How do you plane the top of a box flush

[jesse ross]

Are there any tricks to planing the top of a box flush?
In this case I made a dovetailed box, and glued it up with bottom and top attached. The idea being to saw off the top and thus create the lid.

Unfortunately, there was a little rocking during four runs through the table saw and now I have some rough edges to flush on top and bottom. I've run into this issue of flush planing four adjacent edges before on picture frames and always get stuck with sloped edges, tearout when going from longrain to cross-grain, etc...

Is there a correct way to do this?

Box pic prior to cutting, for reference405511

[Jim Koepke]

Make sure the plane blades are as sharp as can be. Take very light cuts to help reduce tear out. A scraper may also help.

A recent FWW tip was to make blocks with ribs on them the same thickness as your saw blade. Then as the box is cut these can be slipped into the kerf and held in place with rubber bands to help keep the box from flexing while sawing.ß

jtk

[Phil Mueller]

Another method I use is to adhear some 150 grit sandpaper to a flat surface (plate glass, granite, table saw, etc), then sand the top and box until they mate. I put a pencil mark all around the edges to be sanded to know when I’ve gotting it all flat. I rotate the pieces after a number of strokes on the sandpaper to make up for any uneven pressure. Go light on the pressure and be careful not to lean the pieces as it is very easy to round over the corners.

Very nice looking box, by the way!

[Mike Henderson]

Another method I use is to adhere some 150 grit sandpaper to a flat surface (plate glass, granite, table saw, etc), then sand the top and box until they mate. I put a pencil mark all around the edges to be sanded to know when I’ve gotten it all flat. I rotate the pieces after a number of strokes on the sandpaper to make up for any uneven pressure. Go light on the pressure and be careful not to lean the pieces as it is very easy to round over the corners.

Very nice looking box, by the way!

This is what I do, also. I have some sandpaper from those giant belt sanders that I cut and glue on to MDF (with glue that has no water in it). The MDF is perhaps 30" by 30". I move the box over the sandpaper essentially as described my Phil.

The standard way to make a box with a lid is to make a closed box and then cut the top off. You'll never cut perfectly, no matter what technique you use (bandsaw, table saw, hand saw). To get a good fitting top, you have to sand the upper surface of the lower part of the box, and the bottom of the top. Done correctly, you can get a top that fits exactly.

I did a tutorial on making a jewelry box (http://www.mikes-woodwork.com/BoxTutorial.htm) and in that tutorial I have a picture of one of my big sanding boards. I think the sanding board is on the second page.

Mike

[Mike Henderson]

A recent FWW tip was to make blocks with ribs on them the same thickness as your saw blade. Then as the box is cut these can be slipped into the kerf and held in place with rubber bands to help keep the box from flexing while sawing.ß

jtk

I use spacers that I put into the saw kerf when I saw the top off of a box and I've never had one come out perfectly.

Another approach I tried is to not cut completely through the sides - just leave a very thin piece of wood holding the top on. Then, after you've cut all four sides, use a knife to finish the cut. That has not given me perfectly fitting tops either. I still have to sand the interface.

I don't see any way to get a perfect match using a hand plane. The sanding board is the only thing that has ever worked for me.

Mike

[Here's a couple of blade spacers that I use - you need three of them when cutting the top off of a box. The mahogany one is for a standard thickness blade and the walnut one is for a very thin blade that I have and often use to cut the top off of boxes. I use that thin blade because it removes less wood, leading to a better grain match between the top and bottom. For a very thin kerf, I've hand cut using a Japanese saw, but that doesn't give a perfect surface, either.

The first picture is a top view and the second is a somewhat side view. The best way to make these is to cut a groove with your blade and then make a piece of wood that will just fit into the groove. That will match the width of the kerf of your blade.]

