Why Use Finger Joints?

Seeing and hearing is believing

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WaZaK
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Post by WaZaK »

jaysg wrote:$50 for a head is about right.
Well, it's not exorbitant! The trouble is, that $50 is the base line: plus you have to make a front, plus make a back, plus do the roundover, plus fit cleats. That is quite a big "extra". Then it's got to be covered.
It is not exactly a bargain either IMHO - especially when compared with my $5 head!
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zeno
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Post by zeno »

I haven't visited here for quite some time, though I'm glad I did. With that being said, as I have been exhausting my own creative options for alternative cabinet refinishing. So with that now in mind, I say Thank you WaZak! Thank you for the great work you have shared & for inadvertently saving a total stranger an awful lot of time. An awful lot of time had I resorted to my own convoluted ideas. Brilliant work man!

Cheers!

p.s. From the looks of it my timing of paying a visit couldn't have been better :D
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WaZaK
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Post by WaZaK »

zeno wrote:Thank you WaZak!
You are more than welcome! That's what forums are for.....
zeno wrote:Thank you for inadvertently saving a total stranger an awful lot of time
There is no such thing as a stranger: only friends you have not yet met!
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Post by rickdog »

I use drawer lock router bits for both 1/2" and 3/4" on all my cabs. Fast and easy to use and very strong. For additional reinforcement I glue 3/4"X3/4" pine strips on all 4 interior corners. If it breaks, you're waaaaay to rough and anything else would almost certainly break as well.
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joebob
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Post by joebob »

I just finished this Head cabinet using biscuits and pocket holes. I used the Kreg jig to make the pocket holes and appropriate pocket holes screws for plywood. The Kreg jig is inexpensive and can be bought at Lowes. The Head cab is made with 3/4" plywood.
The combo cabinet has hand cut dovetails and made with 3/4 pine.

http://i255.photobucket.com/albums/hh13 ... IM0146.jpg
http://i255.photobucket.com/albums/hh13 ... IM0145.jpg

http://i255.photobucket.com/albums/hh13 ... IM1288.jpg
http://i255.photobucket.com/albums/hh13 ... IM1290.jpg

Dave
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rjgtr
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Post by rjgtr »

I tried box joins and just got too much chipout and adjusting the jip is a pain. I went to biscuits for all of my cabinets and haven't looked back. With modern glues the joint is very strong and I haven't had problem with a head or speaker cabinet yet.

Now if I was making a solid pine cabinet or something else finished with a stain and not tolex, I'd do box or dovetail joins, because they look better.
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Post by SkynyrdSurvivor »

I have had a lot of success with glued and screwed butt joints with a reinforcing block inside. They proved to be very road worthy as well.

Way back in 1973 I had 2 2x15 closed back cabinets that I set up for Ed King. He used 4 EV SRO 15s powered by an Ampeg V-4 head. This was his rig for almost 2 years until he suddenly left the band. After he left, we re-purposed the speakers and I gave the cabinets to Huey Thomasson of the Outlaws. I knew he liked Ed's sound.

Both of these cabinets were made of 3/4 inch plywood with butt joint corners that were glued and screwed and reinforced with a 1 1/2 square blocks across the inside of the corner, also glued and screwed. They were covered with a really tough Tolex style fabric reinforced vinyl I got from an automobile upholstery supply shop. I used Fender style chrome corners and black plastic grill cloth.

These cabinets were tough and took a lot of abuse on the road at the rate of almost 300 shows a year all across the country. They held up real good.

Late eighties, I reconnected with an old friend who still had two 2x15 bass cabinets that I had built for him in 1970 and they still were in perfect condition. Last that I saw those cabinets was in 1995 and they still looked great after 25 years.

Glued, screwed and reinforced butt joints hold up and should be an acceptable alternative for the builder that has limited tools, skills, money or time for the more elegant dovetails or finger joints.
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Wazak's awesome work...

Post by Hobbithacker »

Hey Wazak...was wondering if you could provide some dimensions for the wood used and the router bit used etc?

It looks awesome! And!!!! I have a huge amount of MDF available in my garage waiting for a real purpose in life!

