Wastebasket – #5 Index Guide & Jig Testing

Probably the most critical item in the jig is the Index Guide or bolt.  The diameter of the bolt that interacts with the jig has to match the thickness of the saw cut.  It’s this match that allows the jig to make perfectly matching box joints.  Now the dado blade setup has two stacked 1/8” blades for  ¼” plus a .004” spacer totaling .254” so the bolt diameter that works the jig needs to be that.  Fine tuning will come later after the first test cut.  This means the 5/16” diameter bolt needs about the last half inch or so thinned down to match the thickness of the dado stack.  You would think that would be the dado thickness of ¼” plus .004” or .254”.  Not so, when I cut a wood spacer to fit the cut the dado stack made it came to be .247” so that’s what I need.  As a side note my guess is over the years when I have had the blades sharpened it may have reduced the total width of the cut some.  Anyway, the left photo is the bolt ready to go in my lathe chuck so I could file it down to the desired diameter.  The three nuts on the bolt will help keep it stable in the chuck.  The right photo is after it has been filed down to .248” which is a little large but that’s my starting point for testing.  The two extra nuts on the bolt in the right photo are my stop to keep from filing too far up the bolt.

Installing the bolt in the Moving Indexer is next.  In these photos the bolt has been run in with the lock washer and nut installed. 

The redesign in going from the wood spacer to the bolt requires one more change.  Since the nut is a larger diameter than the bolt, I need to cut a clearance notch in the upper right part of the right corner of the Side Brace piece.  The top and the lower left photos show the notch where I used a Japanese pull saw to make the relief cuts.  The lower right photo shows the finished notch after the waste was removed and the bottom cleaned up.

With the notch completed the Moving Indexer assembly is put back on the jig and slid all the way to the right until the bolt contacts the right Side Brace.  The two photos show clearance around the nut from the both inside and outside the jig. 

Cutting all 53 Spacers for jig is next.  The top drawing shows what I think their setup will be for cutting alternating ½” and 1” finger joints.  The middle photo has all of them cut and ready to go into the jig.  The bottom photo has the Spacers in the jig for even ½” joints which is what I will start testing with.

Actually, cutting the Spacers is straightforward.  A piece of ½” thick MDF is cut into strips using the table saw as in the top photo.  They are then cut to length using the chop saw with a stop set shown in the bottom photo.

Next is to install the stack dado and start the calibration of the jig.  Below are the left and right 1/8” thick outer blades of the 8” dado.  Also shown are two of the ten shims in several sizes that can go between the blades to fine tune the width of the cut.  The top one is .004” thick and the bottom one is .020” thick.  Here I will only be using the .004” one.

The last piece is to be installed is the Vertical Indexer (red arrow).  To locate it the bolt in the Moving Indexer is pushed up against jig’s right Side Brace (left bottom photo).  A spacer the thickness of the blade stack (.247”) is inserted in the slot it cut in the jig’s Base then the Vertical Indexer is set against it and screwed in place making sure it’s square to the base (right bottom photo).

At long last I can make my first test cut.  With the blade set so it is the thickness of the stock above the top of the Base plus a little or in this case since the test piece is ½” thick the blade is set about 17/32” above the top of the base.  Once that’s done two test pieces are clamped in the jig with one offset the thickness of the one of the spare Finger Spacers used identified by the red arrow. 

With the bolt up against the right Side Brace the first pass using the dado set is made as in the top two photos.  Next, the Moving Backer assembly is moved so the bolt is tight to the left side of the gap and a second pass through the dado set is made shown in the bottom photos. 

To make the next cut the Moving Backer assembly is picked up and the bolt set one space over to the left per the top two photos.  The same process as above is used to make this set of cuts.  To make the remainder of the joints the process of moving the Moving Backer assembly over one space at a time then making the cuts is repeated until the whole edge is done.  The bottom photo shows the completed pair of test pieces.

After removing the pieces from the jig here is the test fit which to my extreme surprise fit perfectly.  Just snug enough to gently fit together without being loose.  No adjustment was needed but if it were here is how that works.  If the fit is too tight then the Index Guide in my case the bolt would have to be made thicker or the dado blade stack thinner which is why I added the .004” shim to the stack so there was an easy way to make the stack thinner.  On the other hand, if the fit is too loose then the bolt would need to be made thinner or the dado stack made thicker by adding another or different sized shim.

One other addition after I started cutting was to add a stop block (red arrow) clamped to the table saw’s rip fence.  It is set so I make the full depth cut but prevents me from sawing too far into the jig keeping the blade safely buried in the Spacer Base.

Next is to try and make a small-scale version of the wastebasket to test out how tapered sides work while using alternating ½” and 1” box joints instead of all ½” joints like the just completed test.

Next Up – Jig Testing & Making Prototype