nwcatman
Member
just read that if you run the lathe in reverse you can get a superior sanding finish. any tricks associated w/this? OTHER than ur motor has to have a back up switch on it!
REVERSE SANDING ??
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tbroye
Member
Wouldn't standing on the other side of the Lathe have the same effect?
I would wonder about the safety of doing it,
I would wonder about the safety of doing it,
leehljp
Member Liaison
And you could reverse the ends of the blank and it would be running backwards from the first way you sanded it. :biggrin:
Reverse sanding does work (so I have read) on larger projects such as larger bowls, plates and vases. Some more expensive lathes have this ability for such purpose.
Reverse sanding does work (so I have read) on larger projects such as larger bowls, plates and vases. Some more expensive lathes have this ability for such purpose.
MobilMan
Member
Tom. No matter which side of the lathe you are standing on- the lathe is still going the same direction. Try it. Altho it's not necessary on small items like pens, you can sand to 320-400, then lightly dampen the blank with water & let dry. That will raise the grain, then start at 400 & go from there.
marcruby
Member
It's not a bad idea to alternate sanding directions on bowls (pens are just to small to benefit). I don't know if it offers something better. You will still need to hand sand across the first sanding direction to preak up the sanding lines. For large jobs I cheat. I turn the bowl at about 200 rpm and use a sanding disk in a hand drill. The effect is like a random orbit sander. I usually do that up to 400 grit and then use 600 and steel wool the hard way.
Marc
Marc
DavidSpavin
Member
The way to tell if you would benifit from reverse sanding is to run your fingers round the blank (with the lathe off) if you feel a differance depending on which direction you are going then reverse sanding will help. I find the more open the grain of the wood the more likley reverse sanding will help. My lathe will run in reverse and I often do reverse sand, just rember to put the sand paper on top not under the blank.
jeffj13
Member
While the lathe is moving in the same direction, standing on the other side changes your orientation. It has the same effect as reversing the direction the lathe spins.
jeff
bybill
Member
Not quite! A spot on the blank is still moving in the same direction in relation to a stationary object (the sandpaper.)
MDWine
Member
I don't sand much with the lathe turning, only to remove tool marks.
Once the surface is level, I turn the lathe off and sand with the grain.
MM all the way down... just my .0155555
Once the surface is level, I turn the lathe off and sand with the grain.
MM all the way down... just my .0155555
I don't think that reversing the direction of sanding does anything to a pen.
Stopping the lathe and sanding along the length of the pen is more important than reversing the direction because it breaks up the circular scratch pattern. Reversing the lathe does nothing to remove the curcular scratches. It only makes them run around the piece in a different direction. The hand sanding will also remove any wood fibers that have been laid over by the spinning lathe.
Stopping the lathe and sanding along the length of the pen is more important than reversing the direction because it breaks up the circular scratch pattern. Reversing the lathe does nothing to remove the curcular scratches. It only makes them run around the piece in a different direction. The hand sanding will also remove any wood fibers that have been laid over by the spinning lathe.
cozee
Member
Reverse sanding works quite effectively on, as Russ mentioned, the wood fibers which do lay over. I haven't seen much when doing pens but for larger items it definitely makes a difference. A simple flip of the switch and the lathe is running in reverse.
Conversion for most lathes only requires a DPDT On-On or On-Off switch and a 4 pieces of 14ga wire. All one needs to do is determine a mounting spot for the switch, hopefully in an area within the speed control box/area. Unplug the wires coming from the speed controller (SCR) going to the motor. Connect these to the two center posts on the switch. Now fabricate 4 wires, 2 to connect to the out puts of the SCR to either pair of posts left on the switch. Now, connect the other 2 wires with the ones you just connected from the SCR. Take the ends of these two wires and connect them to the last 2 posts but criss-cross them. By criss-crossing them, you are changing the flow of the DC current changing positive to negative and negative to positive as they flow to the motor. You will not hurt the motor as DC armatures will typically run either direction. When running your lathe in reverse for the first time, run it at it's slowest speed for a few minutes so the the commutator brushes will wear properly as they have gotten used to running in one direction. And when a face plate, scroll chuck, or any other threaded on device is used, run in reverse only as needed and at slowest rpm to get the job done. Mark the switch well as to the forward and reverse positions. Get in the habit of always switch back to forward when done with reverse. And always double check before switching the lathe on!
