Bl..dy Data Sheets

I recently bought some vertical PCB mounting toggles from CPC (a branch of Farnell). I got them from CPC because in the quantities I wanted they were much cheaper than Farnell. There was no data sheet for the part on the CPC site but there is one on the Farnell site:

http://www.farnell.com/cad/94994.pdf

As you will see, the manufacturer's data sheet quite clearly shows the spacing between vertical rows of this toggle switch is 0.16 inches. So I duly layed out my PCB using these dimensions and, guess what, when the PCBs arrive the switches don't fit! Turns out the spacing between the rows is actually 0.2 inches (I measured it to be sure) despite what the data sheet says.

That just cost me £100 in unusable PCBs    Can't blame Farnell or CPC.

The moral I guess is don't trust the data sheet for mechanical parts before you lay out your PCB.

Cheers

Ian

Bummer, but yes that's what is better, wait for the parts and see for yourself....

EDIT: Heuhhhh where do you see 0.16 inches? I have 0.200 (5.08mm) on your datasheet  

Oh so stupid the PC mount shows 0.16, wile the back view shows 0.200, but it's the norm to be in multiples of 0.1 most of the time, but what a bummer, i would have done the same mistake for sure....
I can see on the Back view that the pins at the back are off centered (Correct me if i'm wrong) that's where you got screwed right?

I've been burned by too many inaccurate "spec sheets." My motto: I'll believe it when I see it.

Sorry to hear about your loss. Do you think it's worth finding other parts that fix, just so they're not a complete waste?

zayance said:

entered (Correct me if i'm wrong) that's where you got screwed right?

Click to expand...

Pretty much. The 0.2 inch dimension on the top right pic looks to me to be across the pins not centre to centre and when I saw the PC pins pic that just confirmed it in my mind.

I have a nasty feeling that all PCB mount togles are 0.2 separation so I don't hold out much hope for finding a part that fits the current PCB.

I have toyed with the idea of drilling a separate set of holes but they would be damn close. I also tested bending the pins on a couple but I am concerned about reliability implications of doing that. Right now I have bit the bullet and sent off a revised layout.

Cheers

Ian

ruffrecords said:

The moral I guess is don't trust the data sheet for mechanical parts before you lay out your PCB.

Click to expand...

I don't mean to be smug. When I am designing a pcb or any other mechanics I have my vernier gauge in one hand and all the components in front of me. Bitten too many times in early years of my career. Of course there are still times we all make mistakes.

sahib said:

ruffrecords said:

The moral I guess is don't trust the data sheet for mechanical parts before you lay out your PCB.

Click to expand...

I don't mean to be smug. When I am designing a pcb or any other mechanics I have my vernier gauge in one hand and all the components in front of me. Bitten too many times in early years of my career. Of course there are still times we all make mistakes.

Click to expand...

I agree. When I was working (I am now retired) I had guys who did PCB layouts for me and I never had to worry about that sort of thing. Doing it (all) yourself is a new learning curve and (apart from a few cock ups on the way) I love it.

Cheers

Ian

If you ask nicely they might take them back?
I've made a similar mistake before and Rapid took the parts back.
Customers always right and all that...

sahib said:

ruffrecords said:

The moral I guess is don't trust the data sheet for mechanical parts before you lay out your PCB.

Click to expand...

I don't mean to be smug. When I am designing a pcb or any other mechanics I have my vernier gauge in one hand and all the components in front of me. Bitten too many times in early years of my career. Of course there are still times we all make mistakes.

Click to expand...

Are you sure we aren't twins? ;D

Frank

Maybe I'm just lucky, but I haven't found many (any?) clearly wrong data sheets, while I have seen a lot of confusing dimensions given in both inches and centimeters.

If anything I am pleased with how often using computer based design aids, everything pretty much fits and comes together the first time. Not my experience in the bad old days, where the first cut prototype was mostly to identify what hits what.

JR

PS: I can't measure fine dimensions well enough to build PCB footprints for these SMT parts I can barely see.... Of course trust but verify before going to full production.