experience I’d heartily recommend a PSA test along with the physical. Do a little research and you’ll find lots of controversy about the reliability of PSA tests: that they produce too many false positives and negatives which lead to unnecessary biopsies or neglected cancers. Well, I’m here to tell you that my annual PSA test and my doctor’s concern have saved me from some very unpleasant eventualities.
Getting into more detail: first let me say that I’m 58 years old and in excellent health: good diet, proper weight, regular exercise, haven’t smoked tobacco in 35 years and quite moderate in all other things, no family history of cancer at all. Last July my routine blood-work showed that my PSA jumped from 2.87 to 4.31 in one year. Not a high number but the rapid rise was cause for concern. We tried antibiotics, hoping it was just prostatitis but finally last January decided on a biopsy that came back positive for cancer. Mine was caught so early that it was undetectable otherwise, even invisible to ultrasound. The earlier the catch the better the prognosis for survival and an early diagnosis makes one a better candidate for radioactive seed implantation, the current best treatment option (an opinion shared by many). The other treatments are external beam radiation (every day for eight weeks or so with a risk of unpleasant side effects), or surgical removal of the prostate (up to six weeks recovery with considerable risk of side effects.)
As far as I’m concerned, the seeds are the best of the bad. The implant surgery is a one-hour, out-patient procedure that left me with a sore butt for a week or so. I have 137 tiny titanium cylinders containing palladium-103 in my prostate that were inserted with 38 needles through my perineum. (I bought a Geiger-counter on eBay and sure enough, I am radioactive. You should hear that thing crackle!) The radiation irritation came on a week or two later making it hurt to pee. I’ve bitched and complained about this irritation for almost a month now, but I remind myself often that the discomfort is the effect of killing cancer. And, the discomfort I’m experiencing as I cure my cancer is nothing compared to what so many other cancer patients have to go through. Palladium-103 has a 17 day half-life so I’m already at about 25% of the original dose. I’m five weeks post-op right now and feeling better every day. Bottom line, I got lucky.
Intraoperative Fluoroscope Image of Radioactive Seed Placement
I’ve been reluctant to “come out” about this publicly. I’m not the most public person and wasn’t sure it was right to post my personal cancer story in my sharpening blog. But a friend whose advice I respect and seek said that I should post my story because so many of my readers are in the target age-group and that most of them would never read such a thing anywhere else. As I’ve been informing my friends about my condition I am dumbfounded by how many men, roughly my age have never had their prostates checked. To them and any of you who are in the same camp I say get over it! If you are of a certain age, floating on that river in Egypt and don’t go to the doctor in the next week, let me put it this way: You like living? You like sex? Peeing on demand? Get thee to a doctor! The life you save may very well, quite literally, be your own.
Okay. I’m done preaching. The next post will be in a day or two and it really will be about sharpening (Odate Crowning Plates, in fact.) But if any of you have questions or concerns that you think my experience can help with, you can find my contact info at hocktools.com and I’ll do my best to answer whatever questions you may have. I seem to have abandoned all modesty in the last few months so don’t be shy about asking personal questions about my condition or my treatment or what I’ve learned along the way. I am here for you, brothers.
The Sharpening Blog 