Screwy stretcher frames

KingstonFineArt

Have you notice how stretchers are these days. I've had to send several batches back because they were so bent and twisted. A couple of months ago I way building a 3 by 4 foot canvas when the figure joint broke on the long side. I don't like painting on big panels. I like the resistance of a canvas. The time it took to have the stretcher swapped I forgot what I was going to paint. 

I don't like big panels. I've made strainer frames, stretchers without keyways, they can't be made taught enough. 

Does anyone know about buying a jig to cut keyways.

GTO

I have the same problem with a large stretched canvas on those cheap stretcher bars.  Ugh.
I need to make another canvas and I’m thinking of using a table saw to cut some existing bars shorter.  Back in college days we used brick molding to make stretcher bars for large canvases.

KingstonFineArt

@GTO
I think I may have an idea how to make a jig for my inky little table saw. I'll draw it up in CAD. Might take a few iterations.

GTO

@KingstonFineArt post your approach if you can.  I’m probably going to cut mine on Sunday.  I don’t have a good solution (yet anyway) on doing the keys.

KingstonFineArt

@GTO

I've worked out the basic process. There are 3 cuts on each end. There's left and right ends. Need a  sled with 3 jigs positions for each end. Making the jigs would take some trail and error.

Thee pattern is one I use for strainers. Two pieces of 1 3/4 x 1 1/2 stock screwed togetherVery sturdy. But not adjustment.
 
At least now I understand how to do it. But you wouldn't want to do this for just one set of stretchers.

Over the next few weeks as the weather breaks I'l build a sled and a base jig. My shop is in an unheated shed.

GTO

@KingstonFineArt I looked at a set this morning and yeah it doesn’t make sense to do that for one set.  The jig is the way to go.  

KingstonFineArt

I made full size models of right and left ends to fit out jigs. This is uncharted territory it may take a while.

The wooden strainers that I have made shown here are two pieces screwed together. The grain of the wood opposed making for less warping and twisting. My hope is to figure out how to add the millwork.

GTO

Did you 3D print those jigs?  I’m not an experienced wood worker and would like to see how you use them to make the bars.
yesterday I setup a sacrificial fence for a chop saw so that I can make some simple shadow box frames.  (I will cut the frame material in a table saw and use the chop saw to cut them to length)

One of the things I wonder about is if there is a trick to making accurate cuts so that when you put the frame together the corners match up tight.  I’m thinking if the chop saw is off by a degree or so that would throw things off.  

Another thing I am thinking is to use India ink to “ebonize” the wood and get a nice dark look to it without using black paint which could look a bit “manufactured”.

KingstonFineArt

@GTO
It depends whether the chop saw is single action. Like mine. Keeping things tight and useing super straight stock. Will help. Oh and patience.

These plastic things a just to set up jigs. And this will only work for these big stretchers. This is all set up in CAD so scaling is easy. I'd like to find a millwork supplier that has custom profiles for stretchers.