Best tool for sanding 90 degree inside corners

[scott vroom]

I'm looking for recommendations on how to sand 90 degree inside corners where the grain on both boards runs perpendicular to the change in plane. This is for a commercial shop and am willing to invest in quality tooling.

[Lee Schierer]

I have used my Bosch multitool to do sanding in hard to reach places. It takes a little finesse but it does a good job. The triangular pad with the velcro allows for quick grit changes.

[scott vroom]

I have used my Bosch multitool to do sanding in hard to reach places. It takes a little finesse but it does a good job. The triangular pad with the velcro allows for quick grit changes.


Lee, what's the oscillation pattern on the Bosch multitool? Is it a circular pattern? I've got a Festool RTS 400 EQ (rectangular) sander that has an orbital pattern. Being rectangular, it fits quite nicely into inside 90's...the problem is that the orbital motion makes a groove on the board perpendicular to the one I'm sanding. In other words, if I slide the sander all the way into the corner, the adjacent corner is cut by the orbital action. I believe that any orbital action sander is going to have this problem, including the orbital oscillating multi-tools. How do you overcome this?

A linear sander such as the Festool LS130 would avoid the problem, but then you're sanding straight across the grain.

I'm not sure there is such a tool as I'm looking for. I'm sure many would respond by saying to do the finish sanding prior to assembly, but there are times when post-assembly sanding is unavoidable, such as interlocking dado shelving where woodfiller is often needed to fill small gaps right at the 90 degree intersections. For those situations, I'm considering picking up a linear sander and doing the cross grain sanding with 320 or higher grit to knock down the wood filler, then use a block to hand sand parallel to the grain to eliminate cross-grain marks. Very tedious and time consuming.

[Dominic Carpenter]

I use a piece of sand paper folded over a card scraper, old chisel or similar thin metal object I have laying around he shop.

[scott vroom]

I use a piece of sand paper folded over a card scraper, old chisel or similar thin metal object I have laying around he shop.

Dominic, that's probably going to be the best answer....I was hoping for some kinda miracle tool but in the end tried and true methods are tried and true for a reason :)

Thanks guys for your interest.

[glenn bradley]

I do as Dom does if I find myself in that situation; it happens now and again :o. The "kinda miracle tool" you are looking for is to sand prior to assembly . For inside areas I often pre-finish after sanding.

[Chad Helme]

Similar to the "scraper/chisel" method, I often fold sand paper over the thin end of a cedar shim/shingle. The flex in the shim allows you to apply just the right amount of pressure and the soft wood can be trimmed down easily to get in the tightest of places.

[Stephen Musial]

I use a plane iron and either use it as a scraper away from the joint or use it as a chisel toward the joint. Fast and no sanding marks.

[jack forsberg]

I'm looking for recommendations on how to sand 90 degree inside corners where the grain on both boards runs perpendicular to the change in plane. This is for a commercial shop and am willing to invest in quality tooling.


what you want is a bottom Scroll sander the best US made one were Ekstrom Carlson 23 and the 123.
http://vintagemachinery.org/photoindex/detail.aspx?id=4381

these use long cloth belt 12 feet or longer to run belts over a platen you drop your pattern over just like you would a spindle sander.

Oliver made one too there 190 i have that model(1942) and seen one go on eBay go for 250. These are going to be 3 phase machine but motor swaps are generally easy.

the UK phillipson sanders are about 10 grand so there not cheep and the reason i looked for used



http://www.daltonsmachines.com/osb/itemdetails.cfm/ID/-Phillipson-CBS1-Contour-Belt-Sander_96

here is mine after a rebuild.


http://www.youtube.com/watch?v=bNZrBlN8MHQ&feature=c4-overview&list=UUI6jpIs2zjN9DmVvK2ZAWXA

[Bob Michaels]

Just thinkin' ... how about cutting a piece of sheet metal to lay on the opposing grain. That would prevent your sander from cutting into the other piece. Swap the metal to the other side of the 90 to complete the task. I may be blowin' smoke here...just thinkin'. I had this issue just the other day but didn't try the sheet metal idea yet.

[Don Huffer]

I sand before assembly. At the very least sand the areas a sander can't get to.

Don

[Lee Schierer]

Lee, what's the oscillation pattern on the Bosch multitool? Is it a circular pattern? I've got a Festool RTS 400 EQ (rectangular) sander that has an orbital pattern. Being rectangular, it fits quite nicely into inside 90's...the problem is that the orbital motion makes a groove on the board perpendicular to the one I'm sanding. In other words, if I slide the sander all the way into the corner, the adjacent corner is cut by the orbital action. I believe that any orbital action sander is going to have this problem, including the orbital oscillating multi-tools. How do you overcome this?


The action on the Bosch is slight rotation back and forth about the pivot screw where the blades or sand pad attach. I've found sanding grits down to 220 for the trianglular pad, but you can cut your own from 6" velcro disks. You could probably trim the triangular pad to any shape you want with a hack saw.

[Jim German]

Why not just put a thin piece of sheet metal on the opposing board to prevent the oscilation from sanding that panel?

[Scott Austin]

I also use a Bosch multi tool, but I use a 5" h&l sandpaper on it so it is sanding both sides of a 90 at the same time. Could do this and finish up hand sanding.

[Andy Pratt]

fein multi tool with triangular sanding head (the one with the dust collection) and go up to one grit higher than whatever you are using since the scratches are more noticeable than with a ROS

[Jason White]

Get this one. It's one of my most-used sanders...

http://www.festoolusa.com/power-tools/sanders/dts-400-eq-orbital-finish-sander-567871


I'm looking for recommendations on how to sand 90 degree inside corners where the grain on both boards runs perpendicular to the change in plane. This is for a commercial shop and am willing to invest in quality tooling.

[Russ Kupiec]

Another vote for card scraper.
Why sand? Negotiating a vibratory device inside a corner takes more finesse than a few strokes with a slow motion scraper. No cross grain witness marks from the scraper.

[Jerry Olexa]

A multi tool will handle it quickly but the others have good hand tips....BEST to sand prior to assembly..

[scott vroom]

Get this one. It's one of my most-used sanders...

http://www.festoolusa.com/power-tools/sanders/dts-400-eq-orbital-finish-sander-567871

I already own a 400 EQ, Jason. The problem is that is it an orbital sander and cuts grooves into the adjacent surface when sanding tight into the corner.

[scott vroom]

A multi tool will handle it quickly but the others have good hand tips....BEST to sand prior to assembly..

As I mentioned above, I'm working with interlocking dado joinery on wall shelving. I'm finding this type of joinery requires post assy wood filler....pre-assy sanding doesn't solve that problem. I'll post pics later todat, maybe that will clarify what is is I'm stuck on.

Thanks for all the helpful responses!

[John Bomment]

Festool makes a linear sander,
the 567852 LS 130 EQ Linear Sander

http://www.domainindustries.com/media/catalog/product/cache/1/image/9df78eab33525d08d6e5fb8d27136e95/F/T/FT-567852-001_4.jpg

[scott vroom]

John, the linear sander solves the groove problem, but I'm dealing with grain that is perpendicular to the corner and that linear sander would cut cross grain.




Festool makes a linear sander,
the 567852 LS 130 EQ Linear Sander

http://www.domainindustries.com/media/catalog/product/cache/1/image/9df78eab33525d08d6e5fb8d27136e95/F/T/FT-567852-001_4.jpg

[John Bomment]

Sorry Scott,
I missed that you mentioned the 130 in your second post.