Cryptic crossword No 915

Very clever! Thanks, Salix. I especially liked 1A, 4A, 17A (for the answer), 6D, 16D and 20D. Suggestions: delete the full stop in 1D and rewrite 22A (it's inaccurate). And the numbering at 25A seems to be wrong, but I don't know if you can do anything about it. Lovely puzzle though, and a fun exploration of the theme.

Thanks for sharing this one, Salix - some fun clues. Favourites for me were 16d, 24d. A couple of spoilerish technical points in reply…

Thanks for the puzzle Salix, good fun stuff! I particularly liked 1a (smooth surface and neat construction), 9a (smooth and neat), 11a (neat), 17a (clean), 1d (nice assembly), 2d (smooth), 6d (clean), 16d (likewise) and 24d (neat)...