{"id":5860,"date":"2019-07-30T22:27:47","date_gmt":"2019-07-31T02:27:47","guid":{"rendered":"http:\/\/www.rpwoodwork.com\/blog\/?p=5860"},"modified":"2019-07-30T22:27:47","modified_gmt":"2019-07-31T02:27:47","slug":"rethinking-bed-angle-in-bevel-up-planes-part-3","status":"publish","type":"post","link":"https:\/\/www.rpwoodwork.com\/blog\/2019\/07\/30\/rethinking-bed-angle-in-bevel-up-planes-part-3\/","title":{"rendered":"Rethinking bed angle in bevel-up planes, part 3"},"content":{"rendered":"\n
\"bevel-up<\/figure>\n\n\n\n

To create higher attack angles, such as 55\u00b0, to reduce tearout with a bevel-up smoothing plane, here are more advantages to a 20-22\u00b0 bed angle versus the commonly produced 12\u00b0 bed angle. <\/p>\n\n\n\n

1. A higher bed angle requires less camber in the edge to achieve a given “functional camber.” Please see my post<\/a> that defines the terms I am using and explains the simple math, and this post<\/a> that shows the effect of bed angle. A blade placed in a 12\u00b0 bed requires about 75% more “observed camber” to achieve the same functional camber<\/strong> as when placed in a 22\u00b0 bed. For example: you must grind .014″ camber to achieve .003″ functional camber in a 12\u00b0 bed, but only have to grind .008″ to achieve the same .003″ functional camber in a 22\u00b0 bed. <\/p>\n\n\n\n

Putting camber in the blade edge takes time and it’s easier to do if there’s less of it.<\/p>\n\n\n\n

2. As the wear bevel develops on the lower (flat) side of the blade, an adequate clearance angle<\/strong> is maintained longer when the bed angle is greater. Again, I reference<\/strong> Terry Gordon’s article in Furniture and Cabinetmaking magazine (November 2018, Issue 276, pp. 48-50) and Brent Beach’s website<\/a>.<\/p>\n\n\n\n

Here are two more possible advantages<\/strong> to a 20-22\u00b0 bed versus a 12\u00b0 bed, but these are speculative.<\/p>\n\n\n\n

1. For a given attack angle, the narrower sharpening angle (as would be used with the higher bed angle) may produce less resistance<\/strong> in the cut. I’m not sure. Maybe resistance is instead determined only by the attack angle, as has been suggested to me by a planemaker. I do not have a way in my shop of making an apples-to-apples comparison. I’d need two planes, identical except for bed angle, then make the same attack angle in each \u2013 for example, one with a 22\u00b0 bed and a 33\u00b0 blade (=55\u00b0) and the other with a 12\u00b0 bed and a 43\u00b0 blade (=55\u00b0).  <\/p>\n\n\n\n

2. Perhaps the steeper 20-22\u00b0 bed is an advantage in design and manufacturing<\/strong> in that it is sturdier and less likely than a 12\u00b0 bed to deflect downward. I don’t make planes, so I don’t know.<\/p>\n\n\n\n

Coming up:<\/strong> just a few more points.<\/p>\n","protected":false},"excerpt":{"rendered":"

To create higher attack angles, such as 55\u00b0, to reduce tearout with a bevel-up smoothing plane, here are more advantages to a 20-22\u00b0 bed angle versus the commonly produced 12\u00b0 bed angle.  1. A higher bed angle requires less camber in the edge to achieve a given “functional camber.” Please see my post that defines […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[6],"tags":[40],"class_list":["post-5860","post","type-post","status-publish","format-standard","hentry","category-tools-and-shop","tag-bevel-up-plane-design"],"_links":{"self":[{"href":"https:\/\/www.rpwoodwork.com\/blog\/wp-json\/wp\/v2\/posts\/5860","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.rpwoodwork.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.rpwoodwork.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.rpwoodwork.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.rpwoodwork.com\/blog\/wp-json\/wp\/v2\/comments?post=5860"}],"version-history":[{"count":21,"href":"https:\/\/www.rpwoodwork.com\/blog\/wp-json\/wp\/v2\/posts\/5860\/revisions"}],"predecessor-version":[{"id":5890,"href":"https:\/\/www.rpwoodwork.com\/blog\/wp-json\/wp\/v2\/posts\/5860\/revisions\/5890"}],"wp:attachment":[{"href":"https:\/\/www.rpwoodwork.com\/blog\/wp-json\/wp\/v2\/media?parent=5860"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.rpwoodwork.com\/blog\/wp-json\/wp\/v2\/categories?post=5860"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.rpwoodwork.com\/blog\/wp-json\/wp\/v2\/tags?post=5860"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}