Construction method

[Zozobra]

What's everyone's preferred construction method for building cabs/headshells?

I'm weighing up the benefit of the following methods:
Finger joint
Dovetails
Dowelled butt joint
Pocket screwed butt joint

I very much suspect that finger/dovetail joints will give the strongest construction but they're limited by what jigs you have to hand and they have a far scope for error to mess things up. Pocket screwed butt joints look to be the easiest and most flexible but wont be as strong or as pretty as the finger/dovetail joint.

Thoughts, opinions and experiences much appreciated!

[GregS]

My preferred method is butt joints which are reinforced with 2 x 2 braces which are both glued and screwed in with flooring screws. I use the 2 x 2 bracing around the front and back edges of the cabinet as well which also serve to anchor the baffle and back panel. I use 3/4" plywood for all panels.

The cabinets are rediculously strong - overbuilt if anything. especially when the front and back panels are attached. The only way I can see the cabinet collapsing is if either it's thrown off a skyscraper building or put in a hydraulic press used to crush scrap cars. The point is, if done properly, strength is a non issue with butt joints that are reinforced with bracing. The 2 x 2 I use is probably overkill as well. Smaller lumber would probably be adequate.

The way I see it there are other advantages/disadvantages to butt joints, box joints / dovetails.

The disadvantage of reinforced butt joints is the bracing takes up volume in the cabinet and adds weight.

The advantages of dovetails are they look nice if done well with an uncovered cabinet. There are other design possibilities as well without the large bracing. For example, head cabinets with see through plexiglass or cage front / backs. The bracing would not look right.

Greg

[Zozobra]

Thanks. I think I may prototype a few different dimensions using pocket screws and then build the real deal with finger joints with an appropriately sized jig.

[cminor9]

I use finger joints. They aren't hard to cut. I have made them anywhere from 3/4" to 1.25" and they have worked well. You don't really need a special jig. Set your table saw fow 3/4" depth, and make the cuts into the ends with the table saw. Then get a jigsaw and cut them out. It's fast, easy, and if you are precise it gets nice tight joints.

If you are covering with tolex, don't waste your time with dovetails. Box joints (aka finger joints) are just as strong. Get some good glue and a bar clamp, too.

You can even add dowels for added strength if you want. I have done that on a particularly large cab.

Good joinery is all about surface area. Increase the surface area, increase the joint's strength.

This eliminates the need for bracing, which makes for a lighter cab.

[Bill Moore]

I have built a few combo cabs using bisquits. The tool was a little pricey, but it's not hard to get a great butt joint, once it's covered, looks like any other cab.

[Diablo]

I enlisted the woodworking skills of a friend. He used 3/4 inch baltic birch ply with box joints and epoxy glue. The head cabinet is hella strong and was almost too pretty to cover in tolex. I did the tolex covering and made it easy to cover at the corners by using steel corner guards.

[J M Fahey]

Hi cminor.
Sounds interesting, could you provide a couple pictures?
Of the woodwork and tools used.
Thanks.

[nashvillebill]

Lately I've been making some drawers, which bear quite a bit in comon to amp cabinets. So far I've tried several methods, here's my take on them:

Dovetail joints: I've got the Rockler jig and it works pretty well. Slightly time consuming in setup, but its a strong joint. You'll have a lot of money tied up in router plus jig. Pros: very tight fit, very strong, looks good. Cons: not supposed to work on plywood (I haven't tried it), boards should be planed for best fit, width limited to size of jig (12"), lots of sawdust. (The dovetail joints cut out a ton of wood hence lots of sawdust) The Rockler jig can cut box joints too by the way.

Biscuit joints: Easy to do with the biscuit joiner. Pretty strong but not as strong as the dovetail I think. Pros: fast, easy. Cons: I've had trouble with biscuits in thinner material (1/2" thick), as the biscuit swells, it wants to break out the surrounding wood. Tool is pricey.

