Over the years of this blog, we have shared a number of shop-built sanding devices including sanders for the lathe, and various rotary sanders for drills such as our flap sander that uses sandpaper rolls. This month, we are dealing with how to get your sanding supplies inside various-sized holes.
Recently I was making pierced gallery rails on my CNC. The rails came out quite well, but I needed an efficient method for sanding inside all of the circles in the rails. My first thought was one of the drum sanders from my set, but they were too big. The obvious solution was to wrap sandpaper around an appropriately sized dowel. I could have used PSA backed sandpaper or double-face taped the sandpaper to the dowel, but these options are prone to heat failure and make changing grits too time consuming.
The solution was to wrap a piece of sandpaper roll around the dowel after slipping it through a slot cut in the end of the dowel. This allows you to select a dowel slightly smaller than the hole to be sanded and cut a slot across one end as long as the roll sandpaper is wide.
I have found that how you wrap the sandpaper roll section matters. Slip the sandpaper into the slot with 1/4-1/2" exposed through one side, and the remainder out the other, about 1-1/2 turns around the dowel. The long end wraps over the short end, helping to keep the sandpaper roll held in the slot.
Now your drill can rapidly and cleanly sand the inside of various-sized holes. I have found that with the proper length of sandpaper roll (this is where the 1-1/2 wraps around the dowel comes from) you can even move from hole to hole without stopping the drill or needing to hold the wrap to insert it.
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