Tight or too small openings?

[greenie512]

One of my greatest fears as a speaker builder is building a cabinet only to realise I’ve cut the speaker openings to small. Which usually leads me to doing at least a few dummy cut outs before I tackle this job? However I’ve often pondered on a quick and clean way to “open” up a circle if necessary.

Recently I did a swap with a mate for a pair of my cabinets, I wanted to use the drivers in something else and he was happy to source his own speakers, however on arrival they apparently don’t fit my (admittedly tight) openings even though they are the same speaker!

Here’s my solution: -

1. Add the bottom roller guide to my laminate trimmer but the roller is set 1mm or suitable back from cutting edge of bit
2. Bit set to cut half thickness of board, roller rider lower part of board
3. Cut around opening and basically get a micro rebate
4. Remove lower guide.
5. Drop bit lower so the top roller guide now rides the new rebate
6. Cut around opening again to remove bottom “lip”

Vola, perfectly extended and flush circular opening

Gawd .. it's raining in Brisbane ... beautie

[BobL]

I would have thought cutting the opening too large would be even worse than too small?:D

Otherwise a nice solution.

[soundman]

Thats not a bad option.

better not to make your holes too tight.:doh:

A couple of mm clearance never did anybody any harm.

I can remember in the arly days, getting stuck into the odd speaker hole with a big rasp.:B

one other option would be to fix a cleat on the back of the bafflle & rig a center point off that.

I've had to open up quite a few horn tweeter holes and bung a few up too.

But these are usualy uggly rock & roll boxes:~

cheers