Memento Display Shelf

[wtnhighlander]

So, here is my latest project.  This will be used as a photo / memento / knick-knack display shelf, and will be made from white oak. The general design looks something like this, although some dimensions may change a bit as I go.  And please, don't expect frequent updates, my shop time is hit or miss right now.

 

 

As you can see, there is a repeating curve theme going on. While working this out in CAD, I determined the axes of the ellipse, one-half of which will form the curve, are 35" and 6".  To draw out this curve, I had first planned to build a "Trammel of Archimedes", similar to the one shown in this video.

 

 

However, there are problems with this approach. First, the ellipse I need is long and skinny, almost 6:1 ratio of length to width. Using a four-square base for the trammel, it becomes impractical to operate with a ratio much greater than 1.5:1, because the tracks must contain the runners at their longest travel. To get around that, I figured that I could build the base with the tracks offset toward one corner. This would allow the large ratio of length to width I needed, but only to draw 1/4 of the ellipse. Since I only need half of the ellipse anyway, my plan was to fold a sheet of paper in half and draw the 1/4 ellipse, which would create the half I needed for a pattern once it was unfolded.

 

Then I thought..."That's a lot of work".

 

Especially considering that I would probably not use such a jig again for quite some time, and don't really want it collecting dust in my tiny shop. So I took a simpler route, and used the "three points and a string method" as described here:

 

Credit to This is Carpentry for the illustration.

 

So, with a section of 1/2" plywood and some nails, I began. Sorry for the orientation, I was at the end of the bench when I shot the photo, and rotation is eluding me. Anyway, the nails are visible at the appropriate points, and I hope you can see the line drawn. This method seems to work reasonably well, but there are some important factors to getting a smooth and accurate curve:

• First, anchor the workpiece so that it can not shift while drawing. Tensioning the string takes some force.
• Second, use a non-stretch material for the string. Nylon twine is far too stretchy. The paracord shown here doesn't stretch, but is kind of stiff and a bit too thick to work easily. Something like braided fishing line might be better.
• Use anchor points (nails) that are strong enough to remain firm, even when the string rides up from the surface during the drawing action.  The finishing nails I used are almost too thin, and tried to bend inward. Yes, I nailed them right into the bench. Don't worry, the laminated SPF 2x4 bench top acts much like a self-healing cutting mat, those holes will all but vanish later.

Next is to complete the layout of this template for the curved rail, cut it out on the band saw, and refine it at my spindle sander.  For those who may not possess those machines, a jigsaw and some sand paper wrapped around a large dowel can do the trick, too.

Question for the more experienced: do you find it necessary or advantageous to seal the edges of a plywood template?  I recall Steve Duncan (wdwerker) mentioning that he liked to harden the edges of MDF templates with epoxy or CA glue, but I shouldn't need that with plywood, right?  I will eventually be running a flush-trim router bit against this.

 

 

 

[Chestnut]

This looks very interesting. I like the design however i expect no less than hourly updates.

[Chet]

1 hour ago, wtnhighlander said:

This will be used as a photo / memento / knick-knack

You left out tchotchke's and bric-a-brac.

This looks to be fun and challenging.

[Dave H]

I will defiantly be following the build, it looks to be quite interesting. But those ellipse instructions has really simplified this for me, my mother had a picture taken of my daughter when she was small maybe 3yrs old, 36 yrs ago the oval picture was printed on stretched canvas my mother wanted me to make a frame for this picture. The  frame project was quite challenging for me, I had seen the nails and string trick but finding the exact points I needed was a mystery to me I ended up using the picture of my daughter to find the out side dia. of the of the elliptical frame by scribing a line with a compass around the picture  than to find inside of the frames I couldn't use the picture anymore so I measured points off the scribed O.D. all the way around and, than used a set of French Curves to refine the shape of the frames I.D. Those ellipse instructions would have made my life so much easier and, I will save those instructions as they are the simplest explanation of the string trick I have ever seen thanks for sharing and good luck on the shelves.

[wtnhighlander]

With a few minures free for shop time tonight, I did manage to finish the layout, and cut my template free of its plywood prison.

