RACO shielding technique

[zpyder]

Hey guys.

I put together my first build last weekend  ... a Green Ringer with the tonepad PCB.  Everything went smoothly and the little guy fit perfectly into one of the smaller RACO boxes with a couple standoffs.  It sounds great, I'm really happy with my first.    I'll post some pictures when I transfer them to my computer.

I have a couple of questions though...

First, I used switchcraft jacks and they are grounded through their nut to the chassis.  The LED and circuit are grounded directly to the - lug on the 9v jack (no battery in this one).  The 9v jack, though, is plastic and needed to be grounded.  So I attached a lead and stripped off a good 1" or so, put it behind the washer that holds on the 9v jacks, and tightened it down.  I even put a dob of solder there, but I think it didn't weld well to the aluminum(?) box and might be pointless.  Should be A OK, right?  I've got some plastic marshall jacks too, that I would have to ground.  On these I would want to ground them directly to the -9v lug in order to avoid a ground loop, correct?

Second, is that thing shielded??  I mean, it's a metal box (with some small holes) that's grounded through the chassis... would I need to apply any foil at anything to shield it or is that accomplished by grounding the chassis?  BTW I painted the outside with regular spraypaint, not that I think it makes a difference...


THANKS!!!
zpyder

[comfortably_numb]

The box itself acts as a shield

[rockhorst]

Plastic is an insulator, grounding it is pointless. Ground the metal pins.

[zpyder]

rockhorst-

jesus man, I may be a newbie but I still have enough sense not to try to ground plastic...!  Of course I was grounding the lugs... 

Here's a new question-
What do you guys use to drill into your RACO boxes?  I've been using the pre-existing holes in the "back" and some large washers, but I've seen several build pics out there that where people have drilled through the "front" (cap/lid) and they looked pretty nice.  Anybody who's done this want to tell me about their sweet bit/piece of shit bit ?

thanks,
zpyder

[petemoore]

  Metal jacks in metal mounting holes with nuts clamping them...connect, in my tests with DMM.
 DC jacks of variety present a variety of ways they can be wired, I use metal non switch type, wiring pin +, the barrel is -ground, and tests as 'connected to' by DMM, when tightened into a metal hole.
 I think it's GGG site that shows PS wirings, it is easier to describe circuit wirings by schematic, and this also aids discussion.
 

[petemoore]

  I use bits, Varibit is the best solution to drillings for Stompboxes...as long as you don't go one ring too many when drilling different sized holes.
  Epoxying the RACO punchouts, so they are more rigid, helps prevent punching them out while drilling, quickset JB weld and other epoxies performed this task for me, with no more than medium drill pressure.
  I drill from the top very squarely just until the shoulder/side of the bit gets under the top surface, then I drill from the bottom to finish the hole, this prevents larger burrs upon bit exit, and makes finishing the shoulders of the
holes easier, using a larger bit to take the remaining burrs off quickly by slightly 'champhoring' the edgesof the holes.
 
 

[zpyder]

petemoore-

nice idea about flipping the lid over for secondary drilling...  Excuse for asking, but I've only really drilled wood... do I need a special drill bit?  A metal drill bit I would assume...

thanks for all your help,
zpyder

[petemoore]

  If your intending to do some' drilling, the 'better' bits, or at least metal cutting bits are what you want to use.
  I find a small but 'sturdy' bit works as well as a punch, if I'm real square, at getting an accurate start notch going, using a punch could punch out the punchout.
  Once I get hole[s started [I mark all the holes and start 'em before changing bits], I bump up to around or 1/4'', good for mini-switches, then pot size bit to do the potholes and jackhole size *bump,  [it makes it easy to drill so much at a time, instead of starting with a 1/2'', I'll *bump it up as I go], moving to the next larger bit as needed for the holes.
  After typing all that...you can see why a varibit and paying close attention to the hole sizes...you might do well to have different type or colored marks for the different sized holes, you're half likely to make one varibit mistake, developing a method might help prevent this...keeping whatever it is your'e drilling the hole handy and checking the size after a varibit ring has done it's cutting, before moving up to the next diametere....

[rockhorst]

jesus man, I may be a newbie but I still have enough sense not to try to ground plastic...!

Wasn't trying to insult you there. Sometimes you just don't know
Re-reading your post I understand that you want the jack to make direct contact with the enclosure. I don't think that's really necessary, just connect the minus lug of the dc jack to the ground. But I guess you already figured that out.

[zpyder]

rockhorst-

no worries ...  I thought it was pretty funny though.   
I'm picturing a guy with a soldering iron up to a plastic casing ... melting and smoking and bubbling ... and getting all aggrivated - "WHY WON'T IT WELD!?"

hehehe
zpyder