Hello folks. Many of us have built the SGA Thanks to OneArmed for posting the first thread and finding source for the guide rails. The SGA is so handy, it's one of my much used tools in the shop.
A few days ago I was sanding a Damascus Billet and got it down around 1/4" thick and starting to look pretty good. I decided to check to make sure the magnetic chuck was still even, so removed billet, adjusted chuck so it was just "kissing" the chuck face. Looked good. I went to do something else and an hour later when I came back I stuck the billet back on and moved to sand - WHAM!!!!! I'd forgot to move chuck back to provide clearance for the 1/4" billet. With the SGA running at WAO at 4,050 SFPM it really shot that chuck thru, billet went flying and something is broke in the adjustment portion.
OK, no big deal, I built the darn thing I can fix it. I take adjustment portion apart, find the problem and fix it. Great, now ready to go again. Wrong - there is big time slop in the chuck now. Take a look at photo below:
You see the round rods on inside of the rails? That is where the rollers run with no slack (heck, we know how it works). After the WHAM! something happened to cause too much slack and gave wobble in the chuck. I couldn't see anything wrong - it all looked good. I took a roller off the slide and found what happened. See the brass circle on the slide (left side)? The screw that holds the roller screws into that, and if you look close you can see the screw hole is offset from center a small amount. This gives the ability to rotate the brass circle and remove all slack. See the two small holes on the edges of brass circle? That's got a sharp pointed setscrew so the brass can't move in use. I "think" it's going to work now. It feels good, no slop - and is a tad tighter than when new but I think I'll leave it there for now.
Shows what can happen with a moment of "not thinking" - which seems to happen more often the older I get.
A few days ago I was sanding a Damascus Billet and got it down around 1/4" thick and starting to look pretty good. I decided to check to make sure the magnetic chuck was still even, so removed billet, adjusted chuck so it was just "kissing" the chuck face. Looked good. I went to do something else and an hour later when I came back I stuck the billet back on and moved to sand - WHAM!!!!! I'd forgot to move chuck back to provide clearance for the 1/4" billet. With the SGA running at WAO at 4,050 SFPM it really shot that chuck thru, billet went flying and something is broke in the adjustment portion.
OK, no big deal, I built the darn thing I can fix it. I take adjustment portion apart, find the problem and fix it. Great, now ready to go again. Wrong - there is big time slop in the chuck now. Take a look at photo below:
You see the round rods on inside of the rails? That is where the rollers run with no slack (heck, we know how it works). After the WHAM! something happened to cause too much slack and gave wobble in the chuck. I couldn't see anything wrong - it all looked good. I took a roller off the slide and found what happened. See the brass circle on the slide (left side)? The screw that holds the roller screws into that, and if you look close you can see the screw hole is offset from center a small amount. This gives the ability to rotate the brass circle and remove all slack. See the two small holes on the edges of brass circle? That's got a sharp pointed setscrew so the brass can't move in use. I "think" it's going to work now. It feels good, no slop - and is a tad tighter than when new but I think I'll leave it there for now.
Shows what can happen with a moment of "not thinking" - which seems to happen more often the older I get.
