Repeatable curve in wood |
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MattStolton
Old Croc Joined: 04 September 2010 Location: Walthamstow Status: Offline Points: 4234 |
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Posted: 18 April 2017 at 12:37pm |
I want to redesign my hi-fi mid top boxes, so looking for aesthetic as well as sound!
Rather than just a cubic box, I fancy going a bit curvy to the sides. I am happy to laminate up thin sheets to achieve this. However, I am stuck in forming the actual curves. So, I need to put identical curves (not radiuses, some form of "aerofoil" shape) on the bottom and top of my box, but also the same curve on a couple of braces. Imagine the normal rectangle for a bottom and top of a box, but sides are curved. As per this - how do I form the MDF top and bottom panels, with a consistent curve, repeatable enough to make minimum 4 panels (2 tops, 2 bottoms, for a stereo pair, and probably a few more to form braces) I haven't got a band saw, or CNC, so how do I go about creating a consistent curve (both LHS and RHS the same) to cut out multiple pieces. I have a decent 10" table saw and router, but stuck how to get a machined consistency to the curve, that is repeatable to cut both LHS and RHS I reckon hand sawing, or even jigsaw, will not be repeatable enough or accurate Answers on back of postcard, etc....
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Matt Stolton - Technical Director (!!!) - Wilding Sound Ltd
"Sparkius metiretur vestra" - "Meter Your Mains" |
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Panda
Registered User Joined: 01 November 2010 Location: Cape Town Status: Offline Points: 46 |
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Here is how I would do it in the absence of the CnC etc. To get accurate curves you can always use sketchup or other cad / vector freeware to create a printable scale shape to trace. Draw / trace accurate pencil lines onto a spare piece of MDF. Rough cut with a jigsaw and carefully make a template by sanding to the line with a (friends) belt sander. You now have a template that you can rout more copies around with a flush trim bearing router bit. Even if not totally perfect you can be sure that each copy will be the same as the template! Edited by Panda - 18 April 2017 at 1:02pm |
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bob4
Old Croc Joined: 29 February 2004 Location: Finland/Germany Status: Offline Points: 1842 |
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assuming you want a symmetrical shape, you would need to make only one router jig with the desired curve/shape. Simply flip the jig or the panel to do the second curve
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colinmono
Young Croc Joined: 10 October 2007 Location: Midlands UK Status: Offline Points: 1111 |
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I used a FISCH Flexi Curve (from Axminster) recently to cut some curves with a router, worked well for me. Not cheap, but I didn't have a belt sander and hand sanding curves to make a template sounded like a pain in the proverbial.
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toastyghost
The 10,000 Points Club Joined: 09 January 2007 Location: Manchester Status: Offline Points: 10920 |
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MarjanM
Old Croc Joined: 10 February 2005 Location: Macedonia Status: Offline Points: 7810 |
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Find a local cnc place. Cut one template and do the rest with a router.
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Marjan Milosevic
MM-Acoustics www.mm-acoustics.com https://www.facebook.com/pages/MM-Acoustics/608901282527713 |
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MattStolton
Old Croc Joined: 04 September 2010 Location: Walthamstow Status: Offline Points: 4234 |
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Wow. Insane. I have seen someone do layers of 1" ply, layered up to make the side walls, but not from individual plys!
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Matt Stolton - Technical Director (!!!) - Wilding Sound Ltd
"Sparkius metiretur vestra" - "Meter Your Mains" |
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odc04r
Old Croc Joined: 12 July 2006 Location: Sarfampton Status: Offline Points: 5483 |
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As someone else said, jigsaw/cnc the template. Adjust till you are happy vs a printout or whatever. Then use flush trimming bits to make a whole bunch and form the sides against them.
Made some curved spice rack sides like this a few years back, still got the jig that I used to create identical pieces as opposed to trying to cut out no 2. same as the first. Worked perfectly. |
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MattStolton
Old Croc Joined: 04 September 2010 Location: Walthamstow Status: Offline Points: 4234 |
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OK, so spend 2 days making the perfect jig, to save 1 day of free hand cuts!
I just wondered if I had missed something obvious, but looks I will make a jig up, to router the panels up then. MDF worthy enough to make jig from? Shouldn't wear from doing a short fun of panels?
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Matt Stolton - Technical Director (!!!) - Wilding Sound Ltd
"Sparkius metiretur vestra" - "Meter Your Mains" |
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SouthwestCNC
Young Croc Joined: 27 November 2015 Status: Offline Points: 830 |
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Trial and error I'm afraid, Laminated curves will always spring back slightly. I would begin by creating a former made up of multiple templates spaced equally apart until youre at the same height as the panel you want to make (ideally spaced the same distance as the thickness of the template) Make the templates with excess width so they can be reworked to alter the curve if need be. I would start with a curve that ends 5-6mm tighter than you want it to be. Laminate your sheets togther and use a vacuum bag and pump to clamp to former. make sure you use breather material from the bag hose entry point across the length of the former to the opposing side. Repeatability with this method is good. You may just find yourself cutting your top and bottom panels to the curve it creates.
Make one template and use a flush router to make others. Need to use 18mm ply with a vac bag really. Edited by SouthwestCNC - 18 April 2017 at 3:40pm |
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SouthwestCNC
Young Croc Joined: 27 November 2015 Status: Offline Points: 830 |
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Just reread the brief ^ this may be a bit ott just for 4. MDF will work for a few. If you make a former for the outside of the curve as well you can hinge the two formers and just clamp instead of a bag.
Print the curve on paper and stick it to the template will give you a line to follow. But to me you are working backwards. You make the curve panel and then cut the top and bottom panels to suit. Edited by SouthwestCNC - 18 April 2017 at 5:36pm |
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SamV
Old Croc Joined: 21 October 2008 Location: London Status: Offline Points: 8707 |
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Draw/sketch onto perspex, cut out using a scroll saw/jigsaw/sharp blade, hand sand down, use a bearing guided router.
Wanna borrow my ancient scrollsaw? I'll dig it out and see if it's still working.
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