Jager Screws

[Josh.G]

Hello, I wanted to let you all know, when I opened the package of screws to mount the impedance compensation boards I noticed they were 1" screws and not 3/4" as they should be.  I suggest checking the length of your screws, if you mount anything to 3/4" plywood with 1" screws you will poke holes through the wood.  Cheers, everything else is going very smoothly.
-Josh

[Doc B.]

You did use the standoffs to mount the board, I hope. With the nylon standoffs 1" screws will not go all the way through, as the standoffs are 1/4" and the impedance board is 1/8". That leaves 5/8" to penetrate the 3/4" (actually 19mm) birch ply.

[Josh.G]

It isn’t the board I was concerned with but the drivers, but as Josh mentioned to me those have pilot holes already, thanks for your help.

[Doc B.]

Not sure I understand how having pilot holes relates to the length of the screws. The drivers sit in a rabbet so the front of the woofer floating on the o-ring is flush with the front panel.  The panel is probably something more like 1/2" thick where the driver screws go in. At any rate, it doesn't make a difference in the look or performance, and a longer vs shorter screw length assures the best possible clamping of the part to the panel. The main thing is to make sure that the driver is snug on the o-ring for an air tight seal, but not so torqued that the o-ring is crushed. The idea is that the driver be isolated from the box by the flexible rubber on either side of its flange.

[bombay317]

I know that when I was going through that part of the build I recalled the instructions saying 3/4" screw, but the bag is full of 1" ones.  It is the third step on page 21.  First I was confused, but when I looked at the stack-up and the fact that the quantity of screws was right, I just used the 1" ones.  There was no protrusion out of the bottom.

[Doc B.]

Yes, either length works fine.

[Josh.G]

I was thinking that the 1" screws would penetrate through the plywood when mounting the drivers, compromising an airtight seal of the speaker.  Since there are pilot holes drilled all the way through there anyway, it the same difference with any screw length as long as the screw seals up everything completely.  Thanks for addressing my unfounded concerns, I appreciate it!

[Paul Birkeland]

I was thinking that the 1" screws would penetrate through the plywood when mounting the drivers, compromising an airtight seal of the speaker.

The ports will compromise the airtight seal of the speaker.

[Doc B.]

It's a little more complicated. Yes the ports are holes that air can flow out of. But other leaks in the cabinet will compromise the function of the tuned ports and take away from the bass dynamics.

But the point is that running a 1" screw into a piece of 3/4" plywood does not make a leak of any consequence. Pull the screws back out and yeah, you would have leaky holes. And your driver would fall out.