Box building tips

[skatz]

I wondered if all you accomplished wood workers out there have tips for building good boxes.

I just made a set of boxes over the weekend, and once again am dismayed by my carpentry skills. I think I cut the parts accurately enough, and cut biscuit slots to join the panels (**** joints), but the biscuits seem to cause a little misalignment and the whole thing doesn't fit together real well. Maybe I shouldn't use these?

So how do you guys build your boxes, what works, what doesn't? Do you reinforce the joints with biscuits or dowels or dados or miter the joints or just glue them up? Frankly, I think I did better with just glue!

[romanbednarek]

I wondered if all you accomplished wood workers out there have tips for building good boxes.

I just made a set of boxes over the weekend, and once again am dismayed by my carpentry skills. I think I cut the parts accurately enough, and cut biscuit slots to join the panels (**** joints), but the biscuits seem to cause a little misalignment and the whole thing doesn't fit together real well. Maybe I shouldn't use these?

So how do you guys build your boxes, what works, what doesn't? Do you reinforce the joints with biscuits or dowels or dados or miter the joints or just glue them up? Frankly, I think I did better with just glue!

I have a pretty straightforward method for making speaker enclosures which involves buying shelving MDF (12" wide by 4' long or 15" wide by 3' long) that I rip to width with my brother's (cheap) table saw and then cut to length using a circular saw with a jig that I made which ensures nearly perfect 90 degree cuts.

When it comes to gluing things together I dry clamp the pieces together first, then drill small guide holes and insert small finishing nails (but ensure that they don't go all the way in so that I can pull them back out easily). When I glue the cabinet together the finishing nails act as a guide to ensure that everything lines up perfectly, then once the glue is dry (30 min or so) I unclamp and remove the nails.

If you look at the blueprints for my projects at the link below you'll notice that I usually cut the pieces of MDF so that all of the center boards are the same width (baffle, back panel, top/bottom panel and internal bracing). With this configuration I am able to cut all of those panels to the same width using the table saw. This also sets up for my gluing process where I'll lay one cabinet side piece of MDF on the table as a guide and glue the inner frame which includes the front baffle, back panel, top panel and bottom panel (ensuring that it lines up well with the side piece and using wax paper so that excess glue doesn't affix this frame to the side piece yet). I'll then glue that frame to one side piece and then add the internal braces and glue them next. Finally the other side goes on and the cabinet is done.

I got so comfortable with this process that I pretty much carried it through most of my projects and sometimes my cabinet dimensions were somewhat dictated by the sizes of MDF shelving boards and the most efficient use of them. I know that everybody does things differently but this process is what evolved for me, a novice woodworker with limited tools.

The tip, that is buried in all of the text above, that would probably help you out the most is the use of dry-clamping and guide nails when gluing.

[brianwalter]

Skatz, I think Roman's suggestions are pretty good, but I also think that getting all of your pieces to the correct width and cut off square to the correct length is the biggest problem most beginners have. Roman's tip of using a jig that allows him to cut his pieces nearly perfectly square may be the most important piece of advice he mentions. If your cuts aren't square everything errors tend to multiply and nothing will line up correctly. This is one of the reasons I aways suggest the beginners use a cross cut sled with their table saw, most miter gages simply don't have long enough guide bars to allow accurate cross cuts on wide boards.

If you don't have a table saw, then use a circular saw along with a saw board or similar jig with which includes a T-Square type fence to square up your cuts. This is critical in getting a good fit. It's amazing how much just a 32nd of and inch off over say 10" can mess up your alignment when trying to get everything to fit together correctly.

Brian Walter

[Æ]

Practice. The more you practice, the better you'll get.

Accomplished woodworkers didn't get there by not making mistakes!

I certainly wasted plenty of MDF.

Most of my first projects were buttt joints, and they usually ended up misaligned and out of square. I now prefer a buttt joint with a rabbet. So that way everything self aligns. One thing that you can never have too many of is clamps. Clamps and clamps and more clamps. I especially like web clamps (straps).

I wondered if all you accomplished wood workers out there have tips for building good boxes.

I just made a set of boxes over the weekend, and once again am dismayed by my carpentry skills. I think I cut the parts accurately enough, and cut biscuit slots to join the panels (**** joints), but the biscuits seem to cause a little misalignment and the whole thing doesn't fit together real well. Maybe I shouldn't use these?

