What Size Router Bit for 1/2" Plywood Cab

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AxeMan7
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What Size Router Bit for 1/2" Plywood Cab

#1 Post by AxeMan7 »

It seems that the 1/2" radius router rounding bit would cut too much off the edge to provide for nailing without splitting on 1/2" plywood cabinet sides, top and bottom.

I realize after curing that the glue is doing all the holding, but nailing to hold it together seems difficult with such a rounded edge.

Should I go to a 1/4" radius bit and then just use square corner protectors instead of the standard radiused ones?

I would like the cab to match my amp head corners which are rounded though. The amp head enclosure is 3/4" which makes those corners fit with a 1/2" edge radius.

Any suggestions?

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Seth
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Re: What Size Router Bit for 1/2" Plywood Cab

#2 Post by Seth »

Edges are usually flush trimmed and rounded after the cab is assembled. So, it's not so much about difficulty nailing on a rounded edge, as it is difficult to round an edge that's full of nails/brads/staples/pins.

An option is to use screws, so they're easier to remove prior to flushing and rounding. It's a little more work to predrill screwholes, drive screws, then remove them all. But, I think it's the more popular option.

Not the "right" thing to do, but the last couple I did, I used 18 gauge brads for assembly and just decided to sacrifice a roundover bit and just cut through any brad heads that were in the way. The bit was still usable when I finished, although noticeably dulled.

Could also do 1/4" roundover and custom file/sand to fit the corners.

I'm sure there's a few more solutions that would work well for you too. Please keep us posted as it comes together. No matter which direction you choose, it's always interesting to read about. :thumbsup:
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Bruce Weldy
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Re: What Size Router Bit for 1/2" Plywood Cab

#3 Post by Bruce Weldy »

I've used a 3/8" roundover on all of my cabs. If you use a brad nailer and keep it toward the inside of the cab when you shoot, it's not a problem. My bit has eaten through those brads without even leaving a nick.

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jimbo7
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Re: What Size Router Bit for 1/2" Plywood Cab

#4 Post by jimbo7 »

Bruce Weldy wrote: Thu Apr 07, 2022 3:28 pm I've used a 3/8" roundover on all of my cabs. If you use a brad nailer and keep it toward the inside of the cab when you shoot, it's not a problem. My bit has eaten through those brads without even leaving a nick.
+1
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Bill Fitzmaurice
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Re: What Size Router Bit for 1/2" Plywood Cab

#5 Post by Bill Fitzmaurice »

+2. The standard radius for corners is 3/8", and you do the routing after the cab is assembled.

AxeMan7
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Re: What Size Router Bit for 1/2" Plywood Cab

#6 Post by AxeMan7 »

I will need to get a smaller router if I do it after assembly.
My two routers are 3hp. One is in a custom router table and the other is just too large for the job.

I used to have a 1 1/2 hp Craftsman. Maybe it’s on a shelf somewhere in my shop.

I’d be more apt to use screws (even with ore-drilling) if I was using 3/4” or 1” solid wood than 1/2” Baltic Birch plywood.

Thanks for the tips.

ACUA
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Re: What Size Router Bit for 1/2" Plywood Cab

#7 Post by ACUA »

Bruce Weldy wrote: Thu Apr 07, 2022 3:28 pm I've used a 3/8" roundover on all of my cabs. If you use a brad nailer and keep it toward the inside of the cab when you shoot, it's not a problem. My bit has eaten through those brads without even leaving a nick.
+3
Last edited by ACUA on Sat Apr 09, 2022 10:14 am, edited 1 time in total.
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Bill Fitzmaurice
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Re: What Size Router Bit for 1/2" Plywood Cab

#8 Post by Bill Fitzmaurice »

If you were to use screws then you'd have to use a lot of countersinking or remove them before routing. I'd guess that routing before assembly will double the build time.

