There were a few questions about the sander so I thought I’d answer them here.
Condor1 & Blake:
Yes, I simply push the stock under the drum freehand on a sled. The sled is nothing more than a piece of plywood with a sacrificial little wedge-shaped fence that is tapped into a saw kerf at the operator end. That keeps the drum from trying to spit the wood back at you. (By the way, I have found that the same safety rule for table saws applies to this bugger…stay to one side – out of the line of fire – in case of kickback.) The drum turns so that it is working against you as you push. Since you won’t take very much off on a pass, this proves to be very workable. The drum is 3” in diameter. My motor runs @ 3450 rpm and I used a 2:1 pulley ratio to step the drum rpm down to somewhere in the vicinity of 1725. So far I have only used 120 grit paper on the drum and that has proven to be a very workable grit. It leaves an amazingly smooth finish, even on extremely thin (.031 or 1/32”) strips that I have milled out (of ebony, even!) for my ship modeling.
This is a view of the “back” of the sander and the coarse adjustment part. There is a 1/2” X 1/16” aluminum strip that runs vertically between the stationary base and the moving (table) support to keep the table support aligned. It is fixed (epoxied) in a slot in the fixed base and it runs free in a groove cut in the moving table support. It is just visible at bottom-right next to the cove-shaped cutout. The knobs have threaded studs that engage blind nuts on the inside of the base. Almost all of this hardware came from Reid Supply, which has a fabulous selection of goodies.
Here is the fine adjustment. The rod is 3/8 X 16 threaded rod from the local Ace Hardware. The adjustment knob is a “Quick-Acting” knob from Reid (p/n QK-3). It has a threaded, oblong hole through the center that allows you to tip the knob one way and it releases from the thread. Tip it back the other way and it engages. I made the little table that supports the knob by designing it in my head as I cut. Nothing fancy here. It’s maple.
This is the pivot arrangement between the fine-adjustment rod and the underside of the table. A couple of gate barrel bolt assemblies (Ace Hardware – brass) were dismantled to accomplish this. The only reason I needed two assemblies was because I needed two of the sockets. I drove the knob out of one of the barrel bolts and cut it to length. Then I ground the 3/-16 rod down to a place where it would press-fit into the hole in the barrel bolt and finally I soldered the joint.
And yes, Blake, I think we definitely looked at the same website. I wonder what happened to it?? There’s another one here that has similar thoughts.
The pressure to feed the wood through is entirely dependent on how much you try to sand off in a pass. Taking off .002 takes very little pressure; taking off 1/32 requires considerably more.
Oh, by the way…Sandy…about 25 miles west of Mt. Hood. Where are you?
After I turned the drum on the lathe, I assembled the sander. Then I stuck a sheet of 80 grit sandpaper to a piece of 3/4 MDF and ran it back and forth on the table under the drum. This does a final “squaring” of the drum with the table. I suppose it might be possible to completely turn the drum this way once you got it cut to an octagonal shape, but it would probably prove to be a long and tedious process.
The motor is simply mounted on a 3/4” BB plate that is hinged at one end and there is an arrangement at the other end similar to the underside of the table fine adjustment – for adjusting the tension on the belt. Only I just used a couple of washers, a wingnut and nuts on either side since belt adjustment wouldn’t happen very often. (See below)
Any other questions? I’ll try to answer. I built this a couple of years ago and the ol’ memory ain’t what it used to be (if it ever was!)
And yes, to address the obvious: I suppose you could build a guard to put over the belt/pulleys if you so desire. I am the only one who ever gets near this thing (no kids in the house) and I stand on the side opposite the belt when I’m using it, so I am not terribly concerned.
-- 73, Bob