First post. I just completed my first cross cut sled and had a hard time attaching the rockler aluminum miter bars to the bottom. I finally came up with something that worked quite well for me. I used 1/2" ply as the base, ordered 1/4-20 x 3/4 flat head screws, 1/4-20 x 3/4" Flat Head Socket Cap Screws 18-8 Stainless Steel, Quantity 25, Countersunk Head, Allen Hex Drive by Fastenere: Amazon.com: Home Improvement, and this tap https://www.lowes.com/pd/DEWALT-1-4-in-20-2-Flute-M2-HSS-Drill-Tap/999959793. I shimmed the miter bars up in the slot, put double sided tape on top of the bars, laid the base down on top of the tape. I then ran the tap from the bottom of the bar through the 1/2" plywood base. The drill end of the tap went through the wood without difficulty. A 1/2" countersink in the ply from above and the screws went though from above the base into the bar. I left the tape in place trimming any away that was exposed. Works great.