dan Posted March 27, 2007 Share Posted March 27, 2007 I am working on a desing to build a chair that requires to bend some of the rod in a specific pattern. I see that i could build a fork to for my hardie hole but How precise can i get with this tool? if I need to make a few of the exact same shape i am affraid that it will be hard to duplicate. Any suggestion on how to systematically re create the same bend or shape? Dan Quote Link to comment Share on other sites More sharing options...
Mills Posted March 27, 2007 Share Posted March 27, 2007 First thing I do is do a full size sketch on craft paper. office supply or packing supply should have it. for bending what I have done to accomplish this is to buy a harbor freight bender. please no groaning from the audience. You can then make nice smooth repeatable bends (with practice). That is only the start though. you will need some bending forks and a way of supporting your work. do you have a way of anchoring some angle iron to something so that you can pull and push against it? I have a piece of 2 ft square 3/4" plate that I can weld to. make a bending fork oput of some suitable med carbon steel and heat treat it. 4140 is nice stuff to work with as is grader blade. You will need a couple of sizes of forks to work different radi. 1 should be large enough to to go over the stock and the angle iron brace then you can use another fork to put it in the right place. Every so often place the piece on your full size drawing to check for accuracy. The first is pretty quick, the second takes about three times as long cause you are learning to match the curves. After the second one you should start to get the feel for it and the pace will pick up. That is the best I have. Quote Link to comment Share on other sites More sharing options...
johnny99 Posted March 27, 2007 Share Posted March 27, 2007 Hi Dan. I agree about the full size drawing. To answer your question, yes you can make repeat bends w/bending forks. It takes a fair amount of practice to do it quickly and accuratelly though. I.e. No kinks. I usually draw the element full size on a welding table, then hand form 3/8x 1 1/2" FB. into jigs that match the tricky parts of the drawing,(radius,scroll,loops,etc...) and weld them directly to the table. Be careful to leave clearance around jigs to swing the material. Edit: I don't mean that you should weld the jigs onto the drawing ,like you were going to bend a whole pattern in one go. This ussually results in clearance issues, and your piece cooling and cinching onto the jig. Just weld the jigs at oppossite corners of the table or whatever and match the parts up to the drawing piece by piece. I do work like this hot. But the jigs I use would certainly stand up to bending this stuff cold, you would have to allow for springback though. Hope this helps John Quote Link to comment Share on other sites More sharing options...
ThomasPowers Posted March 27, 2007 Share Posted March 27, 2007 Tight curves: use a bender. Long sinuous curves jigs welded to a steel table and you may need to make a long forge to get a long length hot to bend. Quote Link to comment Share on other sites More sharing options...
Glenn Posted March 27, 2007 Share Posted March 27, 2007 For building "A" (read one) of anything, go with bending forks and a full size pattern. When you get to duplicate bends, or duplicate elements you may want to think of building a jig. With practice one is about as fast as the other. If you plan on building a dozen chairs (or many many duplicate parts) then full size jigs for all parts speed up the process. This is not taking away from the traditional blacksmithing as you can still hand forge the ends, hand forge the stock for texture, use hand built decorative collars, etc., to give it a non-fabricated look. Quote Link to comment Share on other sites More sharing options...
dan Posted March 27, 2007 Author Share Posted March 27, 2007 Thank you all for your input. I guess the full size Jig is a good idea as well as the fork. Back to basic... Practice makes you perfect. Thank again Dan Quote Link to comment Share on other sites More sharing options...
johnny99 Posted March 27, 2007 Share Posted March 27, 2007 Dan. generally when doing jigs,I will actually weld them to a piece of scrap plate and then tack that to the table so that when you cut it loose there is less damage to the table, and the jig is still usable. Don't forget to make one extra part for each jig, and wire them together so that in 5 years when someone wants one more, you can find the right jigs in the pile. Quote Link to comment Share on other sites More sharing options...
Blacksmith Jim Posted March 31, 2007 Share Posted March 31, 2007 If you weld a piece of angle to the bottom of a jig you can just clamp it in a vise. Quote Link to comment Share on other sites More sharing options...
Glenn Posted March 31, 2007 Share Posted March 31, 2007 A quick search of IForgeIron Blueprints returned the following: BP0121 Vise Bending Forks BP0123 Bending Fork BP0257 Bending Forks BP0285 Bending Forks BP0290 Bending Forks Quote Link to comment Share on other sites More sharing options...
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