Tinning a Brass Plate

[cgunn]

I am currently involved in a design project requiring a new/copied terminal block. The setup I am interested in involves 2 brass inserts connected by press fit into a thin brass plate approximately 1/2" long. A wire is than soddered to the plate (b/w the two inserts). Sounds simple enough right? Well, a fellow competitor who has been around the block a few more times uses a copper plate to connect the 2 brass inserts. To me, the use of copper plating seems a waste of money if you are attaching it to brass inserts and screws... Also, they also use a tin plating on the piece of copper...

So this brings me to my question. Does the tin plating matter?

The inserts are not plated, copper and brass are not very dissimilar metals. Would you recommend tin plating (brass inserts not to be plated) and or use copper for the connecting plate
I appriciate any input. Thanks.

P.S. Copper inserts are not an option.

 

[Lewish]

I don't have a clue what you are describing. Do the inserts have threads for screws? What does this thing do? What are you really trying to accomplish?

 

[cgunn]

Lewish,

This is a for a simple terminal block. The inserts are threaded and are headed mubux A, brass 80 threaded. Brass 80 machine screws will be threaded into the inserts to hold a set of postive wires, like wise, the other side of hte terminal block will hold a set of negative wires, to create a "series" effect. (much like a standard outlet, ie. over head light fixture).

An 18 gauge brass plate is going to be used to ensure there is a contact between the two inserts (wires). Either end of the plate will have a press fit hole to accommidate for each insert. In the center of the brass plate,a wire is soldered to allow for current to the apparatus (ie heating source).

So my question remains, will "tinning" the plate and or using a copper plate have any effect on the terminal blocks efficiency?

Cgunn

 

[Lewish]

OK, now that makes much more sense. Without knowing what voltage and current levels you are operating at, a general answer would be NO. People generally plate the terminal blocks to prevent oxidation of the brass and for prevention of scarring by tightening the screw. Most times, however, nickel, not tin is used for the plating. Tin is rather soft. Nickel is very hard. Nickel will keep the wire from gouging into the soft brass.

 

[cgunn]

That's the answer I was looking for. I didn't see much, if any benefit to coating only the plate.

A little more detail regarding the "tinning" procedure (I was informed this morning) consists of 0.0002" of nickel base, followed by 0.0002" tin top coat (for soldering).

However, as I had mentioned before, the threaded inserts and screws being used are bare brass. Also, they are being press fit into the plating, thus removing most of nickel/tin coating from the contact surface.

Thanks for the input.