1/3 sheet sanders

question - what is with these new 1/3 sheet sanders popping up.

Random orbit rectangle sanders - is what I see when I see them. Do any of you all use one - if so how often and does it really help vs a 1/4 sheet and a 5 or 6 inch RO.

I am no expert on them, but I do know they are nothing new. I borrowed one from my neighbor to work on a large R/C boat I built as a teenager more than 30 years ago. It was a corded model. I have to say though that random orbits and the 1/4 sheet have been a lot more common since.
The RO sands much faster in my experience, and it is my preferred sander of the two. However, the fractional sheet sanders have square corners so they can get into places where the round RO disc can’t get. I would assume the 1/3 sheet would be better for working on flat surfaces than the 1/4 since its sanding surface is longer, but how much that matters in real life I don’t know. Right now I have a 1/4 sheet and an RO, and I only use the 1/4 when I have to do inside corners.

There seems to be new interest in this type of sander since ToolGuyd Stuart posted about the new Makita cordless:

New Makita Tool Announcements – Spring 2022 (toolguyd.com)

It features orbital motion - but I’m not sure that these sanders randomize the orbits - so you may expect some scratch patterns that are different and/or more noticeable (grit fot grit) compared to a true RO sander.

I’ve used RO sanders since Porter Cable introduced the first one ever made (#7336) - based on an angle grinder. Before that - I often used a Rockwell-Porter Cable #505 1/2 sheet sander that used in-line motion, I still pull this tool out from time to time and it works well despite it being 40+ years old. Here is a Makita 1/2 sheet sander:

I also have three 1/4 sheet sanders including a Porter Cable 330, Hitachi SV125G and Ryobi P440 cordless - scattered around my 3 domiciles. I more often grab one of my RO circular pad sanders - favoring a Mirka Ceros in my shop for furniture finishing.

Here is an old Amazon link to the PC 505 - which is no longer made - but do turn up for sale used on eBay etc.

Some of the attraction with this was its larger (1/2 sheet) size - so it covered more surface. It is sort of like Papa Bear (1/2 sheet), Mama Bear (1/3 sheet) and Baby Bear (1/4 sheet)

I should have also mentioned I got one marketing e-mail from Triton tools with their new 1/3 sheet sander.

I think I see Bosch puts one out now - and of course as mentioned that makita one which is cordless of their corded one.

I’ve not seen one used before and thought it odd. sort of a neat idea and I guess it would cut down time. In theory more surface area than a 5in RO. OK and no special paper purchase. I guess I might consider one.

For bigger surfaces I was thinking of going belt sander.

A belt sander is much more of a roughing tool while the fractional sheet sanders are more for finish work. Even with a fairly fine belt the belt sander will take off material much faster than an oscillating type will. It also takes more practice to keep a flat surface with a belt sander, it’s easy to inadvertently gouge or burn the work. The sheet sanders are nowhere near as aggressive and its very hard to gouge or burn.

Also, Fred raised a good point about the scratch patterns left by the fractional sheet sanders. They can indeed leave much more obvious circular marks than an RO does.

my process so far as been to do all sanding with a 5in RO. from 60/80 to 220/300 or even 400 once.

and I have a 1/4 sheet that is rarely used other than for square bits. and my OMT is a trilobe detail sander. but for big areas like my eating room table (not dining room, this is off the kitchen 5 ft table) I ended up taking my 6 inch RO porter cable polisher (I bought it years ago for polishing cars) and put PSA backed papers on it. worked fine - but I see the appeal of something bigger. I assume these 1/3 sheet jobs also have a hole puncher for though plate dust extraction. which is why I love my 5in RO.

I am curious how the dust extraction works on the new 1/3 sheet models.
The one I used many years ago did not have any kind of dust extraction or collection. No holes in the platen, no fan, no vacuum port, no nothing. You had to be pretty careful because the sandpaper would easily load up. There was also the risk of some errant large bit of grain or some other hard particle getting between the paper and your work and leaving a bunch of scratch marks, so I found myself brushing off the paper and the workpiece very frequently. My 1/4 sheet is the Dewalt 20V cordless, it came with the hole puncher and I have to say I’m impressed with how well its dust collection works even with just the bag on it.

Belt sanders are indeed usually more aggressive. I have a few older corded ones - including a chain-drive wormgear Rockwell Porter Cable 503 that I still take out when I really want to remove lots of material. Its 15 pound weight sort of rules using it for any length of time except resting on a surface. I bought a PC 360 for lighter-duty work - but it is also not exactly a light tool. I believe that both tools are discontinued - but I see the 503 selling for steep prices on eBay.

If I were to buy another belt sander today for major stock removal - it would probably be a Makita:

Amazon.com: Makita 9403 4" x 24" Belt Sander, Teal : Everything Else

I haven’t used a 1/3, but I have a 1/2 sheet and find it a good medium between the belt sander and the ROS. It’s more efficient than a ROS by a good bit at lower grits and the swirls don’t matter at that stage. It’s safer by far than the belt sander when you don’t need to hog out a bunch of material and it holds flat better than either. Plus, sheets are way cheaper. If you do enough woodworking with large, flat surfaces it’s worth the add. Otherwise an ROS is probably fine and the money would probably be better spent upgrading to a 6" ROS (which is very much worth it).

I wonder if collectors are driving up the price of those old 503s?
I’ve been after a 2-inch wide Wilton “bullet” style machinist’s vise for a long time now. They no longer produce this size. Used ones sell for several hundred dollars on Ebay, sometimes well over a thousand if the original paint is in good condition and the factory logo stickers are still present. I couldn’t care less about the condition of the paint, I want to use it for work not display it on a shelf somewhere, but the collectors certainly seem to be the ones driving that market.