Quick router question re widening a woofer flange cutout.

[jhollander]

Re: Quick router question re widening a woofer flange cutout.

With non-round drivers you learn to make a lot of driver templates. Some guy with a CNC could probably sell a few templates for routers with bushings.

I would have bought a SEOS12 template. Erich you can use this idea...

[Paul Carmody]

Re: Quick router question re widening a woofer flange cutout.

Just go with a rabbet bit. If you can't find the right bearing, get the next smallest size and wrap some tape around the bearing to get the right size.

You're assuming the inside of my woofer cutouts are perfectly round, which they rarely are (because I'm sloppy when the cut is finished) :p

[CWH&R]

Re: Quick router question re widening a woofer flange cutout.

Dang why didn't I think of that--so fixated on using the existing hole for my guide, couldn't see such an elegant solution as to route from the outside!. And yes I bet I can eyeball (as we all could) within a few thousandths given how little the hole needs to be enlarged.

And I am really glad to have asked the question; almost didn't because it seemed so well--trivial, but I find it's these little lessons in how many ways a cat can be skinned that prove so very helpful in stretching my limited skill set.
I'll decide once parts are in hand--both woofers and cabs are on their merry way!

Thanks again and Happy holidays to all.
JRS

I have the same ordeal going on with 1 of my dynamic 4T , 4 holes in the bottom. Been thinking about it for weeks now but this post just gave me some good ideas.

[fastbike1]

Re: Quick router question re widening a woofer flange cutout.

Just go with a rabbet bit. If you can't find the right bearing, get the next smallest size and wrap some tape around the bearing to get the right size.

[JRS]

Re: Quick router question re widening a woofer flange cutout.

One more option...

Create a template by cutting a hole equal to the size of the O.D. of the driver, in a piece of 1/4" scrap plywood or hardboard.

Now align (center) the template over the existing baffle hole, and secure with double-sided carpet table.

Finally, use a pattern bit with top-mounted bearing in your router to trim the existing rebate to the template.

Dang why didn't I think of that--so fixated on using the existing hole for my guide, couldn't see such an elegant solution as to route from the outside!. And yes I bet I can eyeball (as we all could) within a few thousandths given how little the hole needs to be enlarged.

And I am really glad to have asked the question; almost didn't because it seemed so well--trivial, but I find it's these little lessons in how many ways a cat can be skinned that prove so very helpful in stretching my limited skill set.
I'll decide once parts are in hand--both woofers and cabs are on their merry way!

Thanks again and Happy holidays to all.
JRS

[badman]

Re: Quick router question re widening a woofer flange cutout.

Quick and dirty- A drum sander attachment for the drill is very handy- it's also useful for shaping cutouts for good airflow, and other applications. You may have to clean out the "corner" with a knife or chisel or screwdriver tip because it's difficult to get the sander flush with the bottom surface, but that's easy to do. It's actually pretty easy to be reasonably precise and controlled, if you go slow. The article has a pic:

http://www.enjoythemusic.com/diy/0710/creative_sound_trio.htm

[Squidspeak]

Re: Quick router question re widening a woofer flange cutout.

The beauty of my template method (above) is that you don't have to waste any time finding the center or worrying how close you are. Placing the template concentrically with the existing hole is quite easily done by eyeball (though you can measure if you like).

It probably takes me about the same amount of time to make a template as it would take to build-up a new center. But if I have more than one cabinet to do, the subsequent cabinets go much faster.

Try the template.

I always go the template route, I like to do a test hole from the template before I rout the baffle. Once you know your template
is good you can make multiple copies that are consistent. I usually make the template to cut the hole then use a rabbiting bit to cut the flange. The OP can
just make the template for the flange size instead.

[philthien]

Re: Quick router question re widening a woofer flange cutout.

The beauty of my template method (above) is that you don't have to waste any time finding the center or worrying how close you are. Placing the template concentrically with the existing hole is quite easily done by eyeball (though you can measure if you like).

It probably takes me about the same amount of time to make a template as it would take to build-up a new center. But if I have more than one cabinet to do, the subsequent cabinets go much faster.

Try the template.

[skatz]

Re: Quick router question re widening a woofer flange cutout.