So how do you guys build your boxes, what works, what doesn't? Do you reinforce the joints with biscuits or dowels or dados or miter the joints or just glue them up? Frankly, I think I did better with just glue!

[jim85iroc]

The sequence in which you do things is very important. Having perfectly parallel, straight cuts isn't always necessary, though it certainly doesn't hurt. Thinking your way through the process of cutting the panels will take care of your accuracy problems in some cases, and in other cases will make them less important. There are a million ways to accomplish this, but here's one way. Even if you don't follow this step-by-step, it illustrates that in many cases, you can work around your limitations.

1. Set table saw fence to the internal height of the enclosure (external height minus 2x panel thickness), and cut your back panel and side panels.

2. Set table saw fence to internal width of enclosure (external width minus 2x the panel thickness) and cut the back panel and a couple scrap pieces. At this point your back panel should be complete.

3. Set table saw fence to the depth of your enclosure minus the front baffle thickness, and cut your sides. Your sides should be done now.

4. You can attach one side to the back, then use your scrap pieces as spacers at the front of the enclosure when you glue up the other side to the back. This will help keep everything square, or at least perpendicular.

5. Now it's time for the top & bottom. All you need is one straight edge that you line up with the front line of the 2 sides. If the top hangs over the sides & back, you can trim them flush with a router, which makes those edges completely unimportant.

6. Once the top & bottom are done in that way, you can slap an oversized baffle onto the box and trim all the way around it with the flush trim bit.

Your final product might not be 100% square, but it'll look like it is, and you won't have any gaps or overhang on any of your panels.

If you don't have a table saw, you can use a circular saw with a fence attachment to accomplish the same thing:


You can also make the first cut with a circular saw and any kind of flat guide, then attach a similar fence to a router with a straight bit to get the 2nd parallel cut. You can even make your first cut with a router & a flush trim bit and a straight edge.

There are a million ways to skin a cat, you just need to use some ingenuity to help overcome your limitations.

There are a few techniques used above that will serve you well:
1. Economy of cuts. When you set the fence on your cutting tool, cut EVERYTHING that needs that dimension at once. Back, sides, whatever. If you set the fence to that same spot 2 separate times, you'll wind up with 2 separate sizes and your stuff won't fit.

2. Whatever the tool, buy or build a device that allows it to follow a straight reference.

Here's a neat attachment for the router that you could make yourself. It works the same way the one shown on the circular saw above works:


3. Think your way through your assembly order. Doing this, when combined with a few straight cuts, will eliminate the need to have EVERYTHING straight so long as you have a flush trim bit for your router.

You can build an entire enclosure with nothing more than a router, a flush trim bit, and a straight edge to follow (and a circle template to follow for the driver cutouts). All of the other tools just help simplify things.

[williamrschneider]

I've used biscuits on my last two builds and love them. I've also used screw-and-glue assembly too with good success. I haven't tried rabbets though, although that should work very well also.

I think others have hit on the most important thing - make accurate cuts first, then assemble using whatever method you choose. You should have a combination square to judge ...well, ...squareness of the cut pieces. Accurately measure the cuts to see if you are within your goal and if parts are truly square.

Using a good straight edge clamped to a sheet of MDF and your circular saw, you should be able to hit within 1/32" easily. If you have the means to measure more accurately than a tape measure (i.e. using a caliper to set the cutting guide, and bracing the center of the straightedge against deflection), you can get to within 0.010" of your target.

If you are using a table saw, does it cut square? I've spent hours adjusting mine to where cuts are smooth, square, and almost exactly the length I need.

Cutting and assembly are the easy parts. Setup is where I spend most of my time.

[waynew]

For the beginner, I will give away this highly secret, copywritten, patent pending, trademarked advice.

1. Buy a router and a really good flush trim bit

2. Oversize all of the edges that show edgegrain about 1/8", glue up box as closely as you can (I like to make the sides and internal braces all the same depth to "set the dimension of the enclosure"), allow to dry for 24 hours, come back and flush trim the excess and poof...perfect joints! The amazing thing about this - if you are out of square just a tad, no one but you will ever know, unless you run into some really good woodworker!

3. Next, You can sell these for a modest profit, buy a really nice table saw and get repeatable accuracy with a good fence. Build cross-cut sled per Brian Walter's suggestion, and don't forget to add/subtract for glue thickness (usually around 1/64 or so).