Thanks!
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Post by StarGeezers »

Guys, when I make a cab , I always use front and back plates and rout a slot in the sides/top/bottom to accept the front plate (recessed) and rabbet the back(flush).. you can lay this out on one large piece of material (your choice) , do the routing in one go and then cut the pieces to final dimensions... Then I use butt joints/glue/screws (recessed)..sides long , top and bottom short. That way once the cab is glued up , the strength /stress is spread out over the whole cabinet, not just the edges... Very STRONG , and if the cab is to be Heavy Duty , then the blocks / fillets are added.. but be aware the best fillets are cut edge grain so the fiber of the wood is aligned perpendicular to the joined parts ... as a compromise, plywood may make better blocks ...and is easier
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Post by Cknopp »

Has anyone considered having a cabinet shot with the Rhino Lining bedliner stuff? I imagine that it would be SUPER durable, and if you did the inside and outside, you could actually make it out of foam blocks!
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Post by rjgtr »

Some people have used bed liner for a covering. I think the foam idea might be too resonant, but who knows.
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Badfinger
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Post by Badfinger »

the rhino covering and foam core would be about as dead as you could make a cabinet. Which would be great if that's what you were after.

Just personal opinion, but I still havn't heard anything I liked better for a cab than plain ol pine. I think it adds a warmth to the overall tone of an amp that hardwoods or plywoods don't have.

YMMV
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StarGeezers
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Post by StarGeezers »

I think what you guys are hearing with pine is resonance... We did some testing long ago with a spectrum analyzer and found natural woods resonate more than the other materials ... MDF was the least resonant , ply was in the middle ... All whatever you like huh !!!
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Badfinger
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Post by Badfinger »

Oh yeah, without a question, it is resonance added to the tone by the cabinet with pine.
Wouldn't want a cab without it.
:D
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CurtissRobin
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Post by CurtissRobin »

That's not resonance it's sympathetic vibration. The difference is big. An example of resonance is a cab with boomy bass.

First, materials:
Cut a scrap of pine, plywood and MDF of about the same size. Hold each by the corner and rap it with a drumstick, a screwdriver handle or your knuckle. The pine THOKs like a Wittner metronome and rings a bit with a distinct pitch. The ply THOKs as well but doesn't ring. The MDF is more leaden in sound, crisp but dull with no ring at all. Plywood and MDF damp the vibration quite effectively. You can use these characteristics to advantage. A pine cab will color the sound of your amp, chipping in its own vibrations complementary to the speakers. Ply colors a lot less than pine and a bit more than MDF, depending on its thickness. If you want only the sound of the speaker then 3/4" ply or MDF is the way to go.

Next, joinery:
If you build with pine, box ("finger") joints are best, though many other joints including rabbet or butt joints with cleats, glue and screws are excellent as well. With plywood or MDF the box and dovetail joints should be avoided because at least 40% of the grain runs the wrong way. i.e. At least two of five plies (or five of eleven if you use baltic birch) are not end grain so the stress on a box or dovetail joint is working to split the wood in those plies. No strength there.

Finally, cost:
MDF is the lowest cost material, hands down. Plywood (of a good grade) is most expensive with #2 pine somewhere between. When I read posts about the cost of a cabinet I think about living in L.A. some years ago. On the street you'd see an astonishing multi-thousand dollar paint job that was applied on top of $300-$400 of body work. Do what's important to you.

KennyO
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Post by StarGeezers »

CR, makes good sense to me !!! Thanks !!! I stand corrected on the resonance thing , all the cabs we tested resonated on the lower freqs.
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Post by Badfinger »

Sure, I agree on all points as well CR.

I still like Pine cabs.

:D
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Cknopp
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Post by Cknopp »

Badfinger wrote:the rhino covering and foam core would be about as dead as you could make a cabinet. Which would be great if that's what you were after.

Just personal opinion, but I still havn't heard anything I liked better for a cab than plain ol pine. I think it adds a warmth to the overall tone of an amp that hardwoods or plywoods don't have.

YMMV
Is this statement based in fact, or is it just a gut feeling?

I would really like to see evidence that leads you to that conclusion, because I have yet to find any of the sort in my time researching the idea (about 2 years).

Thanks!

Chris
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Post by Badfinger »

First, I'm not saying it would be a bad thing. Quite the opposite, depending.

I built cabinets pretty steadily for a time through the mid-nineties, mostly FOH and monitor cabinets, but some guitar and bass cabs as well.

One method I played with was 3/4 birch ply front baffles, 1/4 ply inner box, with industrial urethane-based foam around 1 inch thickness, and an early version of bedliner sprayed over that. There were some braces along the edges and bottom of 1.5 by.750 ply also.
I found those enclosures to be very "dry", at least in comparison to similar cabs built more traditionally, with ply mainly.
It was a bonus for sound-reinforcement speakers.
I didn't care for it with guitar/bass cabs, other did. In fairness, I did'nt make many guitar cabs with the method so I couldn't say they were as "dry" in that instance as I found them otherwise.

I think it might depend on the foam to a large degree. My first attempts were with styro and insulation foam board, and I didn't like those at all, personally. A lot of ringing in the upper mids in particular.

Anyway, that's what i found, YMMV.

Still think pine sounds way cool for guitar cabs.

:D
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