I've done this a number of times as well, and never had much trouble. What i did was use the original cutout portion of wood, putting it back into the hole it was cut from, and fixing everything in position with double sided tape. It actually holds adequately to position the pin from the circle jig, whichever type you use. You can position it pretty accurately by eyesight, since the cutout size doesn't differ from the baffle hole very much, and you simply look for a symmetrical gap all the way around.
I did purchase a 3/4" rabbet bit (1/2" shank) just recently from MLCS, and if that is too big you can see about other bearing sizes to reduce it. I am not sure what .64" translates into, its a hair larger than 5/8's.

[richard t]

Re: Quick router question re widening a woofer flange cutout.

If you make an 1/8 inch rabbet deep enough to the size you need and switch to a trim bearing bit to enlarge what was left by the rabbetting bit, trimming it flush. Should work well with little effort. !/16 of an inch would be tough rabbet bit size to find if it's 1/8 larger in diameter but if you have to go a little larger, it shouldn't matter too much if your flange is large enough.

[mattsk8]

Re: Quick router question re widening a woofer flange cutout.

I've done this so many times I can probably do it blindfolded. It works well, but still is time consuming. Hot melt glue works well to hold the backer piece in place, and a few taps with the hammer knocks it out when you're done. The toughest part is finding the exact center of a hole--there are tricks, though. If you already have screw holes, then drawing lines across will pinpoint the center. Otherwise, you'll be drawing some tangents and finding their centers (sort of like this figure).

Use the 2" mark on your tape for the starter when you measure edge to edge across the recess. I've never really had a problem this way.

Here's what I started with...


Wood glued in the center...


New hole cut in...


And the end result. This one I had to recess the tweeter enough that the woofers would lay over the tweeter's face a tiny bit, otherwise I'd need to redo that entire baffle...

[Paul Carmody]

Re: Quick router question re widening a woofer flange cutout.

3. Glue a piece of wood to the back side of the cutout you have now, then glue another to that piece that sits inside the cutout you currently have. Now you can use a Jasper Jig (assuming you have one?) to cut your recess the size you need it to be.

Option 3 will yield the best results, but this is assuming you have a Jasper circle cutting jig.

I've done this so many times I can probably do it blindfolded. It works well, but still is time consuming. Hot melt glue works well to hold the backer piece in place, and a few taps with the hammer knocks it out when you're done. The toughest part is finding the exact center of a hole--there are tricks, though. If you already have screw holes, then drawing lines across will pinpoint the center. Otherwise, you'll be drawing some tangents and finding their centers (sort of like this figure).

[mattsk8]

Re: Quick router question re widening a woofer flange cutout.

Screw, not glue, as these will be temporary. OP, what you're doing is to in effect return the baffle to an 'uncut' state so that you can use a Jasper to re-cut the recess.

No, glue not screw... just don't get carried away with the glue. Once I'm done I take a wood chisel and knock the temporary piece out. I'm not a fan of using screws (especially in the tweeter area because it's already small) because you're making another hole that doesn't need to be there, plus it's not as stable as it would be with just glue. This was one I did where I swapped the original tweeter with one that was quite a bit bigger diameter. The red rectangle would be the board I glued to the backside.

[philthien]

Re: Quick router question re widening a woofer flange cutout.

One more option...

Create a template by cutting a hole equal to the size of the O.D. of the driver, in a piece of 1/4" scrap plywood or hardboard.

Now align (center) the template over the existing baffle hole, and secure with double-sided carpet table.

Finally, use a pattern bit with top-mounted bearing in your router to trim the existing rebate to the template.

[billfitzmaurice]

Re: Quick router question re widening a woofer flange cutout.

Glue a piece of wood to the back side of the cutout you have now, then glue another to that piece that sits inside the cutout you currently have. Now you can use a Jasper Jig (assuming you have one?) to cut your recess the size you need it to be.

Screw, not glue, as these will be temporary. OP, what you're doing is to in effect return the baffle to an 'uncut' state so that you can use a Jasper to re-cut the recess.

That may be the advantage of trying to cut a dummy disc exactly the size of the cutout as that will be certainly centered.

It's not worth the effort. You just have to make sure that the jig pin placement hole is centered in the driver cutout.