Simple woodworking question

[Kuro]

So I just got in the new Vifa tweeters for my line array, there is just one small problem. The old tweeters have a smaller hole, and there is no longer any material in the center for a hole saw to work (or circle jig).

Any idea how to get a larger hole while there is already an existing hole? I suppose I could use a jigsaw, but that would not be very clean, same with the router with the spiral bit.

Basically also the same issue with flush mounting the tweeter, since I always use a circle jig to start the outter diameter of the cut.

I'm sure someone here has some clever trick.

 

[Zing]

I have a suggestion that I'm certain will work well but I don't think you'll like it because it will require total disassembly. A drill press with one of those counter top circular sawtooth bit doohickeys.

:think:

 

[Kuro]

I have a suggestion that I'm certain will work well but I don't think you'll like it because it will require total disassembly. A drill press with one of those counter top circular sawtooth bit doohickeys.

:think:

That just might work, I could just remove the platform on my drill press. Would be a lot easier than ripping apart a box that's totally held together with wood glue.

Thanks for that idea, I will have to see if I can make this work!

 

[Zing]

I meant disassembly as in removing all the drivers, not deconstructing the box. I'm sorry I wasn't more clear. However I DID learn the less technical name for the doohickey I was referring to. It's a hole saw. But I bet you knew that.

 

[Botch]

A router and spiral cutter bit will work perfect, if you get one of those collar guides and make a simple jig. Let me see if I can find a link...

 

[Botch]

http://www.rockler.com/product.cfm?page=10671

You don't need to buy a whole set like this, you only need one of those collars that'll fit your router. You cut a pattern with a hole in the center, the hole will be the size you need to install your tweeters, plus twice the thickness of the collar "wall" over the whole diameter. The pattern will be the same depth as the depth of the collar wall, and then the cutting bit will extend thru the collar. All you'll have to do is clamp the pattern onto the speaker, centered over the existing hole, drop the router in and zip out the excess.

I'm not very good at explaining something like this, let me see if I can find a pic that makes more sense.

 

[Botch]

Well, this is even better:

This is a bit that has an integral ball bearing collar that rides against the pattern; this way the pattern hole can be the same size as the hole you need, kewl!
In the pic above, the ball bearing collar is the silver band on the router bit, and it is set at a height so it rides against the pattern (the black plate in the background drawing) and the cutterhead of the bit (blue in this drawing) then cuts the hole below.
Good luck!


EDIT: Sadly, that router bit probably costs almost as much as all your woofers combined... :?

 

[Rope]

How much material needs to be removed? MDF is relatively soft, so if it's a 1/2" or less, draw a circle around the existing hole, and use a wood rasp to cut away the excess material.

Rope

 

[PaulyT]

:eusa-whistle:

 

[Wardsweb]

The cleanest way would be to use a circle jig to cut the hole you want in some scrap wood. Clamp this as your pattern to the speaker face and use a flush trim router bit to cut the baffle.

 

[Yesfan70]

If the hole just needs to be a bit bigger, why not a spade bit or forstner bit?


The rasp will be the cheapest solution (unless you don't own one).

 

[Botch]

If the hole just needs to be a bit bigger, why not a spade bit...

If you ever try this, I wanna watch! :happy-smileygiantred:

 

[Yesfan70]

If the hole just needs to be a bit bigger, why not a spade bit...

If you ever try this, I wanna watch! :happy-smileygiantred:

I've done it more than once, with no issues.


Maybe I'm just lucky. :confusion-shrug:

 

[Kuro]

Thanks for the ideas on this.

I think that flush trim router bit should do the trick, then I can make a larger template, and raise the bit up to flush mount the tweeter.

As far as the hand tools... I need to make the hole about an inch bigger. This could take a while.

Even if the tools cost more than these speakers I don't have an issue with it, it will probably pay it's self off when I need to use it in the future. I think I spent more on tools than the speakers in the first place... $120 for a router, $30 in clamps, $30 in router bits and another 60 tooth blade $20. The next tool on the list is a plate joiner...

 

[lovemytoys]

what i used to do was take two hole saw 1 the size the hole is now 2 the size i need it to be. put the smaller one in side the bigger one.use ether a bolt or treaded rod with nuts and washer to holed them together.the small hole saw will work like an arbor .thats my 2 cents

 

[Botch]

what i used to do was take two hole saw 1 the size the hole is now 2 the size i need it to be. put the smaller one in side the bigger one.use ether a bolt or treaded rod with nuts and washer to holed them together.the small hole saw will work like an arbor .thats my 2 cents

:scared-eek:

:bow-blue: :bow-blue: :bow-blue:

:handgestures-thumbup: :eusa-clap:

 

[Kuro]

what i used to do was take two hole saw 1 the size the hole is now 2 the size i need it to be. put the smaller one in side the bigger one.use ether a bolt or treaded rod with nuts and washer to holed them together.the small hole saw will work like an arbor .thats my 2 cents

Wow, that's a brilliant Idea! I will keep that in mind the next time I do this.

 

[Kuro]

I finally got the new tweeters in, I just put a tick layer of masking tape over the general area and used a jig saw very carefully. This was probably the cleanest circle I have ever cut with one of those saws. I just got tired of waiting, and never had any time to pick up any router bits.

The new tweeters sound amazing compared to the $10 vifa's I had in there before. The DX25's are much more smooth and less "bright" than BC25's, as well as more detailed, this changed a lot about the speakers. Now I just need to get the right bit to flush mount them.

 

[malsackj]

Something not mentioned is to take another piece of wood and recut the hole use the center to mount to a small piece of ply underneath and mount to baffle. Then using the cutter to start the new hole and you will have a new size.

When mounting the hole piece and ply to baffle use the hole saw to help center in hole.
Just a thought for the next go around.