HM 4.2.4 3D Printed Case

Chris Statton

New member
Can anyone tell me which stl file I want? Just built the heatermeter with thermocouple and need a case!
It all depends on what model Raspberry Pi you have

RPi Model A:
BOTTOM - 4.2.4-2L-TC-PiA-BOT-v1.2.stl
TOP - 4.2.4-2L-TC-PiA-TOP-v1.2.stl

RPi Model A+:
BOTTOM - 4.2.4-2L-TC-PiAp-BOT-v1.2.stl
TOP - 4.2.4-2L-TC-PiAp-TOP-v1.2.stl

RPi Model B:
BOTTOM - 4.2.4-2L-TC-PiB-BOT-v1.2.stl
TOP - 4.2.4-2L-TC-PiB-TOP-v1.2.stl

Hope that helps.

For others, Tom has used a great naming convention for the source files that makes it really easy to work out which files you need for your setup:

Example source file name: 4.2.4-2L-TC-PiB-TOP-v1.2.stl​
4.2.4-2L-TC-RPiB-TOP-v1.2
HM hardwareLCD LinesPit ProbeRPi VersionHalfRevision
2L - 2 LinesTC - ThermocoupleRPiA - Model ATOP - top
4L - 4 Linesprobe - ThermistorRPiAp - Model A+BOT - bottom
RPiB - Model B
 

GvdHoven

New member
Newby on the PID path here.. I have posted a question here, maybe you can take a look at it. I would like to get a case 3D printed, but i am from the Netherlands, and i don't know how long shipping takes and what it costs.

I found this website which lists all printers for my home town, but what type of printer should i look for, what material, what accuracy? I have a Pi model B so i should go for this one if i am correct:
RPi Model B:
BOTTOM - 4.2.4-2L-TC-PiB-BOT-v1.2.stl
TOP - 4.2.4-2L-TC-PiB-TOP-v1.2.stl
 

Andrew K

New member
I just had this built and the 3mm nuts definately did not fit. I had to drill bigger holes to make it work and some went to far so now I have some bolts I need to grind down. The printer is blaming the design. Have anyone else experienced the same thing?
 

Bryan Mayland

TVWBB Honor Circle
Well M3 nuts are 6.01mm across the points, 5.5mm across the flats. The holes in the model for the nuts are 6.6mm across the points, ~5.7mm on the flats. They're designed to be a tight fit, but in the perfect world they should be fine. My printer has a hard time printing them the right size though, because the filament shrinks a little when it is laid down, and the corners bend in a little. I use a soldering iron on the nuts to warm them up a bit and they slip right in. Tom's printer is superawesomeamazing though and can print it accurately.
 

Andrew K

New member
Well M3 nuts are 6.01mm across the points, 5.5mm across the flats. The holes in the model for the nuts are 6.6mm across the points, ~5.7mm on the flats. They're designed to be a tight fit, but in the perfect world they should be fine. My printer has a hard time printing them the right size though, because the filament shrinks a little when it is laid down, and the corners bend in a little. I use a soldering iron on the nuts to warm them up a bit and they slip right in. Tom's printer is superawesomeamazing though and can print it accurately.
Hmm wish i knew this before paying for something that didn't fit to spec. Would have chose my printer from 3dhubs a little more carefully. The printer is blaming the design. This is their response.

"I managed to get a measurement that I feel is pretty accurate from the STL file. I measured the distance across the flats of the nuts to be 5.70mm (.224"). A standard 3mm nut is 5.5mm across the flats (.217"). This should in theory give (.007") clearance for the nuts to seat in the holes. However, there are tolerance factors which can add up to the nut not fitting which is likely what happened in this case. I am a mechanical engineer and cut steel parts on multi-million dollars laser every day that usually hold right around +/-.005" or better. The average width of the human hair is about .004", very small. I think the designer of the parts may be asking for a bit much from the hardware almost everyone is using at a home use level. Some people may be get parts turn out fine because that print happened to be on the + side of the tolerance, while other people may get parts that are on the - side of the tolerance and have fit up issues. The designer could open up the distance across the nut flats another .020" and probably not have any effect on functionality of the part and guarantee fit up every time"
 
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Tom Kole

TVWBB Pro
Hey everyone, sorry I have been unresponsive. I am currently living between 2 places that are 200 miles apart and have largely been out of contact. Things will be back to normal in a few weeks....

The nut traps are designed to be tight, very tight. The last thing you want is for the nuts to slip. All you do is thread a nut onto the end of a screw and then use a hammer to gently set into place. The 2 nut traps for the through holes on the bottom of the case that don't have supports extending all the way to the top need to be supported on a wood or metal block before tapping the nuts in or else you can risk pushing them right through the plastic.

Tom
 
Printed case, what machine and what settings?

