Wanted Mechanical Drawing / Drill Holes Plastic-Electronic-Project-Box - Page 1
Forum section: electronics / projects

author: diyaudio
author_rank: Frequent Contributor
timestamp: February 04, 2017, 04:06:20 pm
content: Does anyone here have the mechanical drawing for this plastic box enclosure I have searched all over the internet and found nothing useful. I need it to start a PCB design.https://www.aliexpress.com/item/In-stock-Waterproof-100-x-68-x-50mm-Plastic-Electronic-Project-Box-Enclosure-Case/32663744145.html?spm=2114.40010508.4.34.2x47Sg>

author: Pack34
author_rank: Frequent Contributor
timestamp: February 04, 2017, 07:25:03 pm
content: Do you need a mechanical model of it, or just the mounting hole spacing to mount a PCB?

author: basinstreetdesign
author_rank: Frequent Contributor
timestamp: February 04, 2017, 07:51:05 pm
content: If I were you I would start your layout with the given internal dimensions and outline the board for about 2mm less on all sides, so 88mm x 57mm. Then estimate the positions of the mounting screws and put a circle at each of those positions allowing a generous berth around each but do not put centers yet.Next, layout your circuit and get it fabbed (or do that yourself). Wait until you have the box in your hand so you can measure the exact positions of the mounting standoffs, drill those holes in your PCB. Finally build it and test it.

author: Benta
author_rank: Super Contributor
timestamp: February 04, 2017, 07:58:46 pm
content: At a cost of $2.47, I'd just buy one and measure it. There has to be a limit to cheapness.

author: diyaudio
author_rank: Frequent Contributor
timestamp: February 04, 2017, 08:00:52 pm
content: Quote from: Pack34 on February 04, 2017, 07:25:03 pm100%, just the mounting hole spacing to mount the PCB. I used a paper cutout but I cannot get the land markings and round edges accurate, I'm worried that my measurements will end up screwing the mounting holes.

author: Benta
author_rank: Super Contributor
timestamp: February 04, 2017, 08:18:47 pm
content: This is an instance where a compass divider is extremely useful:http://goodsjapan.com/ekmps/shops/goodsjapan/images/craft-sha-leathercraft-wing-divider-leather-scratch-compass-w-spring-15cm-171-p.png

author: Ian.M
author_rank: Super Contributor
timestamp: February 04, 2017, 08:29:06 pm
content: Do you have the box in hand? If so, assuming you've got a mill with DRO or a CNC mill with a manual 'jog' mode, clamp it on the table and use a conical tipped probe to 'pick up' the coordinates of each mounting boss. Otherwise, you can measure hole to hole using calipers to transfer the measurement, and also measure the bore diameter of each, then plot the hole positions using the diagonals to confirm accuracy.If you use a close tolerance hole at one corner, slot the two holes at adjacent corners and make the hole at the far corner oversize, you can easily accommodate any small measurement errors and also allow for differential thermal expansion between PCB and box . . . .

author: diyaudio
author_rank: Frequent Contributor
timestamp: February 04, 2017, 08:47:14 pm
content: I'm going the Calipers route, looks like its the only simple way to do it. I'm just being lazy asking for the drawing file.

author: Benta
author_rank: Super Contributor
timestamp: February 04, 2017, 08:50:59 pm
content: QuoteThat's one heck of an assumption, and if it were the case, I'm sure the OP would have used this option.QuoteNo, the problem with this kind of measurement is, that standard caliper jaws do not fit in the enclosure.Using compass dividers is based on my machining experience. Getting the points centered on the holes by eyesight usually yields a tolerance of 0.1 mm for an inexperienced user, a trained eye can do even better.Measuring the distance between the points afterwards is a no-brainer.