Sanding techique

[Dan_F]

I find that as soon as I start sanding, my blanks start getting "bumpy" (logitudinal humps), I assume due to uneven abrasion of the layers of wood. This became especially apparent with some spalted maple I'm currently working with. Is there anything that can be done to minimize this? I've been using the sanding strip wrapped around the blank technique, but notice it when using the pads of my fingers as well. Thanks,

Dan

 

[fiferb]

Try using a sanding block. This will prevent the softer areas from being worn away.

 

[wdcav1952]

Dan, you might also try a lighter touch with your sandpaper.

 

[DCBluesman]

For the most part, these should disappear when you sand longitudinally. In fact, you may need to do all of your sanding that way.

 

[SuperDave]

Dan,

Also try sanding at a little slower RPM and keep your sandpaper moving at a good rate of speed.

 

[MichaelS]

There are several things that you might want to check.
The mandrel shaft is not bowed due to the live tail stock center being to tight.
Curling nut is not to tight.
Dull tools causing you to apply to much pressure to the turning.
Turn off the lathe and check for round. If you are out of round at this stage sanding will make it worse. Sand at a low RPM, then turn off and sand longitudinally. Do this for each grit.

 

[Dan_F]

Thanks for the replies.

The "bumps" were occurring during sanding, blank was smooth and round before that. I wasn't using a mandrel or bushings for the sanding part, just the tube between centers.

I'll do some more experimenting with speed and pressure, and make a little block to try. I do sand longitudinally before going on to the next grit, but once they form it's hard to get rid of them. It's nothing I can see, just feel in my fingertips (through the sandpaper) when the blank is spinning. I would think it could cause a problem with sanding through the finish.

Dan