Hi !
I am attempting to build a demilune table out of cherry for my wife for the foyer. What I am having difficulty in accomplishing is building a jig to bend, glue and clamp the rounded apron for the front. I have built two bending jigs to glue up the resawn strips but both do not have the proper curve. I want to make this table 42″ wide (top finished width) by approximately 16″ deep in the middle from front to back. How do I get the proper curve for the apron plus allow for the springback I will get from the apron when I remove it from the jig? I thought this would be fairly simple but I have stopped work on it for the past six months or so because the two jigs I built will make the table too small and more like a half round table. I figure I can use these jigs later for a table that is round so at least those are not a complete waste of time and material. Any suggestions would be appreciated. I did go look at the library and a Books a Million store to try to find a woodworking book on this but struck out.
Thanks in advance!
Bill
Replies
Would a gluelam type construction help prevent the springback? If so this months FWW has a method to create bent members that may work well for you.
Sorry but I did not see that as I forgot to renew my subscription(shame on me, right?). I will have to see if the issue is at the newstand. I assume that you are speaking of the March/April issue? I am missing my favorite woodworking mag.
Thanks!
You should not have any appreciable springback if your strips are thin, about 1/8 or less. Even if there is a slight springback, your should still be able to attach the apron to the top, securing it to the joinery or blocks.
Doug
Doug,
Okay, if say I resaw the strips 1/8" thick, then there shouldn't be much springback, right? I had planned on making them 5/16" thick but 1/8" won't be a problem. How then do I build the jig with a fair curve? Someone suggested a few months ago to use a nail and string to lay out a pleasing curve. I have to say that I haven't been out to the woodshop to try this yet. I plan on having an inch of the table top hanging over the apron. I have seen demilune tables built in a half round shape but the best looking ones were more ovoid in shape(if that's the proper term to describe what I have seen?). Thanks for the quick response!
Bill
I made a demi lune table recently and for the curve I took a piece of straight grained maple cut to about 1/8" by 3/4". I made a bow out of it to the curve I wanted and then traced the curve. I was only interested in the radius for the top as i was not making a curved apron. But that should not matter; a curve is a curve.
The forming jig is no big deal either when you have the curve. Take 2 pieces of 2X 8 or 2X10 depending on how much radius the apron has to have and the depth of the curve. Cut your radius and make a big U out of it and stack them so you have a form about 4" thick. Glue up the lams about 1/8" thick or so to it. Once it is set ther will be no spring back. Hope you have a lot of clamps!
Wicked Decent Woodworks
Rochester NH
" If the women dont find you handsome, they should at least find you handy........yessa!"
Edited 3/16/2005 5:40 pm ET by CHERRYJOHN
Good Deal! Thanks!
CherryJohn's technique is the way I make my curves unless I need a true arc. Good luck with your table.
Doug
B,
This thread, 19179.1 , dealt with ellipses and ovals a while back. Using 1/8" thick strips, any springback you get can be managed during glue-up to the rest of the assembly.
Regards,
Bill Arnold - Custom Woodcrafting
Click Here if you're interested in a good,inexpensive website host.
Food for Thought: The Ark was built by amateurs; the Titanic by professionals.
From one Bill to another, thanks for the info on the older thread. It answered some questions as to how to get a proper ellipse. It's been too long since I used my geometry I learned so long ago.
Why not just saw it from solid? Whether you're using three or four legs 8/4 stock should be thick enough to accommodate the curve.
Lee
Lee,
Maybe I am dense but I don't understand what you mean by "saw it from solid". The apron? I don't think you meant that at all so please make this old knothead understand. :)
Bill
That's exactly what I meant. I need solid aprons for carving so I saw it from solid. If necessary you can join pieces end to end with a deep spline and since the mitre on both pieces removes material from the back the grain is nearly perfect through the joint as long as you keep your pieces straight.You don't say how many legs you're using but 4 Is better than three because with three the center leg protrudes into a traffic area. The attachment is a demilune with 4 legs, the apron is sawn from solid 8/4 stock. See if that clears it up.LeeMontanaFest
That's some gorgeous table there! Okay, I understand what you are saying now. I had thought that with gluing up pieces end to end that makes the fair curve would expose too much end grain with the cherry making it difficult to get a uniform finish to look good. So, you spline the pieces end to end. I had seen that done before but never considered it for this table. Looks like I need to try this two different ways to see which suits me. I had planned on 4 legs because as you say, the middle leg of 3 would be in the way of traffic. With the solid wood, I might be more easily able to add that center drawer I keep considering as well. I am gettingsome very good ideas all around. Thanks Lee!
There's a pic of a table I did on this thread http://forums.taunton.com/tp-knots/messages?msg=20211.4 It's more of the semi-circle variety that you mentioned. I did this with 1/8 cherry slices and used MDF to make male/female glue lam forms. You can get a curve laid out to your liking and make a template to cut the MDF and glue it up as thick as you need. You do need to account for the thickness of your apron when you make the template or forms so that the male/female parts come out right. I used urea resin glue and didn't get any springback worth measuring. One thing I didnt do when I made my forms that in hindsight would have been better - I'd glue/screw some square stock on the bottom face of the forms so that when you slide the halves together they work as guide rails to keep the forms aligned. I managed to wrestle all my forms and parts together OK but it would have been easier with something to keep the forms from wanting to slide side to side.
If you build it - he will come.
Another stunning table! That open gridding had to be harrowing to do but it looks as if it was well worth the effort. I may just have to readjust my drawings to take a few of the ideas I have learned tonight and put them to use on this table. Thank you!
What I have done in the past is just draw it out full-scale and either make a paper template or just build my form on top of the drawing. This also helps figure out joinery angles/issues. I just hand-draw what looks right and use a thin ripper to fair the curve and go from there. What pleases the eye isn't necessarily going to be a perfect geometric shape in my opinion.
Glue lam should work fine, but you might think about soaking or steaming the laminations if its a tight bend or if the material isn't bend friendly. Leave the lam's in the form overnight so they take the set and then let them dry for a day before you do the glue up.
But you should be able to do it without the steam or soak if the lam's are 1/8 cherry and you have seven or so laminations. I've done dozens of chair parts this way and had very little if any spring back.
You can also just do the bending form using station angles with 1/8" hardboard facing attached. Be sure to use more hardboard between the lams and the clamp blocks when you do the glue up. Helps to have clamp blocks that help even out the pressure, I made mine with 1/4" cork and 3/4 ply scrap. And use some method to keep from gluing the lamination to your form or surface. I just put shipping tape on the surface where the lam's would be.
Better yet would be to use a vacuum bag for clamping but thats a significant investment time and money-wise.
With this method you have the necessary jig material to do other shapes since you can take the assembly apart and re-use the angle stations and clamp blocks. I'll attach a photo of a desk apron setup that used this arrangement, maybe that will make it clearer.
Good luck,
-Mario
This forum post is now archived. Commenting has been disabled