Sanding Bow - rounded surface tool

found this kind of tool useful sanding rounded and several other shaped surfaces but wasn’t happy with the performance of similar things.

what to know about this

first I just designed versions around some short threaded inserts I had on hand but updated with versions that use regular hex nuts or square nuts so far. there are six sizes to choose from: S, SW, M, MW, L & XL (pictures show sizes S, M & L) this construction makes it a lot easier to tighten the sandpaper to your needs, the oversized nut serves as a fingerrest to ensure good grip. mainly made for fine sandingpapers but successfully testet up to 60 grit. * appears there is a usage I did not have in mind, a friend printed one (golden one on the pictures) and she is using it for manicure purposes. seems to be quite versatile *

hardware & tools

the lenght of the screw to be used depends on chosen size, used hardware (nuts/inserts) and if you like to use a thumbscrew on top or the sunk version, therefore I cant give you exact dimensions.

bow size screws threaded inserts hex nuts square nuts sanding-paper

S M3 x 12-15mm M3 x 4mm* M3 M3 (1.8 x 5.5mm) 10 x 148mm

SW M3 x 12-15mm M3 x 4mm* M3 M3 (1.8 x 5.5mm) 15 x 148mm

M M3 x 15-18mm M3 x 4mm* M3 M3 (1.8 x 5.5mm) 10 x 186mm

MW M3 x 15-18mm M3 x 4mm* M3 M3 (1.8 x 5.5mm) 15 x 186mm

L M4 x 22-28mm M4 x 4mm* M4 M4 (2.2 x 6.9mm) 15 x 278mm

XL M4 x 30-36mm M4 x 4mm* M4 M4 (2.2 x 6.9mm) 20 x 370mm

* M3 x 5.8mm, M4 x 8.1mm will also fit if you remove the excess material by inserting a screw from the bottom while it’s still warm

you will need a soldering iron for the threaded inserts, a sharp knife to cut the sandpaper stripes, a drop of superglue for the hex and square nuts, an allen key if you don’t use a thumbscrew. for easy cutting of the needed sandpaper stripes I included templates , to fit L and XL on smaller printbeds they have a puzzle-cut that can be glued after printing. (there are a couple mm included to adjust tension to your needs)

my favorite tightening solution is the knurled thumbscrew by Elothan you can see on the pictures.

stop palaver, start printing and making things

these settings are just guidelines, you want to print it fairly strong

material nozzle layers perimeters infill top/bottom layers support brim

PETG 0.4 0.2 2+ 30%+ 4+ none* no**

* only for a cleaner central hole in the bow ** if your bed sticks good

assembly is pretty easy, depending on the chosen version you have to melt the inserts in from bottom side (opposite of nut) or fix the hex/square nuts with a drop of superglue. it still takes a little practice to hold tension on the sandingpaper with two fingers of one hand and tightening the nut with the other one. (gently folding the cut sandingpaper in the middle or marking it with a pen helps with correct alignement)

update history

—> added hex nut versions —> added square nut versions —> added wide versions of sizes S & M called SW & MW —> added nuts with sunk screw heads for the use without thumbscrew —> updated description for better overview

what else

if you need versions using other hardware or slimmer/wider sandingpaper stripes let me know!

happy printing! if you like my work I highly appreciate every make and rating, same for likes, remixes & shares. donations will be forwarded to sea-watch.org