standoff problem

[aragorn723]

Hi,

I built a circuit board for the 3d imaging preamp listed on the board here a while ago, and have a potential issue for mounting it into a chassis.  The board is perf board, and two of the traces come very close to the mounting holes (they are both signal paths).  The board will go into my old Quickie chassis, which now has a 6 X 10 aluminum plate on top.  Originally, I wanted to mount the board to the plate (underneath) and also the RCAs, but since these 2 traces are so close to the mounting holes, they will probably touch the standoff, and potentially short to ground.  I might be able to bend them a little bit and use an insulated standoff, but was wondering what other options there are (maybe somehow mounting the board to the inside of the wood for the chassis?  Any ideas?  Thanks,

Dave

 

[Paul Birkeland]

Use a nylon standoff and a plastic screw.

 

[aragorn723]

A 4-40 nylon screw looks like it might work ( gotta pull out a metal one to check), but the nylon but is 1/4" ( from home depot).  This is probably going to be a game of millimeters to see if it fits!  Gonna give that a try, but if not, that might mean desoldering the resistor in qustion, and relocating to another spot on the board.  Will let you know how it goes!

Thanks, Dave

 

[mcandmar]

Probably not much use to you now due to shipping times, but you can buy kits of nylon standoffs from eBay for very little, worth keeping a few in stock.

http://www.ebay.com/itm/131610830796

 

[aragorn723]

That's good to know!  I still have to set up my drill press and get a bunch of holes drilled (first time ever).  Gonna check out evay tonight!

Dave

 

[aragorn723]

What is the metric equivalent of a 4-40 screw?

Thanks,

Dave

 

[Paul Birkeland]

What is the metric equivalent of a 4-40 screw?

This is a question that has no answer.

A 4-40 screw has a shank diameter and thread pitch that do not match any metric screws. 

 

[mcandmar]

The closest in size visually is an M3 x 0.5mm thread, but as above they wont screw into each other.

 

[rif]

Amazon has standoff kits some with one day delivery.