OK, so we have already made the mallet in the previous step. Now on to the xylophone.
Cut the square-cross-section wood lengthwise to make two rectangular cross-sections. We cut each 3ft length lengthwise. One of these 3ft lengths is shown in the photo after we cut it. Just make sure you make the two sides as evenly thick as possible, so your pitches are on. You'll be tuning it later anyway but you should still try to do it to make life easy for yourself.
We used the bandsaw with a fence to keep it the same thickness all the way along. See photo. Then we sanded on the cut side. We were left with two rectangular bars per starting square piece.
Next you cut the bars to length.
HOW TO CHOOSE THE LENGTHS:
Get the lengths from the .xlsx file here: davidnhutch.com/files/keep/XylophoneLengths.xlsx
. I found some xylophone bar length calculators online (link is in the .xlsx file), and used that as a starting point for the Excel file. Basically, you input the total length of rectangular bar you have available and it will tell you how to cut 8 bars that use that length, making an octave of musical notes. These won't be perfect so we will tune them later, but you should try to cut them as accurately as possible anyway.
* Larger bars are better. Larger bars ring longer, make better sound, are easier to tune (because shaving a few mm off a larger bar does little while shaving the same amount off a smaller bar does a lot). However you don't want to go too large otherwise: (1) your wood may be warped and this will show for longer bars, (2) It may be too big for use by small kids, (3) Many of the wavelengths of sound may be below human hearing. I recommend keeping the bars less than 12" long, and for a small kids' xylophone a longest bar of around 7" is fine.
OK now you have your bars cut. Drill holes that are 1/4 and 3/4 of the way along the bar as shown. The holes should be much bigger than the shaft of your pegs (perhaps 1.5 times larger diameter), because the bars need to be able to freely move.
Next we will make the frame, then the suspension padding, then assemble it and we're done.