AxeMan7
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Re: What Size Router Bit for 1/2" Plywood Cab

#9 Post by AxeMan7 »

I think I will order a few more Pony Clamps for the corners and strap the middle. That way I wont need any nails at all. I do have a 18 ga pneumatic brad nailer that I can shoot some 3/4" nails in if needed. The safety is removed so it do some very close work.

My first speaker cab build, but I've built pretty much everything from boats to houses before. Hopefully the Tolex will come out looking good. :D

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Re: What Size Router Bit for 1/2" Plywood Cab

#10 Post by Bruce Weldy »

AxeMan7 wrote: Fri Apr 08, 2022 7:33 am I think I will order a few more Pony Clamps for the corners and strap the middle. That way I wont need any nails at all. I do have a 18 ga pneumatic brad nailer that I can shoot some 3/4" nails in if needed. The safety is removed so it do some very close work.

My first speaker cab build, but I've built pretty much everything from boats to houses before. Hopefully the Tolex will come out looking good. :D
You need the brad nails to keep the panels aligned. PL is slippery. Trying to just clamp it together would probably be the most frustrating thing you've ever done.

6 - T39 3012LF
4 - OT12 2512
1 - T24
1 - SLA Pro
2 - XF210


"A system with a few knobs set up by someone who knows what they are doing is always better than one with a lot of knobs set up by someone who doesn't."

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Bill Fitzmaurice
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Re: What Size Router Bit for 1/2" Plywood Cab

#11 Post by Bill Fitzmaurice »

Or you could just follow the plans. :horse: :cop: :bash: :wall:

AxeMan7
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Re: What Size Router Bit for 1/2" Plywood Cab

#12 Post by AxeMan7 »

Bill.
I see patience it not one of your virtues!

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Bryan Cox
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Re: What Size Router Bit for 1/2" Plywood Cab

#13 Post by Bryan Cox »

18 ga brads work beautifully. I find that I can make great progress on a weekend when I use them. The only time I worry about clamps is if something is warped or to momentarily align a joint. But, to each their own.
Otop 12 x 4 (Delta Pro 12-450a) 2x melded, 2x straight
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Bruce Weldy
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Re: What Size Router Bit for 1/2" Plywood Cab

#14 Post by Bruce Weldy »

Bryan Cox wrote: Fri Apr 08, 2022 6:18 pm 18 ga brads work beautifully. I find that I can make great progress on a weekend when I use them. The only time I worry about clamps is if something is warped or to momentarily align a joint. But, to each their own.
Absolutely!

I built my first T39s with the cabinet screws, then took 'em out after the PL dried plugged the holes. After that, it's been all brad nails with the few exceptions where it's hard to line up an interior panel and shoot it from below - then I'll put a screw in each end of the panel to get it locked into position, then brad nails in between.....but that's usually only on big cabs like subs where you have to attach it from underneath.

6 - T39 3012LF
4 - OT12 2512
1 - T24
1 - SLA Pro
2 - XF210


"A system with a few knobs set up by someone who knows what they are doing is always better than one with a lot of knobs set up by someone who doesn't."

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Bryan Cox
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Re: What Size Router Bit for 1/2" Plywood Cab

#15 Post by Bryan Cox »

Bruce Weldy wrote: Sat Apr 09, 2022 7:49 am
Absolutely!

I built my first T39s with the cabinet screws, then took 'em out after the PL dried plugged the holes. After that, it's been all brad nails with the few exceptions where it's hard to line up an interior panel and shoot it from below - then I'll put a screw in each end of the panel to get it locked into position, then brad nails in between.....but that's usually only on big cabs like subs where you have to attach it from underneath.
I did the same. I built my first Otop 12 exclusively with screws and I found that I didn't gain much more than extra steps at the end. Like you, I now only use screws if it's necessary.
Otop 12 x 4 (Delta Pro 12-450a) 2x melded, 2x straight
Titan 39 x 4 (3012LF) 20" wide

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