Still needs some smoothing of the edges to make it router-bearing ready, but I'm pretty satisfied with my cut. I don't have all that much bandsaw experience under my belt. Sticking with a 1/2" blade and plenty of tension ensured a nice, square-to-the-table cut, but took some effort around the tighter parts of the curves and corners. Also, I should remember to position the saw with enough room to swing the part ANYWHERE in the plane of the table, in a radius around the blade equal to the part length. I lost count of how many times I had to stop and move the saw so the part would clear a wall.

And for those more observant of you, yes - the ends are not equal length. I just haven't trimmed them yet.

[Coop]

This is one project you won’t find me trying to replicate, and not because I don’t think it’s cool! And you won’t find me challenging you on the spelling, much less the definition of some of those words! 

This will be interesting to follow! 

[Bmac]

Great start on the templates, a definite must for this project.

What joinery do you plan to use for the shelves, esp the top and bottom shelves?

[bradpotts]

On 5/25/2021 at 9:48 AM, wtnhighlander said:

Question for the more experienced: do you find it necessary or advantageous to seal the edges of a plywood template?  I recall Steve Duncan (wdwerker) mentioning that he liked to harden the edges of MDF templates with epoxy or CA glue, but I shouldn't need that with plywood, right?  I will eventually be running a flush-trim router bit against this.

You shouldn't need it with plywood. With MDF the fibers smash where they run along the bearing and after a while it becomes a tiny bit smaller. 

This is going to be a great project. Excited to see it through. I like the complexity of the sides, it really draws your attention. Great start with the template. 

 

 

 

 

 

 

[Chestnut]

On 5/25/2021 at 10:48 AM, wtnhighlander said:

Question for the more experienced: do you find it necessary or advantageous to seal the edges of a plywood template?  I recall Steve Duncan (wdwerker) mentioning that he liked to harden the edges of MDF templates with epoxy or CA glue, but I shouldn't need that with plywood, right?  I will eventually be running a flush-trim router bit against this.

Steve used his templates for a LOT of operations so hardening the edges for him was more of a production thing. That said plywood does work a bit differently and using the template 15-20 times you shouldn't see any issues. I used plywood for my dining room chairs and they saw a good 10-12 operations and didn't have any effects.

[wtnhighlander]

11 hours ago, Bmac said:

What joinery do you plan to use for the shelves, esp the top and bottom shelves?

Not set in stone, but I think rabbeted dowel joints will be the best to assemble, and not visible. If I owned a domino, I'd use that.

[wtnhighlander]

Finished up the template in a short burst of shoptime.

First, I clamped on a pretty straight level as a fence extension. This let me trim the back edge parallel to the front.

I also parallel trimmed the end tabs.

Next, I used a file, and the Spagnuolo Special flexible sanding strip to fair out the curved edges.

Last, I slathered on a quick coat of shellac, more to help the edges sand out less splintery, than anything else. Once that dried for a few minutes, I could use the template as a gauge to determine how many pieces, and how long they must be, to glue up for a blank to saw the curved rail from. Two inch wide boards, stacked 3 deep, are perfect.

The same 2" stock will form the back, top, and bottom of these open frames. Planning on mitered corner joints, reinforced with dowels that are driven through from the sides that join the top and bottom shelf, thus hidden.

[wtnhighlander]

I spent some time gluing up shelf panels and frame blanks today.

Anyone else use painter's tape to keep steel clamp parts from staining oak in areas of squeeze-out?

Here are some of the blanks for the curved frame section.

I underestimated the amount of stock needed for these (I need seven in all), and rather that set the planer up again, I used just my saw to straighten and size these parts.

This method works well for parts that are small enough to shave each side with the saw blade. With reasonably flat rough stock, and a sled or fence extension to ensure the part is fully supported through the cut, this technique yields excellent results.

But, boy! It sure makes a mess. I think my fence is ever so slightly tighter at the rear of the blade, because there was almost no dust escaping at the front of the cut, but as soon as the material passed the rear of the blade, I was hit with a steady stream of chips.

[Chestnut]

12 hours ago, wtnhighlander said:

But, boy! It sure makes a mess. I think my fence is ever so slightly tighter at the rear of the blade, because there was almost no dust escaping at the front of the cut, but as soon as the material passed the rear of the blade, I was hit with a steady stream of chips.