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[lowell holmes]

I would try a scraper and or a pad sander. Maybe both could be used.
Or, http://www.leevalley.com/us/wood/Search.aspx?action=n

[Rob Luter]

A method I've used successfully many times is to set the depth of cut on your table saw about 1/32" short of cutting all the way through. Finish the cut with a stanley knife. The feathery remnants usually will just snap off. If not. use a small block plane set for a super light cut to bring the surfaces flush. Use the sandpaper trick if you need to true things up, but I've never had to.

[Robert Hazelwood]

I've only done this kind of cut on a bandsaw so I've always had to clean up with a plane. You need to be very sharp, have a light depth of cut so that you can easily control the tool, and it's a good idea to set the chipbreaker close. Then I basically drive the plane around in a circle. Start out on one of the long sides, and as you get close to the corner skew the plane to about 45 degrees, all the while keeping the plane in the cut. Make the corner while skewed like that, and as you get onto the next side straighten the plane out again, then skew again as you come to the next corner. The idea is that you are always skewed when you are cutting crossgrain. That minimizes tearout/fuzziness. Once you get a full shaving all the way along the top length of the box it's usually good to go. You can set the top on the bottom and see if there's any light. If there is, then take a few shavings off the high corners. Not that much different than jointing an edge. If you are very sharp and take light passes, you can get a good enough finish that you won't need to sand.

[Warren Mickley]

With a marking gauge or panel gauge, mark the box with two lines 1/8 inch apart. Use a back saw to saw between the lines. Then you still have the marked lines on both bottom and lid, and can plane to the lines.

By the way, it is nice to make a wide dovetail pin at the place where the box is to be sawn apart so that you have half pins left when you do the sawing. A 5/8 wide pin would yield a 1/4" half pin for the top, a 1/4" half pin for the bottom, and 1/8 for kerf and cleaning up. Plan ahead.

[glenn bradley]

If possible, watch this video (https://www.finewoodworking.com/2012/08/07/3-low-stress-glue-up) at about 6:53. Garrett just planes right around the outer edges. I have seen him do this in other videos and picked up this technique for leveling drawers and so forth.

[Derek Cohen]

Glenn, for carcases, such as the one in the Garrett video, I would also plane around the circumference. However, I would not do it that way here.

The fitting of a door to the front is not as critical as fitting lid to a box where the sides must not show a gap. The box is required to be exactly parallel on four sides with the lid. All four sides of the box need to be coplanar. All four sides of the lid also need to be coplanar. To do this, I would either: (1) rub the edges on a flat surface to find the high spots, and then plane them down, or (2) rub the edges on sandpaper and flatten them that way.

Regards from Perth

Derek

[Lee Schierer]

When cutting the top off a box, raise the blade above the table 1/32 higher than the thickness of the side. Then cut through the two short sides of the box first. Then lower the blade so it is 1/64" to 1/32" lower than the thickness of the side. Cut one long side with this lowered blade. Then raise the blade back up so it will cut all the way through and cut the fourth side. Use a sharp knife to slice through the thin material you left on the one side of the box and sand or plane it smooth.

[Edwin Santos]

For a smaller item like this I use method mentioned already of fixing sandpaper to a flat surface and lapping. Another common way of doing this is to make a long sanding flat sanding block by wedging an appropriate sized piece of wood inside a sanding belt.

[steven c newman]

405544
Sometimes a double bead can help guide the saw...
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To where I saw between the beads..
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Plane is long enough to reach everywhere, evenly..
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Corner joints were full blind, mitered box joints..
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Add a pair of hinges, and some finish...
Joints?
405549
Opened..
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Closed up for a dry fit.