Circular sanding scratches can many times result from applying to much pressure on the sand paper. I see it too many times in the auto body trade. Sand paper is designed to float on the surface, not dig in and do what tools are supposed to do. Using to heavy of a grit also contributes to the problem as does not sanding well enough and making to big a jump in grits. And keep that paper moving! The faster the lathe is running the faster it needs to move around!
Conversion for most lathes only requires a DPDT On-On or On-Off switch and a 4 pieces of 14ga wire. All one needs to do is determine a mounting spot for the switch, hopefully in an area within the speed control box/area. Unplug the wires coming from the speed controller (SCR) going to the motor. Connect these to the two center posts on the switch. Now fabricate 4 wires, 2 to connect to the out puts of the SCR to either pair of posts left on the switch. Now, connect the other 2 wires with the ones you just connected from the SCR. Take the ends of these two wires and connect them to the last 2 posts but criss-cross them. By criss-crossing them, you are changing the flow of the DC current changing positive to negative and negative to positive as they flow to the motor. You will not hurt the motor as DC armatures will typically run either direction. When running your lathe in reverse for the first time, run it at it's slowest speed for a few minutes so the the commutator brushes will wear properly as they have gotten used to running in one direction. And when a face plate, scroll chuck, or any other threaded on device is used, run in reverse only as needed and at slowest rpm to get the job done. Mark the switch well as to the forward and reverse positions. Get in the habit of always switch back to forward when done with reverse. And always double check before switching the lathe on!
Circular sanding scratches can many times result from applying to much pressure on the sand paper. I see it too many times in the auto body trade. Sand paper is designed to float on the surface, not dig in and do what tools are supposed to do. Using to heavy of a grit also contributes to the problem as does not sanding well enough and making to big a jump in grits. And keep that paper moving! The faster the lathe is running the faster it needs to move around!
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smitty
Member
I installed the reversing switch in my jet mini lathe. It cut my sanding time in half. I reverse the direction after each 3 grits of MM. I no longer have to sand with the grain and get a much better finish. Just my 2 cents worth.
PaulDoug
Member
I don't sand much with the lathe turning, only to remove tool marks.
Once the surface is level, I turn the lathe off and sand with the grain.
MM all the way down... just my .0155555
Michael, I have not read of this way of sanding before. Are you talking the way you sand pen blanks? I'm just curious about why you chose this method and what the advantage is to you.
Thanks.
jeffj13
Member
Really? Seems to me that if I am standing on the traditional side of the lathe, a spot on the blank is moving from north to south and if I am on the opposite side of the lathe, it is moving from south to north.
That said, I agree with Russ, sanding east/west is far more important that reversing the lathe.
jeff
cozee
Member
:biggrin: Stand at the tail stock end of the lathe and traditional rotation is counter clock wise. Doesn't matter which side of the lathe you stand on, it is still going CCW. In reverse, it rotates clock wise.
Russ is correct in that is important for correcting the error in sanding which leaves those pesky little swirls and circles. Too many turners simply slap the sand paper on the blank and figure if they press a bit harder the paper will work better and faster. And then because of it, more steps are needed to rectify the problem. And the closer a blank nears finishing, the lighter the touch one should take. Especially since finer grits cut faster.
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TellicoTurning
Member
No, standing on the other side of the lathe, the blank is still turning in the same direction, you are just approaching the blank from a different angle..... besides my lathe sits against a wall and I would have to have some method of hanging off the wall...