I"m having that happen as well right now i swear my fence got knocked out of alignment. I really should just do a whole tune up check on my saw to make sure it's still alignmed to the miter slot as well.

[wtnhighlander]

Another short burst in tbe shop. I stuck my template to a frame blank, and bandsawed to within 1/8" or so. Then it was time to put my newest router to the test.

Can't say I'm disappointed. This is my first battery powered palm-sized router, and it worked beautifully. Easy to balance, plenty of power for the task.

I don't have a pattern bit long enough for the stock thickness, so I made one pass with the shank-bearing bit against the template, then flipped the part and did the opposite face with an end-bearing bit that referenced the earlier trimmed edge.

Worked like a champ. For the remainder, I'll use one of the bits in the table, but tonight I wanted to give the new router a workout.

Here is the template removed. I learned the hard way to clean off the carpet tape as soon as possible!

[wtnhighlander]

All the curved frame rails are now cut and routed. Still some sanding and corner cleanup to do, not to mention repairing a couple of chip-outs where routing 'uphill' wasn't avoidable. Soon, the frames will be complete, and joinery can begin!

[wtnhighlander]

A bit more work done on the curved frames today. I clamped them all together and hit 'em hard with a belt sander to smooth out any chipped edges and make the shapes as uniform as possible. I discovered that the carpet tape had managed to let the template shift slightly while routing a couple of them, but the sander brought them all back in line. Then I started the cross pieces that will join the curved rails to their opposing straight rails. I first planned to traditional frame joinery, using M&T or mitered corners. But mulling it over in my head, I realized these pieces will bear no load, only serving to space the front and back apart. The top and bottom will be glued to the upper and lower shelves, so why introduce a cross-grain part and risk unnecessary movement stress?

So, I used some leftovers to cut blocks.

With a bare minimum of glue, I rubbed the edges together until they started to tack up, then applied just enough clamp pressure to show a hint of squeeze-out, but not force the blocks to shift.

And here you can see a quick dry-fit. The cross bits have the same grain orientation as the rails, so no movement issue, AND, I didn't have to cut any joinery. Win-win!

[Coop]

This is cool!!

[Bmac]

Very nice, so you will have seven of those curved arch pieces in the display, correct? 

[Mark J]

I have to admit your logic on the horizontal pieces.  Will the structural top & bottom shelves be quartersawn to sorta match the horizontal pieces for wood movement?

[bradpotts]

This is looking great so far! I guess I didn't notice the back pieces from the design because the sides caught my attention. Thanks for the update on the router. I have wondered if they would have enough power for something like that.  

[wtnhighlander]

12 hours ago, Bmac said:

Very nice, so you will have seven of those curved arch pieces in the display, correct? 

Yes, seven. Four form the back, then 3 for ends and center.

11 hours ago, Mark J said:

I have to admit your logic on the horizontal pieces.  Will the structural top & bottom shelves be quartersawn to sorta match the horizontal pieces for wood movement?

Not quarter-sawn, but oriented so expansion is the same. Like a waterfall miter joint.

[wtnhighlander]

9 hours ago, bradpotts said:

Thanks for the update on the router. I have wondered if they would have enough power for something like that.  

That little router has plenty of power, and the battery lasts a good while. Its just much easier to run the part against a table than balance that small router base on the part.

[wtnhighlander]

Despite my complete lack of updates, I have actually put in some time on this project. All 7 frame sections are now assembled.

The shelves should go much faster....

[wtnhighlander]

I spent a few minutes marking out the dadoes that will house the middle shelves.

I am fortunate to have inherited from my late FIL, a Starret combo square with an 18" blade. Nothing else I have would span far enough (squarely) to transfer the marks from one frame to the next.

I suppose I could have shifted the frame order so that I could transfer from the straight side of each, but keeping them in assembly order helps ensure that any irregularities do not compound over multiple mark transfers.

[treeslayer]

5 hours ago, wtnhighlander said:

I spent a few minutes marking out the dadoes

looking great Ross, i would have spent an hour marking out those, but that's just me, critical cuts for sure. how do you plan to cut the dadoes ?