If you ask me if this is how I do it, I would tell you that sometimes biscuits are too small or too big and cause problems, sometimes the wood is warped and a rabbet gets out of alignment, sometimes your 45 tilt is off just a touch and your edges don't line up perfectly. Sometimes, it's just easier to b_u_t_t Joint the box with plenty of glue and waste a bit of MDF!

Don't let the joint get you down brother!

Wayne

[skatz]

Thank all of you who have responded so far.

I guess I didn't make myself completely clear.

I cut all the pieces (cutting all the parts of same dimension at the same time as suggested), and was satisfied that they were all accurately sized and square. It was when I got to the biscuits that I ran into trouble and I'm not entirely sure why, although I can guess.

The biscuit jointer seems to be a hair off, that is, on 3/4 material the slot is a little closer to one face than the other, just a tiny amount. That means to get a corner put together correctly, the reference for each slot needs to be the same, ie, outside face and outside edge used as the reference point, and I may have made some errors in doing this. Some of my slots seemed to be a tiny bit crooked, which has got to be my error in not getting the tool situated correctly to make the slot.

Now, the boxes are not glued together, just dry fit with biscuits. I may do better to remove them and just glue up with corner clamps and guide nails, as somebody suggested, but I wanted to see how other people do it to.

This has been instructive; I hope more chime in with their methods. Thanks.

[davepellegrene]

Thank all of you who have responded so far.

I guess I didn't make myself completely clear.

I cut all the pieces (cutting all the parts of same dimension at the same time as suggested), and was satisfied that they were all accurately sized and square. It was when I got to the biscuits that I ran into trouble and I'm not entirely sure why, although I can guess.

The biscuit jointer seems to be a hair off, that is, on 3/4 material the slot is a little closer to one face than the other, just a tiny amount. That means to get a corner put together correctly, the reference for each slot needs to be the same, ie, outside face and outside edge used as the reference point, and I may have made some errors in doing this. Some of my slots seemed to be a tiny bit crooked, which has got to be my error in not getting the tool situated correctly to make the slot.

Now, the boxes are not glued together, just dry fit with biscuits. I may do better to remove them and just glue up with corner clamps and guide nails, as somebody suggested, but I wanted to see how other people do it to.

This has been instructive; I hope more chime in with their methods. Thanks.

Just a thought.
You could run the biscuit jointer back into the slots, on the boards that have the slot on the end, from the opposite side. That is if you are not to far off center with the slot. When you apply the glue the biscuits will swell. This should give you enough play to allign the joints. Just use plenty of glue.
Dave

[williamrschneider]

Sounds like biscuit cutting is the problem area. I disliked balancing the cutter on thin edges to make face cuts in particular.



I made a jig to ensure better accuracy. I've shown some details of the jig in a thread called "Bill's Overnight Sensations Build Diary", so I'll just post one of the photos here...



More photos and dimensions can be found in that thread. The jig makes it simple to get good cuts where you want them.

It won't work making face cuts in the middle of a large panel though. A good example of that might be shelf braces in a floorstander like the Zaph ZDT3.5 shown below.



I aligned the two cabinet sides to be cut side by side so that the straightedge spanned both simultaneously. The combination square shown was used to set distance to ensure both sides of the straightedge were exactly the same.

That allowed me to get things close enough that everything just snapped together like a Lego toy...



Don't forget to tune-up your biscuit cutter so that it's square to itself and makes cuts where you want them. I had to add some washers as shims on my PC cutter to get the baseplate to be square to the face.

[LouC]

Thank all of you who have responded so far.

I guess I didn't make myself completely clear.

I cut all the pieces (cutting all the parts of same dimension at the same time as suggested), and was satisfied that they were all accurately sized and square. It was when I got to the biscuits that I ran into trouble and I'm not entirely sure why, although I can guess.

For 3/4" (or thicker stock) forget the fence on the biscuit joiner. Just use a flat table. Mark everything on one side. Do all the edge slots with the joiner on the table and the MDF on the table.

For face slots, you just need something to keep the panel perpendicular to the table. Again just put the joiner on the table and cut. When you assemble the box, make sure all the pencil marks are on the inside of the box. As long as the joiner blade is parallel to the base, you are good to go.

[williamrschneider]

...make sure all the pencil marks are on the inside of the box

That's a really good point! If someone switches between outside and inside, the inherent registration provided by a biscuit cutter is gone.

