ruffrecords

Is the gap necessary
« on: April 08, 2018, 10:50:46 AM »
The Eurocard rack mechanical standard has a 2.54mm (0.2 inch) gap between the front vertical edge of the PCB and the back face of the front panel. I have no idea why this is so and I question if it is necessary. It is a real pain when designing PCBs with controls that are on the PCB but are also attached to the front panel. You either use a standard footprint and accept  that part of the silk screen will be off the board ( and have to tell the PCB fab house it is OK when the inevitably query it) or make special footprints just for this purpose.

Also, the PCB is attached to the front panel using a pair of special die castings that enforce this gap. The have a ridge that the PCB front edge mates against and the die casting is 2.5mm thick to enforce the spacing:



Also, the die castings are expensive and waste a lot of front panel space.

Some time ago Abbey suggested using these cheaper simpler tapped cubes instead of the die castings:

http://uk.farnell.com/ettinger/05-60-223/cube-standoff-threaded-m2-5-m3/dp/1466865

The interesting thing is if you fit one to a PCB is protrudes by 2.24mm so it very nearly meets the standard (it is 0.3 mm = 7.62 mil short) but of course it does not have the shoulder the die casting has so the PCB sort of flaps in the wind.

So it occurred to me all I would need do is make the PCB 2.24mm longer and the PCB front edge would be flush with the front panel. So I could use these cheaper  fixings and not have to worry any more about PCB footprints. The question remains; why does the Eurorack standard have this 2.54mm gap in the first place? Have I missed something?

Cheers

Ian
www.customtubeconsoles.com
https://mark3vtm.blogspot.co.uk/
www.eztubemixer.blogspot.co.uk


'The only people not making mistakes are the people doing nothing'


Re: Is the gap necessary
« Reply #1 on: April 08, 2018, 07:00:31 PM »
The question remains; why does the Eurorack standard have this 2.54mm gap in the first place? Have I missed something?

Hello Ian

This gap is used by label holder and/or card locker/extractor when euro card is not hooked to front panel.

Best
Zam

ruffrecords

Re: Is the gap necessary
« Reply #2 on: April 09, 2018, 02:49:20 AM »
Hello Ian

This gap is used by label holder and/or card locker/extractor when euro card is not hooked to front panel.

Best
Zam

Ah, that makes sense. So there is no reason to retain it if I do have a front panel and I don't use labels or an extraxtor.

Cheers

Ian
www.customtubeconsoles.com
https://mark3vtm.blogspot.co.uk/
www.eztubemixer.blogspot.co.uk


'The only people not making mistakes are the people doing nothing'

Re: Is the gap necessary
« Reply #3 on: April 09, 2018, 09:12:57 AM »
So there is no reason to retain it.

I'll say yes and no  :)
Sticking to the standard let the compatibilities, especially the ones you don't thing about today.
Extending to 100x162.54 won't hurt for your use case as I see it now.

Best
Zam

ps:for the record, pict attached of typical label holder

ruffrecords

Re: Is the gap necessary
« Reply #4 on: April 09, 2018, 11:43:13 AM »
OK, I had not seen a label holder like that before. As you say, not an issue for my use case.

Cheers

ian
www.customtubeconsoles.com
https://mark3vtm.blogspot.co.uk/
www.eztubemixer.blogspot.co.uk


'The only people not making mistakes are the people doing nothing'

pvision

Re: Is the gap necessary
« Reply #5 on: April 09, 2018, 06:57:20 PM »
Looks like a Studer card - the A800 had cards just like that

ruffrecords

Re: Is the gap necessary
« Reply #6 on: April 09, 2018, 07:03:44 PM »
Looks like a Studer card - the A800 had cards just like that

Yes it reminds me of the cards in a Studer B67 I once had but that was long before I got into Eurorack mechanics.


Cheers

Ian
www.customtubeconsoles.com
https://mark3vtm.blogspot.co.uk/
www.eztubemixer.blogspot.co.uk


'The only people not making mistakes are the people doing nothing'

Re: Is the gap necessary
« Reply #7 on: April 10, 2018, 07:14:54 AM »
Yes it reminds me of the cards in a Studer B67

Bingo
B67 record amp...

Best
Zam

ruffrecords

Re: Is the gap necessary
« Reply #8 on: April 10, 2018, 11:28:40 AM »
Ooooh. Do I get a prize?

Cheers

Ian
www.customtubeconsoles.com
https://mark3vtm.blogspot.co.uk/
www.eztubemixer.blogspot.co.uk


'The only people not making mistakes are the people doing nothing'

Re: Is the gap necessary
« Reply #9 on: April 10, 2018, 11:35:52 AM »
Ooooh. Do I get a prize?

Cheers

Ian

I can drill the rivet and send you the label holder  :P
But now I suspect you'r cheating as you claim never seen those holders and then recognise the specific card  8)
Best
Zam


ruffrecords

Re: Is the gap necessary
« Reply #10 on: April 10, 2018, 01:04:56 PM »
I can drill the rivet and send you the label holder  :P
But now I suspect you'r cheating as you claim never seen those holders and then recognise the specific card  8)
Best
Zam

LOL. I had a B67 15 years ago.I rarely if ever had cause to remove a card so the fact it had a label holder would not have been remembered. And I had no idea it was part of the current Eurorack standard. I am not sure if any of the current manufacturers literature even mentions it.

Cheers

Ian
www.customtubeconsoles.com
https://mark3vtm.blogspot.co.uk/
www.eztubemixer.blogspot.co.uk


'The only people not making mistakes are the people doing nothing'

Re: Is the gap necessary
« Reply #11 on: April 10, 2018, 08:42:53 PM »
And I had no idea it was part of the current Eurorack standard. I am not sure if any of the current manufacturers literature even mentions it.

Neither I know, your initial question just light my mind and I correlate with those plastic part I have all around at my eurocards rack.
It's a pure deductive logic...
Best
Zam

Potato Cakes

Re: Is the gap necessary
« Reply #12 on: April 10, 2018, 10:19:36 PM »
Ian,

Since you live in the U.K., you should know that one must always mind the gap...

Sorry, I couldn't resist.

Carry on.

Paul

ruffrecords

Re: Is the gap necessary
« Reply #13 on: April 11, 2018, 07:38:54 AM »
Ian,

Since you live in the U.K., you should know that one must always mind the gap...

Sorry, I couldn't resist.

Carry on.

Paul
[/qu

Not surprisingly, that had occurred to me, but I can see no way of expressing the unique cadence of the announcer in writing.

Minduh, the gapuh?

Cheers

Ian
www.customtubeconsoles.com
https://mark3vtm.blogspot.co.uk/
www.eztubemixer.blogspot.co.uk


'The only people not making mistakes are the people doing nothing'


 

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