Keeping the cabinet square

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rogerc
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Keeping the cabinet square

#1 Post by rogerc »

I've just started building 2 Jacks but I can't see that the method suggested in the plans (fitting top and bottom of the cab to the horn/baffle and then fitting the sides) can result in a square cornered cab. If the horn dimensions or angles are marginally off, the error is magnified at the cab edges. I part assembled mine and found this problem so I've taken them apart and will be constructing the cab carcase first and bracing this square, and then fit the horn/baffle assembly to the carcase. This way I can shoot the horn assembly to fit.

Anyone else found this an issue?
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JerryTyzack
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Re: Keeping the cabinet square

#2 Post by JerryTyzack »

I used the techniques Bill describes in the plans with no problems. I am an inexpert woodworker. One box came out perfectly square, the other was fractionally out (about 2-3mm). The only precaution I took was I waited until the box was finished before trimming the back to fit. As I lack woodworking experience and was using fairly basic tools (I don't have access to a table saw) I found the method Bill describes allowed me to correct for minor errors as I went along. The main thing is take it steady and make sure your joints are airtight. Have fun!!
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bzb
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Re: Keeping the cabinet square

#3 Post by bzb »

My OTs are slightly off square due to me rushing it. One thing you can do is build those clamping jigs that are in some of the Titan threads - I think Bruce Weldy did them.

I just used a small framing square and snapped in some brads to hold them in place. If it's off square, you just take a heavy rubber mallet and bang the box until the diagonals are equal. Obviously the more bracing that's in there, the less they're going to move. Best to do this after the PL has set up a bit but not fully cured. Even after that, I'd still run a small bead along the inside of the joint to be sure.
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Harley
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Re: Keeping the cabinet square

#4 Post by Harley »

Bill's method works fine for me but I have two things, the first being essential.

First is to make sure your table saw is cutting 100% accurate square and that you feed the ply in properly. I take hours setting up my saw regularly and it pays dividends.

This alone will help you overcome the problems you described.

Secondly, because I make a few of these things, I have a jig made up to hold the throat/baffle assy square to the top. I won't post a pic because this is my IP sorry, but it's not rocket science to make one up. You should only do that though if you plan on making 8 or more in one hit.

Look after your table saw, cut dead square and you're home and hosed :mrgreen:
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Rickisan
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Re: Keeping the cabinet square

#5 Post by Rickisan »

I followed the plans and got a good result. All dimensions within 1/16". This was my fourth cabinet after starting the first with only middling woodworking experience. The 2nd 3rd and 4th came out much better than the first! It would be harder to me to fit the innards after the box was built but I guess it could work.

Keep at it... it will get better.... and Good Luck! :clap:
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SoundInMotionDJ
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Re: Keeping the cabinet square

#6 Post by SoundInMotionDJ »

"Perfectly square" and "wood" do not get along. "Almost perfectly square" is a much better and achievable goal.

Woodworking tolerances vary considerably...in framing 1/4" is more than close enough. Finish carpentry can be 1/16" off...that's what caulk is for. Cabinet and furniture making has tolerances a lot more like metal working...in thousandths.

Your fingers are a better for getting two pieces of wood "the same" than any ruler will ever be.
Harley wrote:First is to make sure your table saw is cutting 100% accurate square and that you feed the ply in properly. I take hours setting up my saw regularly and it pays dividends.
+1 000 000

Build a table saw sled first. Spend hours getting it better than you think it needs to be. It will pay for itself over and over and over again.
Harley wrote:Secondly, because I make a few of these things, I have a jig made up to hold the throat/baffle assy square to the top. I won't post a pic because this is my IP sorry, but it's not rocket science to make one up. You should only do that though if you plan on making 8 or more in one hit.
Jigs and templates are your friend. Even building just two cabinets, making the jigs is a good investment. Not for saving time...but for requiring you to think through the process and steps. With four cabinets, you will start to save time.