[arlis_1957@yahoo.com]

skatz, waynew is way right. an end bearing flush cut bit is your friend.
when i put together a box i make sure that my back is square and i put the back on its back and start glueing and putting brads every 8 inchs or so once everything is tight, i tighten the clamps.

[skatz]

Sounds like biscuit cutting is the problem area. I disliked balancing the cutter on thin edges to make face cuts in particular.



I made a jig to ensure better accuracy. I've shown some details of the jig in a thread called "Bill's Overnight Sensations Build Diary", so I'll just post one of the photos here...



More photos and dimensions can be found in that thread. The jig makes it simple to get good cuts where you want them.

It won't work making face cuts in the middle of a large panel though. A good example of that might be shelf braces in a floorstander like the Zaph ZDT3.5 shown below.



I aligned the two cabinet sides to be cut side by side so that the straightedge spanned both simultaneously. The combination square shown was used to set distance to ensure both sides of the straightedge were exactly the same.

That allowed me to get things close enough that everything just snapped together like a Lego toy...



Don't forget to tune-up your biscuit cutter so that it's square to itself and makes cuts where you want them. I had to file some washers on my PC cutter to get the baseplate to be square to the face.

You know, I saw that jig in your thread, don't know why I didn't think of it, maybe too much in a rush to get these done. Now I see the wisdom in it.

[skatz]

For 3/4" (or thicker stock) forget the fence on the biscuit joiner. Just use a flat table. Mark everything on one side. Do all the edge slots with the joiner on the table and the MDF on the table.

For face slots, you just need something to keep the panel perpendicular to the table. Again just put the joiner on the table and cut. When you assemble the box, make sure all the pencil marks are on the inside of the box. As long as the joiner blade is parallel to the base, you are good to go.

That's exactly what I did this time. I'm afraid I may have reversed some of the board and lost the reference point. I have the same slot cutter. I don't know of any way to adjust it and make it "square to" itself as Bill suggested, doesn't look like there is any adjustment. I'm going to make a few test cuts in scrap just to see how well it all matches up. If it does I'll know I'm the guilty party here (I think thats a safe bet).
Since you use biscuits, how weak would the joints be if I leave the biscuits out and just glue them? I could put in some corner blocks for strength.

[rwrankin]

I had the same problem you are experiencing when I first started using a biscuit joiner years ago, and it was exactly the problem Bill illustrated.


I built a similar jig after my first go round and have been using it for years now with repeated success on many projects, loudspeaker and otherwise.

Bill is right on the money with his advice.

[Ryan_M]

I use the method LouC describes and it's perfect. Though I use my Table saw as a able and my fence as the backstop but it's close enough. If you want to leave a bit ov overhang to be flush trimmed you can put something under the biscuit joiner when cutting the biscuits for that piece. For instance if you place a piece of carboard from a cereal box your joint will be ~1/32" proud which is easily trimmed or you could probably just sand.

skatz, the cutter is most likely square - barring manufacturing defect or if the tool was dropped. Probably just lost the reference side. I mark up my pieces of wood with one of those clicky pencils, indicating reference sides and little notes and stuff. I caused myself a lot of grief in the past before I started doing that. I don't think you'll be losing too much in the way of strength if you just leave the biscuits out like you're suggesting.

Alan, Is that drop ceiling tiles in your boxes?

[Wolf]

That's exactly what I did this time. I'm afraid I may have reversed some of the board and lost the reference point. I have the same slot cutter. I don't know of any way to adjust it and make it "square to" itself as Bill suggested, doesn't look like there is any adjustment. I'm going to make a few test cuts in scrap just to see how well it all matches up. If it does I'll know I'm the guilty party here (I think thats a safe bet).
Since you use biscuits, how weak would the joints be if I leave the biscuits out and just glue them? I could put in some corner blocks for strength.

How LouC does it is how I do it with my Ryobi. Flat table gives same distance from edge every time. I just use the table-saw as a reference plane, and do it free-hand.
Later,
Wolf

[aaronarnold]

It's been hit on a bunch. Use a quality flush trim bit and a router table if possible(the router table takes the bobbles out, especially around the corners). If you are a stickler for craftsmanship you could always use biscuits. Just adjust the biscuit cutter so that panels that can be recessed are recessed beneth the edge of the panels such as your baffle. By using buscuits you ensure a square overhang and then tidy up the job with a flush trim bit. When cutting your boards, come with a plan and only set your table saw once for every length of cut. I like to cut a little extra scrap especailly for larger boxes so that I have spare pieces to help line everything up.