{"id":710,"date":"2013-01-19T22:53:56","date_gmt":"2013-01-20T03:53:56","guid":{"rendered":"http:\/\/jmillerid.com\/wordpress\/?p=710"},"modified":"2013-01-19T22:53:57","modified_gmt":"2013-01-20T03:53:57","slug":"diy-tube-bending-tool","status":"publish","type":"post","link":"https:\/\/www.jmillerid.com\/wordpress\/2013\/01\/diy-tube-bending-tool\/","title":{"rendered":"DIY tube-bending tool"},"content":{"rendered":"

My plans for the milling machine oiling system<\/a> call for some small-diameter bent brass tubing. I looked into the various tools designed for this, but the high end is too expensive and the low end looks pretty cheesy. I also wanted a small bend radius, which is hard to come by in off the shelf tools. It seemed easy enough to design a simple bending tool, and besides there’s nothing I like better than making stuff that makes other stuff.<\/p>\n

My tubing has a 3\/16″ OD and I was aiming for a 3\/8″ bend radius (to the centerline of the tubing). I only anticipate needing 90 degree bends, but it didn’t seem any harder to allow for 180 degree bends. With these parameters I modeled up a simple design in CAD and ordered a few pieces of brass and steel from onlinemetals<\/a>.<\/p>\n

The first step was to grind a lathe tool blank to a 3\/16″ diameter half-round shape. With this I turned some 3\/4″ brass round rod into a set of rollers that closely fit the 3\/16″ tubing.<\/p>\n

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I then milled the end of a 4″ length of 9\/16″ square brass bar to accept the smaller roller, and drilled it for a tight fit to a 1\/4″ dowel pin (1″ long).<\/p>\n

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I then drilled two 12″ lengths of 1\/8″ x 3\/4″ mild steel to accept the two rollers and welded two more shorter lengths of steel to create a rectangular tube handle. Done and done!<\/p>\n

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The square brass bar is clamped into the vise, and the tube to be bent is gently clamped to the brass bar with a rubber-jawed clamp.\u00a0The first test worked perfectly!<\/p>\n

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The bends aren’t perfect– there’s a small amount of collapsing, probably from the small bend radius and the imperfect roller profiles. But I sawed through one of the bends at the thinnest part to see how much collapsing there was, and I think it’s acceptable for my needs.<\/p>\n

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Here is the collapsed section (top) next to the normal tube section for comparison. Not bad!<\/p>\n

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Next step: experiments in brass soldering.<\/p>\n","protected":false},"excerpt":{"rendered":"

My plans for the milling machine oiling system call for some small-diameter bent brass tubing. I looked into the various tools designed for this, but the high end is too expensive and the low end looks pretty cheesy. I also wanted a small bend radius, which is hard to come by in off the shelf […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[38],"tags":[53,34,54,16],"_links":{"self":[{"href":"https:\/\/www.jmillerid.com\/wordpress\/wp-json\/wp\/v2\/posts\/710"}],"collection":[{"href":"https:\/\/www.jmillerid.com\/wordpress\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.jmillerid.com\/wordpress\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.jmillerid.com\/wordpress\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.jmillerid.com\/wordpress\/wp-json\/wp\/v2\/comments?post=710"}],"version-history":[{"count":8,"href":"https:\/\/www.jmillerid.com\/wordpress\/wp-json\/wp\/v2\/posts\/710\/revisions"}],"predecessor-version":[{"id":726,"href":"https:\/\/www.jmillerid.com\/wordpress\/wp-json\/wp\/v2\/posts\/710\/revisions\/726"}],"wp:attachment":[{"href":"https:\/\/www.jmillerid.com\/wordpress\/wp-json\/wp\/v2\/media?parent=710"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.jmillerid.com\/wordpress\/wp-json\/wp\/v2\/categories?post=710"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.jmillerid.com\/wordpress\/wp-json\/wp\/v2\/tags?post=710"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}