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Hi -

What is the difference (besides the obvious) between a Random Orbit sander and a 1/4 pad sander ?

I have a 1/4 pad sander - should I buy a random orbit ? I wanted to sand my sides and backs a little to thin them down the final bit after planing and removing plane marks. Any reason why the RO is better ?

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I use RO sanders for most jobs. By the time I'd use a ¼ sheet vibrating sander, I'm usually to the hand-sanding stage.
Years ago I had a Rockwell Speedbloc- it was a good sander but the pad mounts hardened up and it started to vibrate my hand more than the paper.
I don't think any sander with a soft pad will do the job you want in thinning sides- I'd hand sand with a hard block, I think.
If you do use the power sander, be careful not to thin the edges too much.

Cheers
John

Well it depends on the task and the pads. when sanding finish ROs will some times leave micro swirls as soon as the paper starts to load up any. finish sanders are not as bad about this. Ro it does not mater if you are sanding with or across the grain finish sanders are intended t be used only with the grain.

So what I have now is a finish sander ?

Then I would need a RO sander for the heavier removal ? heavier sanding ? and possible side thinning ?

I like planing by hand .... but... an RO sander is tempting with their relatively low price.

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It's this new idea from recent decades that everyone gets a participation award. - MUX

Typically that is what a 1/4 or 1/2 sheet sander is called. The action is back and forth

Random Orbit sander is Better on coarser grits because you can remove the previous Marks from the coarser paper better , IE: 80 Grit to 120 Grit to 180 / 220Grit ALso , MOST abrasive manufacturers will Recommend that your never jump More than 2 grits in coarser paper IE 80 to 120 ok 80 to 180 will not take all the marks out .

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For side thinning using power tools, you could consider:
- a small drum sander in your drill press and a fence (if you have a ShopSmith or a lathe some other possibilities will be obvious).
- a Safe-T Planer (very handy tool) in your drill press
- a flat disc (Gilbert-style) sander in your drill press

Any of these is more set-up work than just grabbing the RO sander, but will give more uniform thickness.

In 'easier' woods you should be able to thickness with a very sharp hand plane, light cuts and a flat bench or workboard. What sort of wood are you thicknessing?

Cheers
John

I use a RO. I use a drum sander for the main thicknessing, and then a RO and hand sanding to feather the thickness down towards the edges and clean up any marks. However, with that being said, I must admit that I am working on my first guitar, so I don't know that my advice is the best. But my top did turn out very nice with no problems, so take it for what its worth.

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Actually I did use a Safe-T-Planer - which worked nice - but the thickness is not very even .... So it is all about .125 inch to .14 inch - I wanted to use the RO to bring it all to .12 or .11 - I also have some thin spots as well which are about .10 - those areas I am avoiding.
I am using a #5 plane with a hock blade which works well... I just started thinking that once I plane everything, I can follow with the RO for the areas I could not thin down perfectly.

_________________
It's this new idea from recent decades that everyone gets a participation award. - MUX

A random orbital is considerably more agressive than a vibrator. That's the main difference.

Why not follow up your planing with a scraper? If you've got them close and just need to clean things up/remove plane tracks/take a hair more off, then a well honed and burnished scraper will do a great job, be very controllable, easy to set up, and will be cheap. Besides, shavings are always nicer than dust.