Here is the newest release of the Heatermeter 3D printed case to complement the 4.2.4 boards. We've tried to push the design forward to parallel some of the tremendous progress that Bryan has made with the new boards. This case went through many behind the scenes revisions and we must thank Bryan for all of his help with protoype testing as well as John Bostwick for his feedback.
What machine did you print your case on? What material and what settings?
 

Tom Kole

TVWBB Pro
Custom machine that I designed. I print in ABS and PLA, mostly PLA now because I like it better. Settings in 3d printing are sort of machine specific. In general, I use 0.3 mm layer heights and speeds around 100 mm/s.
 

Tom Kole

TVWBB Pro
"The designer could open up the distance across the nut flats another .020" and probably not have any effect on functionality of the part and guarantee fit up every time"
Or the nuts could spin every time resulting in useless prints. If the nuts couldn't be tapped in with a hammer then your printer should recalibrate his machine or reconsider using it as a retail service.
 

RalphTrimble

TVWBB Diamond Member
Recently Tom announced in another thread that he is going to have to limit his 3D printing for forum members due to time constraints. I thought I would post here in the Heater Meter case thread that I am available to do 3D printing of cases and/or dampers, if anyone is in need you can contact me at rotodamper AT hotmail DOT com
 

Bryan Mayland

TVWBB Honor Circle
Or the nuts could spin every time resulting in useless prints. If the nuts couldn't be tapped in with a hammer then your printer should recalibrate his machine or reconsider using it as a retail service.
To back up what Tom said, I just printed a bottom with 0.09mm expanded nut traps (0.18mm flat to flat/pint to point) and the screws went in until they started to hit some tension then the nuts started spinning freely in the holes. Now they're stuck in there forever and I can't get the case apart without destroying the bottom piece.
 

RalphTrimble

TVWBB Diamond Member
Ahh the nut traps... they can be as painful as it sounds.... lol
That's why when I was working with the HMv4.2.3 prototype and knew I would be opening the case often to access the board I designed the sliding back case with NO SCREWS to screw with....
 

Tom Kole

TVWBB Pro
My HMs are put in a case and stay in that case without ever needing to open them. By having a case that screws together, top to bottom, you can support the HM in ways that your "sliding back" case could never do. I can't think of any reasons why I would need to open my HM so I believe that protection is the prime objective when designing a case. If you print the case with the nut traps sized appropriately, you can easily tap in the nuts and will not have problems with spinning nut traps. If you want to risk damaging your HM if you drop it, then go with a more accessible option.
 

RalphTrimble

TVWBB Diamond Member
Your case is very solid Tom, I'm not knocking the design, concept, your priorities etc... but dealing with the nut traps and allen screws on the initial assembly can be a bit tough. I'm sure you've done enough to where you have the printing perfected and the tools/method/technique for assembly down pat and don't struggle like the average guy doing it the first time might.

Like I said, I put together the screwless sliding back design while I was working with the prototype HMv4.2.3 and opening my HM regularly to work on the board, since I have been using it I've grown used to having easy access to the boards. Like when someone is having trouble with a build and needs help, I can pop my boards out of the case in a second flat and examine the parts in question to help troubleshoot the problem. Or if I want to tinker with the rPi on another project for a bit, same deal, in my hands in an instant, back on the HM just as fast....

...but again, I get your point and design intent with your case... lock everything down solid, support the board(s) and hold everything in place to make the HM like an appliance that can go though hell and be unaffected, and you have achieved that well, in a nice small package... I have indeed dropped HM's in your case and they never skipped a beat, I've dropped the sliding back case a couple times as well and never had a problem with that one either.
 

Peter F

TVWBB Fan
My experience with Tom's cases (I have printed about a dozen now) is that the nuts fit very snugly but I never have to use any excessive force or heat to push them in. In some cases I need to pull the nuts in using a 30mm screw and a washer but normally I can just push them in far enough so that the normal 25mm screws will catch the nuts and pull them in until they are fully seated.

I wonder if the others holes in the case will fit if the 3D printer is so poorly adjusted that the nuts won't fit anymore.
 

JHalasz

TVWBB Fan
those nuts and that allen stock killed my fingers, I went with Ralphs slide back case, no hardware required.
 

RalphTrimble

TVWBB Diamond Member
Peter F, I used the same technique, I try to tap them in place and hope the allen screw reaches, but generally have to pull them into place using the allen screw before I assemble the case. Which means I had to run the allen screws in and out once before I assemble the case and again after, and damn near wore a hole in my thumb with the allen wrench! LOL (not really, but my thumb was sore). The good part is once they are seated they generally don't go anywhere. I had it on my list to cut down an allen wrench to clamp into my drill to make this go easier and then the idea for a screwless case came to mind and that was the end of that...
 

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