Chassis tolerance ?

[pula58]

I am trying to put-together a design for a chassis. Let's say I have an AC power jack whose dimensions are 15/16" by 1 1/4". Should the chassis opening be exactly that size, or, slightly larger. If larger, in your experience how much larger?


Also, I saw a post here where someone mentioned a chassis prototyping service where you sen them the files and they crank out the chassis.

What thickness aluminum are you all using?


Thanks!

P.

[selloutrr]

exact if you are not powder coating.
1/32" to allow for powder coating.

Again this will depend on the manufactures spec sheet and cad drawings. often times they will spec the hole size required for installation.

12Guage is commonly used for chassis.

[Gaz]

Every part on an amp has a little wiggle room, even an IEC socket. I'd personally make it a hair large than risk having to file it down. But Reel T. is right, the CNC should be able to cut it exactly as it's spec'd. When you get it done, please report back because I'm curious as well.

[Luthierwnc]

The holes you can make pretty tight. I leave another couple hundredths just so I don't have to ream the burrs.

The bends are much more of an issue. I programmed in a quarter inch bend radius to allow for the deflection. The line that shows the bend is neither the inside nor the outside of the chassis. IMHO, that line would be in the middle of the bend so you need to add a quarter inch of slop front and side (and an 1/8" depth) in getting your final dimensions.

This picture is frozen from a 3D image of the chassis I'll be putting in the cherry cab thread I posted. The bend line on the layout is very snug to the side flanges but in this shot you can see a gap between them. Welding fixes that but you can tell you need extra room. Ir you don't allow enough room for the deflection the metal really gets distorted. Since (unusually) I did the cab first, I've got to be extra careful not to make the thing too fat.

Hope this helps, Skip