[Jim Tobias]

If you make a lot of boxes, and I make a lot of boxes, it may be worth it to take a look at this idea. I came up with this while I was trying to get some boxes finished for an upcoming show and had shoulder issues ( which eventually led to shoulder surgery) and could not use the "sandpaper on flat surface idea" which I've used for years. At first, I experimented with a $28 sander from Harbor Freight before investing in a better Makita Sander. The Harbor Freight sander worked OK but vibration and noise was an issue for me. I made a platen from Baltic Birch 1/2" ply and covered it with adhesive hook/loop material(from Klingspor, I think). Once I had decided that the concept was good enough to pursue I made a "holder" that I could clamp in the bench vice to secure the sander in place. I matched up holes in the platen for large sheets of sandpaper so I could use dust collection on the Makita.
It actually gave me a very flat surface and by starting out with course grit and proceeding to finer grits It allows the endgrain to really show when you open the box green to show when you open the box.
I realize that unless you are making a lot of boxes, this is over the top time and cost wise. But, for me, it was a timesaver and gave good results.
Pictures are of HF sander , a rough grit sanding on an edge and then the latest version of the Makita sander set up.

Jim
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[Tom Trees]

It seems you need to be a member to watch Garret's video.
Here's Rob demonstrating this at 7 mins into his video..

https://www.youtube.com/watch?v=xInTrbqGva0

Good luck
Tom

[Derek Cohen]

Tom, as noted re Garrett's video, Rob is not planing mating surfaces.

Regards from Perth

Derek

[Pat Barry]

Use the table saw and rip fence to make trim cuts, taking off just a little with each pass. After doing this to get things basically flat you can finish by sanding if need be.
I

[jesse ross]

Thank You everyone for the replies!

I ended up sending the box top and bottom through the planer (skewed to avoid tearout) and taking very light passes off the mating edges, to do the majority of the work. Then I laid out strips of 150 grit psa sandpaper on a granite block and sanded the edges smooth. Worked like a charm with no rounding over.

In the future I think I will try some of the shimming techniques described here, maybe in conjunction with sawing close to, but not through, the box, and finishing off with a knife or japanese pullsaw, followed by sanding and/or light planing. Also, I think my table saw insert was sitting ever so slightly below the plane of the table, and that prevented the box from riding smoothly through the cuts. I'll do this on a sled next time.

The box got smaller through all this trial and error, but at least now it's seamless, and I've learned alot. I just couldn't get it out of my head that I Should be able to do this with a plane, even as my results proved conclusively otherwise.

Jesse

[Phil Mueller]

Glad it worked out for you Jesse. Yes, I too, have made a few boxes smaller than the original plan! On the times I’ve really botched the sanding with a dip in one corner and don’t want to keep sanding it more, put a small chamfer around the outer edges of the both the top and bottom. It’s actually not a bad look and can hide a few evils when necessary.

[Phil Mueller]

Thanks for sharing that Jim. Looks like a nice evening project. I have an old 1/4 sheet Bosch sander I may have to try that with.

[glenn bradley]

Glenn, for carcases, such as the one in the Garrett video, I would also plane around the circumference. However, I would not do it that way here.

The fitting of a door to the front is not as critical as fitting lid to a box where the sides must not show a gap. The box is required to be exactly parallel on four sides with the lid. All four sides of the box need to be coplanar. All four sides of the lid also need to be coplanar. To do this, I would either: (1) rub the edges on a flat surface to find the high spots, and then plane them down, or (2) rub the edges on sandpaper and flatten them that way.

Regards from Perth

Derek

Thanks Derek. Excellent point on the gap consistency. That is just why I have a piece of melamine with sandpaper spray-adhesive attached :)

[Rob Luter]

There's another method I learned in college. During a design studio class we were discussing assemblies, and particularly the mating surfaces of different parts. The context was consumer products but it's still applicable. The gist of the lesson was that if achieving a seamless mating surface was all but impossible due to part tolerances, manufacturing processes, dissimilar materials, etc.; don't even try. Instead build in a "reveal" feature that hides the sins and makes it look like you intended it to look just the way it looks.

I've incorporated tiny chamfers or rabbets between box tops and bottoms, effectively hiding the seam behind a design element. The feature creates a nice shadow line and can also offer a thumbnail grip for opening the lid. Most snap together plastic assemblies use this approach. Take a look at the case of almost any piece of consumer electronics or computer gear for an example.

