How do you create smooth curves between the legs, seen on some mission style furniture?
I intend to build a bathroom vanity in that style, something akin to a sideboard. It will be 66″ by 20″. The height will be only about 27″ upon which will sit vessels. It will have two doors under the “sinks” with drawers in the middle. It will have 8 legs.
I want it to stand on legs, hence my question. From watching David Marks on the DIY channel he would create a template out of MDF and then use that with a flush trim router bit. But I’m still not sure how to create a smooth flowing arc between the legs, either on the MDF or the final material.
Hastings
Replies
I'm a newbie, and I've never done it, and I didn't stay in a Holiday Inn last night.
BUT -- you have three options. One, make a jumbo-sized compass out of scraps and put the pivot at the center of the arc, and a marking device in the other and mark the arc. Depending on the size, this may or may not be practical.
Second, is to make an oversized "V" apparatus that is made out of scraps with a pivot at the apex, and also has the marker at the apex. Put pins at the ends of the arc. Estimate how far you want the arc to be above the straight line between those pins should be and put the marker on that spot-- just eyball it. Then spread the legs of the "V" until both are touching the pins and lock down the "V" so the angle won't change. Then just mark the line from one pin to the other, keeping the legs of the "V" touching both pins at all times. This is easier to do than it is to describe, and I did see David Marks do it on one of his recent DIY shows.
NOW - the easiest and what will work the best for your application is to just use a flexible stick. Put pins at the end of the arc, and a third pin in the midpoint of the arc, and moved out to where you want the high-point in the arc to be. Put the flexible stick against the three pins -- it will trace out a smooth curve. Mark along that stick and you are done. The stick can be a thin piece of wood or moulding, a long flexible aluminum rule or yardstick, a batten out of your sailboat mainsail, anything that is stiff enough to warp into a smooth curve, but flexible enough that it is easily bent into shape.
After you mark the MDF, then of course you need to cut it out using a bandsaw or saber saw, sand it to the line very precisely, etc.
Hope this helps.
-Tom H. Ventura, CA
I actually bought one of these gismos from Lee Valley, which works very well:
http://tinyurl.com/2dje4u
However, theirs is 4', and I have used the same principle to make several of my own in smaller sizes, using 1/4" X 3/4" oak or maple stock -- a slit on each end of the stick with a knotted string to establish the size of the arc.
Low tech, but effective.
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"It is what we learn after we think we know it all, that counts."
John Wooden 1910-
Hi Hastings ,
For only a few what I do is make a half template usually out of 1/4" material , then flip it over and draw the full arch on your actual part .
I cut it out on the Band Saw and sand it to the line on the edge sander , you could also use a Jig Saw and a drill press drum sander or your belt sander on edge .
Making a template to use your router with a flush trimmer bit will produce accurate curves but I can make the actual parts needed my way in about the same time it may take you just to make the router template and for the most part as accurate as needed .
good luck dusty
Thank you for the ideas. The LV jig looks like it would work as no single span is over 4'.Thank you again for the advice; I've got enough to do it now.Regards,Hastings
To Hastings-
My preference is a band saw and a spokeshave. The smallish sole of the shave will knock down the high spots and create a smooth curve.
Router and trammel work great also.
I think David Marks cuts a template out of MDF, and then uses a flexible sanding block to smooth the curve, then clamps the template to the finished piece after rough cutting it, then uses a router with a flush cutting bit to match it to the pattern, then edge sands it, then cusses because he forgot to cut the joinery before cutting the curve( oh wait, that was me ). It is alot of extra work. This is one area hand tool skills pay serious dividends.
Regards, Sean
"then cusses because he forgot to cut the joinery before cutting the curve( oh wait, that was me )."LOL!Not a problem if you have a Domino!I always thought Marks' approach was a bit laborious.Thank you for sharing your perspective.Hastings
I like to make my templates out of Plexiglass (acrylic). I get scraps and shards at a plastics manufacturer/retailer.Then, use the flexible batten to mark the cut. Cut it on a bandsaw as close to the line as you can. Then sand it smooth. If there are nicks which go beyond the line, use acrylic called Duralay, you get it at a Dental Supply House, mix up the powder and liquid, apply it to the error. After it is set, just use sandpaper to fair it up.
Stef
I'm assuming you need a method to draw an arc. See above for ways to cut it out and smooth.
For a simple arc without having a super large beam (needed for shallow arcs of large radius):
Method 1:
* Put a nail at each end of the arc and at the midpoint.
* Get some straight scrap wood and put one from one end to the midpoint nail, Position the other beam parallel to the chord (base), fasten by whatever means you wish (butt miter, half lap, etc.). Allow the glue to cure.
* Put a pencil in the apex, and keeping each arm on its respective nail, trace out half the arc.
* Reposition on the other side and repeat.
Method 2:
* Same three nail positions.
* Take two beams and fasten them as above with a V with the left beam on the left nail, the right beam on the right nail, and the apex at the center nail.
* After the glue cures, remove the center nail, put a pencil in the apex, and keeping both beams in contact with their respective nails, trace the arc. If the angle is 90 degrees, the result will be a half circle, more than 90 degrees, part of a semi-circle.
The advantage with the Method 1 is that it needs shorter beam lengths.
But I'm still not sure how to create a smooth flowing arc between the legs, either on the MDF or the final material.
This way is the easiest for me. I make smooth templates directly with the router; no fuss, no drawing, no sanding. It works especially well where the ar is very shalow, and the radius can get very large (>30' in one of the examples shown):
http://forums.taunton.com/n/find/findRedir.asp?webtag=fw-knots&mg=CCA968C4-0D15-4EA1-BC87-527B1457ADA9
Barry:Thank you for drawing my attention to the methods you use for creating long-radius arcs. Presumably your outrigger boards (the ones with the grooves) are set at Theta 3, which is derived from theta 1, which, in turn, establishes the desired arc?It loks very ingenious, but I quite like the pinned metal band for its simplicity; but I am curious as to why you don't think that the results are very good using this method.Regards,Hastings
Thank you for drawing my attention to the methods you use for creating long-radius arcs. Presumably your outrigger boards (the ones with the grooves) are set at Theta 3, which is derived from theta 1, which, in turn, establishes the desired arc?
Correct.
It loks very ingenious, but I quite like the pinned metal band for its simplicity; but I am curious as to why you don't think that the results are very good using this method.
IMHO, it's a false simplicity. OK, you bend the stick and that gives you a curve. Then you need to carefully trace the curve on to the template material, and faithfully follow the shape without bending the stick further an distorting the shape. Then after rough-cutting on the bandsaw, you need to spend alot of time sanding/filing the rough curve on the template in order to make it smooth and usable.
It's that sanding/file time, which is tedious, not fun, and error-prone, that I wanted to eliminate.
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