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Greg Plouvier
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Re: Keeping the cabinet square

#7 Post by Greg Plouvier »

Make sure you're measuring and cutting off of a square corner on your sheet so all your pieces come out square. Ply particularly baltic can be not square. If the rear is a little out of square at the end throw a clamp across the longest diagonal and pull it into square. Check the sides with a framing square and check that diagonal measurements are = . Tack a brace on diagonally until the glue cures.
SoundInMotionDJ wrote:Woodworking tolerances vary considerably...in framing 1/4" is more than close enough. Finish carpentry can be 1/16" off...that's what caulk is for
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Bill Fitzmaurice
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Re: Keeping the cabinet square

#8 Post by Bill Fitzmaurice »

Greg Plouvier wrote: Not in my world
Of course not, as you're a pro. Amateurs can't and shouldn't expect that level of precision. The good news is that level of precision isn't required, even with 1/4" tolerance they might look a bit off, but they won't sound a bit off.

spongebob1981
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Re: Keeping the cabinet square

#9 Post by spongebob1981 »

As of my experience, I know exactly what you mean.
I dont think I got any 2 panels square to a third :slap:
Nevertheless, as almost everything in my life lol, bondoed the whole thing, added a little duck tape... and they sound like they should I guess.

And you can't tell by looking at them 5 feet away :cowboy:
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rogerc
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Re: Keeping the cabinet square

#10 Post by rogerc »

Thanks for your replies. I have built my outer boxes square and used the baffle to hold them that way. I will be fitting the horn and duct components to the assembled box. This seems to me to be easier than trying to fix the top to the baffle and at the same time aligning it with the base edge and sides etc.

I don't have a table saw so all my cutting is by hand (planed to fit). So far it's all dead square :D
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IanChad
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Re: Keeping the cabinet square

#11 Post by IanChad »

I'm glad that someone has 'fessed up to this. My Jacks are slightly out but I thought that I was the only one. Now I find that there's others who have had the same problem I don't feel too bad about it. The worse of my two J110s was only about 1/8 inch out but it was enough to make it wobble on a perfectly flat surface. good news is that, once the rubber feet were on, the problem seemed to go away and they don't look crooked.
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SoundInMotionDJ
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Re: Keeping the cabinet square

#12 Post by SoundInMotionDJ »

I have a T39 that is twisted 1/4" out of square from corner to corner. A combination of shaving the high corners, and padding the low corners has gotten it "flat enough" to not wobble when it is in a stack.
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rogerc
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Re: Keeping the cabinet square

#13 Post by rogerc »

I was finding it really difficult to line up the top on the baffle/horn and keep the back/front and side edges aligned and square. The downside of building the shell first is that it's more fiddly to get the baffle/horn assembly positioned and glued up but it seems a more logical build sequence.
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gdougherty
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Re: Keeping the cabinet square

#14 Post by gdougherty »

rogerc wrote:I was finding it really difficult to line up the top on the baffle/horn and keep the back/front and side edges aligned and square. The downside of building the shell first is that it's more fiddly to get the baffle/horn assembly positioned and glued up but it seems a more logical build sequence.
Might seem like it, but it's not the better way to do it IMO. It's easier to twist the shell pieces during assssembly to fit the marginally out of square internals than it is to twist the pre-assembled, well braced internals to a square exterior. Besides, the net result would probably be the same unless you had something assembled to the box that forced the outer shell to remain in square.

bgavin
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Re: Keeping the cabinet square

#15 Post by bgavin »

SoundInMotionDJ wrote:I have a T39 that is twisted 1/4" out of square from corner to corner. A combination of shaving the high corners, and padding the low corners has gotten it "flat enough" to not wobble when it is in a stack.
Two rear wheels and a front-center pad cures this one.
My T39 has the same symptom, and the triangular footing is a quick fix.

The alternative is shimming the offending front left or right foot.
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