[Kim Gibbens]

Is it long enough to go through a drum sander? Seems like something I would try. Very light pass with your highest grit. I've never done that, it's just an idea that popped up reading this thread. I'm probably way off base , so someone can come along and tell me it doesn't work and I would probably NOT try it.

[Joe Bradshaw]

I use my drum sander on all the boxes that I make. On the shorter boxes, I will hot glue longer strips of wood to the sides of the boxes to get enough length to pass through the sander.
Joe

[Robert Hazelwood]

Sounds like the consensus is that it's virtually impossible to do with a hand plane? I have to disagree. It is not much different than jointing for a perfect glue line on a panel edge, you are just going around the perimeter of a box instead of in a straight line. Plane a little, then put the top on the bottom and check for gaps. Note the high spots, plane those down. If one of the edges is sloped, you correct it just like you'd correct an out of square edge when jointing for a panel glue up. In fact, if you use a plane long enough so that it can always be in contact with two sides of the box, then any sloping issue will tend to correct itself. I like to use a #8 or 5-1/2 for this reason. But I'm pretty sure I could do it with my #3.

If you have a sandpaper lap big enough, then of course that will guarantee a good result. But it's a little annoying to set up and then clean the lap after I'm done (at least in my experience PSA paper tends to be tenacious and hard to remove). I don't have a drum sander, and don't really want one (mostly because I am out of space for new tools). If a plane is sharp and ready to go, I'd rather be able to use that.

[Mike Henderson]

Sounds like the consensus is that it's virtually impossible to do with a hand plane? I have to disagree. It is not much different than jointing for a perfect glue line on a panel edge, you are just going around the perimeter of a box instead of in a straight line. Plane a little, then put the top on the bottom and check for gaps. Note the high spots, plane those down. If one of the edges is sloped, you correct it just like you'd correct an out of square edge when jointing for a panel glue up. In fact, if you use a plane long enough so that it can always be in contact with two sides of the box, then any sloping issue will tend to correct itself. I like to use a #8 or 5-1/2 for this reason. But I'm pretty sure I could do it with my #3.

If you have a sandpaper lap big enough, then of course that will guarantee a good result. But it's a little annoying to set up and then clean the lap after I'm done (at least in my experience PSA paper tends to be tenacious and hard to remove). I don't have a drum sander, and don't really want one (mostly because I am out of space for new tools). If a plane is sharp and ready to go, I'd rather be able to use that.

I'm sure it's possible to plane a box flat. But I'd probably wind up with a pancake as I kept taking just a bit off here and there to try to get everything flat:).

While it may not be traditional, a sanding board is much easier for me to use. I put a pencil or chalk line around the surface and then move the box or top over the sanding board until the mark is gone from all parts of the box or top. If the sanding board is flat, and if I was careful in moving the box over the surface, the top of the box will be flat and the sides will not be angled in or out. Same for the top of the box.

Here's a few sanding boards I've made. I like to put a coarse sandpaper on one side and a finer sandpaper on the other side. I get one of those big belts that the belt sanders use (like the Timesaver). I found some on Craigslist that someone was selling cheap because the glue holding the belts together had failed (they were new but had been in storage for years and the glue failed).

In gluing the belt to MDF, do not use a water based glue - it will cause the MDF to warp. I use 3M spray adhesive and spray the MDF and the belt. Apply the belt like Formica.
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I teach a box making class and use this with my students. Storing the sanding boards is not a problem - just lean them against the wall or your bench.

Mike

[Brian Holcombe]

Not terribly difficult to plane the gap tight. Just take off where you need it removed. Fit the hinges afterward and set their depth not to the leaves but to a zero gap fit (or nearly, I usually shoot for a few thou gap) to make life easier.

[Don Dorn]

I also move the plane around the box, ala Paul Sellers method. Whatever sanding that is left is minimal.

[Derek Cohen]

I think that both Brian and I are indicating that planing around the box comes later. Finding (rubbing) the high spots and planing only those comes first.

Think of jointing an edge. Remove the high spots before planing the length.

Regards from Perth

Derek