Indexing Jig for T-track Beds.

[4DThinker]

I've mentioned this before, but this time I've got photos. The end brackets were some scraps of 3" x 3", 1/4" thick aluminum L I had from a past project. The index wheel was cut from 3/8" thick high density plastic. The wheel has circular arrays of 8 and 6 holes, and the bracket has two pin holes one for each array. In the jig is the only thing I've cut so far, a 4-sided table leg with some VCarving, fluting (for the taper), and simple profiling on the line for the cove cuts. Anything would be possible though, including 3D carving if you have Aspire. Remove the 5mm pin, rotate 90 degrees, Insert pin, then run the file again. Repeat 4 times, or 3 or 6 or 8 with the wheel as it is.

[milo30]

That's a great technique and super simple. Thanks for sharing.

[BillK]

4D,

Nice job on this. I've had a similar idea but no time to execute it. A couple of questions for you.

How do you align the two separate halves?

Is the work piece screwed to the index plate?

Thanks!

[4DThinker]

4D,

How do you align the two separate halves?
Is the work piece screwed to the index plate?

Thanks!

The holes for the bolts into the t-track are both centered in each end, and so I usually measure from the end of my bed to the bolt holes on each end. That usually gets me right on target, but once my blank is in place I jog the router end to end to make sure it runs parallel to the blank. If I'd had two pieces of the aluminum bracket that were the same I'd have made them the same width so you could measure to the the edge of each end piece. You can also slide both pieces down the same slots and run 90 degrees to what I've show and then they are lined up with track automatically. Those bolt holes also let the ends go in at 45 degrees, so you can run your piece diagonally for slightly longer pieces if you want.

Yes, the index plate has countersunk holes for wood screws to screw into the index end of the blank. 4 holes, but two is enough to use. A center bolt the opposite direction holds it tight to the bracket after indexing pin is in.

4D

[4DThinker]

For those interested in making their own, here is the indexing plate pattern. The countersink holes in the center are actually to be cut on the other side. I used two of the pin holes as alignment holes, cut into the spoil board 1/4" or so so that when flipped over and pins inserted the piece is lined up perfectly. The center pocket is for the head of a standard t-track 5/16" bolt. VCarve 7. Extra lines in the drawing were me laying out the holes I drilled into the bracket base.

Enjoy!

[rungemach]

Hi 4D

nice work on the indexing plate.

you could turn the whole thing 90 degrees ( with the material sitting front to back) and have the tailstock slide in the table slots for length adjustment.
That also would allow you to modify the rear mount to include a stepper drive (headstock) on the rear of the machine. That is how I ended up doing mine.

If you made an extension for the table extrusion, the tailstock could come out farther to the front and you could in theory double your carving length if you could accurately flip the workpiece end to end and carve each separately.

Lots of possibilities.

[4DThinker]

Yep, the possibilities are endless. You get some length adjustment just by choosing different t-slots when cutting as shown. Not as fine of adjustment with the limits, but the dead center is as long as it is to make up though. The bolt holes into the t-track are diagonal from each other. Slide the brackets in at 45 degrees across corners if you want to try a longer piece.

BTW, when my Shark hiccuped during the shown cut it went past the index end and cut right into the index wheel. The one in the photos was the second one I made, although I was able to finish that job with the damaged one thanks to the mistake not cutting into the holes I was using.

Knowing about the CTRL-E settings now I may look for a stepper to play with. No matter what the belt/pulley ratios were a setting could be changed for the axis in use to cut without stretching or shrinking the drawing.

[gordread]

This is great. I have my aluminum brackets. Now to make the mount/indexer.

Thanks 4D for another great idea.

Gordon

[4DThinker]

Glad I could help, Gordon.

I'd love it of you would post photos of yours when it is finished. Especially if you include any improvements.

4D

[gordread]

I most certainly will. I was thinking about integrating a lathe chuck, but I will start out with what you have just to get going.

Gordon