Face Plate attachment alternatives (and reasons)

[Chris Smith]

I confess to being a stickler for fit and finish. And the bright screw heads on the front panel are something I find slight disconcerting.

Now, I was going through the construction notes, and I *think* I understand that when you put the screws through the acrylic panel (through pre-drilled holes!) there is nothing directly supporting the panel behind those screws. (If I am right, then I also think the instructions should caution against overtightening those screws.)

My thought was to do *almost* the same thing, but instead of drilling holes in the front panel, I would first drive the screws slightly deeper than the panel support edge. Then I would put small magnets on on the tops of the screws, top them with a small amount of epoxy or cyanoacrylate, and place the panel in position, touching the ready-to-glue magnets. Once the glue has attached the magnets to the front panel, the panel can be easily popped in and out, and should stay in place with the magnets holding the (assumed steel!) screws. My favourite source of thin rare-earth magnets is the closable flaps on cell phone belt cases, which often have two small, thin, round magnets that stick to a steel plate on the other side.

This would be an easy mod, and would also entirely avoid drilling the acrylic.

Finally, it would allow for two new capabilities - one, you can easily pop out the front panel to show off the workmanship inside. There's some nice design in there, and it would be great to show it off sometimes.

The other idea came to me last night, and I spent ten minutes making notes on a copy of the front panel. There are enough LEDs - in a nice arrangement - to support the internal model of the 6502 processor. If front panels could be easily swapped out, then it would be simple matter of using a different software simulator to create a "6502 Machine", with all of it's internal register workings exposed.

There are way more registers than LEDs in the Z80 and the 8080, but there might be many other classic microprocessors and microcontrollers that would fit in the existing front panel arrangement.

[Oscar Vermeulen]

Chris,

On 16 July 2015 at 17:25, Chris Smith <cjs...@gmail.com> wrote:

Now, I was going through the construction notes, and I *think* I understand that when you put the screws through the acrylic panel (through pre-drilled holes!) there is nothing directly supporting the panel behind those screws. (If I am right, then I also think the instructions should caution against overtightening those screws.)

Er, correct, although the acrylic is supported in that area by the switch mounts. So overtightening is a risk, but not a very big risk.

[...] Then I would put small magnets on on the tops of the screws

Brilliant! I puzzled - for exactly the same reasons - with magnets as a fixing mechanism. I tried using the type of magnet 'locks' used for kitchen cabinets, but found out there's not enough space between PCB and acrylic to mount such magnets. Still have a bag full of them :(

But mounting a flatter magnet (you even have flat magnets with a mount hole in them on Aliexpress I saw) on the place where the front panels screws used to go is the optimal solution.

My favourite source of thin rare-earth magnets is the closable flaps on cell phone belt cases, which often have two small, thin, round magnets that stick to a steel plate on the other side.

And that may well be the solution. Do you have a source, on Aliexpress or something?

It requires sticking either the magnet or a metal bit onto the back of the acrylic. That should be OK, the paint seems reasonably strong.

Regards,

Oscar.

[Chris Smith]

I'm not usually interested in the quantities that AliExpress would justify.

But this -- http://www.aliexpress.com/item/100pcs-Strong-Round-Magnets-Dia-8mmx1-5mm-N35-neodymium-magnet-rare-earth-magnet/1909970385.html

might fill the bill for a large order. That works out to about $0.11 for two magnets.  And another option for attachment of the magnets is double sided tape.  I don't think it would be as strong as epoxy, but it might be enough -- and if you're thinking of a kit addon or mod, one inch of two sided tape is easier to pack than glue.

Locally, I like this outlet ... http://www.leevalley.com/en/wood/page.aspx?p=32065&cat=1,42363,42348  (which is a very fun place just to browse).

My only concern would be that even the smallest ones are too strong - but if it's just for me, I have a dozen or so scavenged magnets from phone cases, and "blinky badges" -- http://www.alibaba.com/product-detail/led-magnetic-button-badge-with-led_1679832088.html -- these are often given away for free at events, and the magnetic ones usually have two small rare-earth disc magnets in the back to hold them to light clothing.

The other small scale source are "magnetic push pins" -- available many, many places, as an office supply item. This can be great for people in more remote areas without easy access to the usual tech sources.

On Thursday, July 16, 2015 at 1:23:17 PM UTC-4, Obsolescence wrote:

Chris,

On 16 July 2015 at 17:25, Chris Smith <cjs...@gmail.com> wrote:

Now, I was going through the construction notes, and I *think* I understand that when you put the screws through the acrylic panel (through pre-drilled holes!) there is nothing directly supporting the panel behind those screws. (If I am right, then I also think the instructions should caution against overtightening those screws.)

Er, correct, although the acrylic is supported in that area by the switch mounts. So overtightening is a risk, but not a very big risk.

[...] Then I would put small magnets on on the tops of the screws

Brilliant! I puzzled - for exactly the same reasons - with magnets as a fixing mechanism. I tried using the type of magnet 'locks' used for kitchen cabinets, but found out there's not enough space between PCB and acrylic to mount such magnets. Still have a bag full of them :(

But mounting a flatter magnet (you even have flat magnets with a mount hole in them on Aliexpress I saw) on the place where the front panels screws used to go is the optimal solution.

I'm not usually interested in the quantities that AliExpress would justify.

But this -- http://www.aliexpress.com/item/100pcs-Strong-Round-Magnets-Dia-8mmx1-5mm-N35-neodymium-magnet-rare-earth-magnet/1909970385.html

might fill the bill for a large order. That works out to about $0.11 for two magnets.  And another option for attachment of the magnets is double sided tape.  I don't think it would be as strong as epoxy, but it might be enough -- and if you're thinking of a kit addon or mod, one inch of two sided tape is easier to pack than glue.

Locally, I like this outlet ... http://www.leevalley.com/en/wood/page.aspx?p=32065&cat=1,42363,42348  (which is a very fun place just to browse).

My only concern would be that even the smallest ones are too strong - but if it's just for me, I have a dozen or so scavenged magnets from phone cases, and "blinky badges" -- http://www.alibaba.com/product-detail/led-magnetic-button-badge-with-led_1679832088.html -- these are often given away for free at events, and the magnetic ones usually have two small rare-earth disc magnets in the back to hold them to light clothing.

The other small scale source are "magnetic push pins" -- available many, many places, as an office supply item. This can be great for people in more remote areas without easy access to the usual tech sources.

 

My favourite source of thin rare-earth magnets is the closable flaps on cell phone belt cases, which often have two small, thin, round magnets that stick to a steel plate on the other side.

And that may well be the solution. Do you have a source, on Aliexpress or something?

It requires sticking either the magnet or a metal bit onto the back of the acrylic. That should be OK, the paint seems reasonably strong.

I figured that I would glue (double sided tape?) the magnets to the front panel. The screws themselves would be the "metal plate", with the notable advantage that the height can be adjusted up and down.

It's just a guess on my part, but the wide availability of screws likely means that those two M3x30 screws are likely cheaper than any custom bit of metal plate.

 

Regards,

Oscar.

[Dylan McNamee]

I'm 90% done, and happy with my results so far (photo posted in the "share your photos" page). I'm going with the Friction-fit option on the panel itself, and instead of screwing the blocks into the box, used two counter-sunk magnets in the blocks, then taped two of the same magnets to the back of the box, slightly offset to the right to get it snug.

The magnets I used are from this amusingly-named Chinese importer (who I've had very good luck with):

http://www.banggood.com/50pcs-N50-D-103mm-Strong-Ring-Magnet-3mm-Countersunk-Hole-p-940059.html

best,

dylan