{"id":5767,"date":"2019-06-30T14:54:25","date_gmt":"2019-06-30T18:54:25","guid":{"rendered":"http:\/\/www.rpwoodwork.com\/blog\/?p=5767"},"modified":"2019-07-30T17:06:21","modified_gmt":"2019-07-30T21:06:21","slug":"rethinking-bed-angle-in-bevel-up-planes-part-1","status":"publish","type":"post","link":"https:\/\/www.rpwoodwork.com\/blog\/2019\/06\/30\/rethinking-bed-angle-in-bevel-up-planes-part-1\/","title":{"rendered":"Rethinking bed angle in bevel-up planes, part 1"},"content":{"rendered":"\n
\"bevel-up<\/figure>\n\n\n\n

Lee Valley and Lie-Nielsen both use a 12\u00b0 bed for their bevel-up (BU) bench planes. At least for smoothing planes, I think there are better options<\/strong>. I addressed this issue in a 2010 post<\/a> but now would like to add additional reasoning.<\/p>\n\n\n\n

Let’s start with the issue of attack angle<\/strong>.<\/p>\n\n\n\n

One of the advantages of BU planes<\/strong> is the attack angle (the angle between the wood and the leading surface of the blade) can be altered simply by changing the sharpening angle of the final microbevel. There is no need to change the frog and\/or create a large back bevel (a large bevel on the normally flat side of the blade) as with a bevel-down plane. The attack angle is a key factor in how a plane functions, especially to control tear out. <\/p>\n\n\n\n

In a bevel-up plane with a 12\u00b0 bed<\/strong>, to achieve a 50\u00b0 attack angle, a good all-around angle for a smoother<\/strong>, the sharpening angle must be 38\u00b0. (Note that all of the sharpening angles in this discussion are only the final, steepest microbevel, which is what actually interacts with the wood.) A 55\u00b0 attack, a good choice to manage most figured woods, would require a 43\u00b0 sharpening angle. A 60\u00b0 attack, which is about as steep as you can go before the plane acts more like a scraper but is nonetheless useful for difficult woods, requires a 48\u00b0 sharpening!<\/p>\n\n\n\n

Alternatively, let’s consider a 22\u00b0 bed<\/strong> for the bevel-up smoothing plane. Much lower sharpening angles can be used. For example, a 33\u00b0 sharpening angle yields a 55\u00b0 attack, which is a nice setup with an A-2 blade. The 60\u00b0 attack requires a still-manageable 38\u00b0 sharpening. On the other hand, if you want a lower attack, you could sharpen at 28\u00b0 or 30\u00b0, such as with an O-1 blade, to yield a 50-52\u00b0 attack. If slightly lower attack angles suit you, a 20\u00b0 bed is a good, versatile compromise.<\/p>\n\n\n\n

So, a 20-22\u00b0 bed angle<\/strong> in a bevel-up smoothing plane<\/strong> allows you to a create a good range of attack angles without the excessively high sharpening angles required with a 12\u00b0 bed.<\/p>\n\n\n\n

For a BU jack plane<\/strong>, the case for a steeper bed is less compelling, though still interesting. A 12\u00b0 bed with a 33\u00b0 sharpening \u2013 typical for an A-2 blade that would often be found in a jack \u2013 gives a 45\u00b0 attack, which many woodworkers consider to be a good all-around choice for a jack. Still, a 15\u00b0 bed would increase the versatility of the plane in creating slightly higher attack angles without having to increase the sharpening angle too much. <\/p>\n\n\n\n

To summarize the main point:<\/strong> a bevel-up smoothing plane with a 12\u00b0 bed requires excessively high sharpening angles to achieve the very helpful range of attack angles that is one of the key advantages to this type of plane. <\/p>\n\n\n\n

Much more to come on this topic<\/strong> in upcoming posts. Those excessively high sharpening angles produce several disadvantages. Furthermore, the lower 12\u00b0 bed is a disadvantage in itself, and actually lacks a traditionally-cited advantage.<\/p>\n","protected":false},"excerpt":{"rendered":"

Lee Valley and Lie-Nielsen both use a 12\u00b0 bed for their bevel-up (BU) bench planes. At least for smoothing planes, I think there are better options. I addressed this issue in a 2010 post but now would like to add additional reasoning. Let’s start with the issue of attack angle. One of the advantages of […]<\/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-5767","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\/5767","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=5767"}],"version-history":[{"count":15,"href":"https:\/\/www.rpwoodwork.com\/blog\/wp-json\/wp\/v2\/posts\/5767\/revisions"}],"predecessor-version":[{"id":5831,"href":"https:\/\/www.rpwoodwork.com\/blog\/wp-json\/wp\/v2\/posts\/5767\/revisions\/5831"}],"wp:attachment":[{"href":"https:\/\/www.rpwoodwork.com\/blog\/wp-json\/wp\/v2\/media?parent=5767"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.rpwoodwork.com\/blog\/wp-json\/wp\/v2\/categories?post=5767"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.rpwoodwork.com\/blog\/wp-json\/wp\/v2\/tags?post=5767"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}