Locking rabbet (double dado) joint: This was recommended for drawer fronts so I tried it. Joinery | Lock-Rabbet Drawer Joint | Setup was a little tricky but I made three complete drawers in one evening. Hardest part other than setup is the dado where the board must be held vertically (I don't have a mortise and tennoning jig, so I made a homemade fixture). Pros: once setup is done, it went well. Really strong and looks good. Cons: setup. Must have a good dado blades. Boards must be planed flat for a good fit.

Next up--I've got a drawer lock joint router bit on the way from MLCS, it's similar to the last joint but setup should go faster MLCS How to Make a Drawer Lock Joint - YouTube

[cminor9]

Hi cminor.
Sounds interesting, could you provide a couple pictures?
Of the woodwork and tools used.
Thanks.

Sure, here is a pic: 2x12 black tolex | Flickr - Photo Sharing!

I cut the ends 3/4 deep using a table saw, and then used a coping saw to cut across them to make the cutouts. Notice the fingers stick out just a bit over the edge of the wood. I hit that with a flush router bit. Glued those joints up, and clamped them. Then I drilled the dowel holes and pounded in some 3" oak dowels, drilling a small hole at the end to vent them. For the top, I did the dowels, clamped the cab horizontally with a bar clamp, and then put about 75 lbs on top. That's one strong cab.

[Bill Moore]

That really does look strong! Would you call that dowelled finger joints?

[cminor9]

That really does look strong! Would you call that dowelled finger joints?

Doweled finger joints sounds good to me! Good joints are all about surface area. I figure the dowels buy me some extra surface area. Since the fingers are relatively wide (1 1/4 or 1 1/2") I figure a little extra help is good.

[imaradiostar]

Dunno if it helps but here's a link to an old thread with pictures of the jig I built for myself. It works really well.

http://music-electronics-forum.com/t21944/#post183109

Jamie

[cminor9]

Nice jig! I wanted to build something like that for my table saw, but I need a dado set. Which is why I had to use a coping saw. But a router setup like that will make cleaner cuts than either. I'll bet that'll work well in pine, but how's it do through plywood? Slow going?

[imaradiostar]

Nice jig!... I'll bet that'll work well in pine, but how's it do through plywood? Slow going?

Thanks! I wish I had more time to use it! I currently have about 5 cabinets in various states of non-completion but the finger joints are lovely. Truly, even with plywood it works very well. I have a friend that builds guitars and he came over to use it for some cabinets and he really liked it too.

I went to the table saw/dado system because I wasn't getting very clean cuts with the router- but that was just my experience, don't take that as gospel. You can probably see in the pictures that the comb is from the Shopfox router dado/finger joint jig. I have the harbor freight jig (more or less the same tool) and while it's fine for small drawers and dovetails I didn't find it to be a good solution for any kind of work you're in a hurry to get done. There is a reason Fender and Marshall used finger joints! Also, with my jig there are just enough teeth on the comb to do a 14" deep marshall cabinet. They're cheaper to buy on Craigslist (in general) but I wanted the option of building a historically correct 4x12.

I wouldn't say that's universally true but with this rig and solid pine or baltic birch ply I'm getting almost no tear out. I sometimes use a backing sheet or (for covered cabs) score the wood along the bottom of the cut with a razor blade to prevent the wood from splintering and tearing.

I have another table saw that (in time) will have the wings removed and it will have the dado blade and finger joint jig permanently affixed. I don't like having to fiddle with it all the time. I find that when it's set up and ready to go I'm more likely to try something and get it done.

Hope it's helpful to someone. I can take measurements and more detailed pictures if it'll help anyone out there.

Jamie

[cminor9]

Oh, is that jig on a table saw? It looked like a router table. Yeah, a dado will chew through anything! Some pics would always be cool. That's a very useful jig. Finger joints are more useful than dovetails IMO. If I wanted dovetails I'd get a Japanese hand saw and do em that way.