3d printed hinge block

[Victor Burry]

how would a couple of printed blocks of abs or pla with a bolt hole hold up to being used as a hinges?

[Glen Beestone]

Depends on the application but ABS is pretty strong stuff.
For best results try a good infill and ensure the hinge bolt is 90° to the layers
I.e it goes down through the layers and is not parallel to them. Otherwise the leverage from it could lead to them delaminating

G

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On 20/06/2018, 14:19 'Victor Burry' via North East Makers <north-ea...@googlegroups.com> wrote:

how would a couple of printed blocks of abs or pla with a bolt hole hold up to being used as a hinges?

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[Victor Burry]

im trying to make 2 pivot/attachment points for a skateboard sidecar before the end of next month, originally i was going to get it cut from nylon at a plastic fabrication place but after 3 weeks of chasing they finally admitted that they couldn't do it unless i paid a hefty additional charge so i'm hoping i can use the makerspace printers with help?

[Glen Beestone]

Ok that sounds like a fairly heavy duty application.
Might be best CNCd from something like a block of HDPE

We have a CNC too so maybe someone can help you with that and you can't run both approaches

G


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[David Pye]

Eek. How much load are you expecting this to take?

[Victor Burry]

15 to 20kg at a guess

[David Pye]

Personally I think you are asking quite a lot of a 3d printed click here, and I suspect it will fail on you....

Even the plastics with stronger layer adhesion eg PETG would be pushing it.

I'd say the ONLY 3d printed plastic that might have a shot is nylon and I don't think the spaces printers have hot ends that can handle it.

I think Glen's CNC suggestion might be your best option.

David

[Victor Burry]

That sounds cool, where do i get a block of HDPE from and can the CNC cut through a 20mm thickness?

[Glen Beestone]

Bau plastics


But, Just a thought. Does it have to be plastic. Would aluminium be better ?

G

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[Glen Beestone]

*Bay Plastics

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[Victor Burry]

i don't know, i figured a metal bolt in a metal block wouldn't spin that well and even if it did it might be noisy. i also assumed plastic would be cheaper and easier to work with...

[Danny Walker]

I guess you must be the person I spoke to at Maker Faire about this? Unless skateboard sidecars are suddenly very popular :)

Playing devil's advocate slightly here - I'd just try it. Designing one will only take an hour, and then an evening's worth of printing time and a few pence worth of plastic. Make one, hang some weight from it, see when it breaks. I've had some fairly surprising results load testing some PLA components before. If it turns out to be far too weak, your investment in the idea was minimal anyway, and then plan B can be to mill it out of aluminium/Delrin/something. Load testing it won't tell you much about whether it'll fatigue and snap after 1/2 mile of skating, but it'll give you an idea about whether 3D printing is even nearly suitable for the job.

Danny

[Victor Burry]

yeah that'd be me. thinking about it i'm not sure how much weight would actually be on the hinge blocks, the total weight of the sidecar plus contents could be up to 20kg however that won't entirely be carried by the hinges as it'll be supported by the wheel as well. if i need to carry the thing at any point i'll likely attempt to pick it up by the sidecar side meaning that at that point the most they would be carrying is 5 or 6kg on the board side...

[Victor Burry]

i've gone and bought a bit of UHMWPE because it was listed as more frictionless than the standard HDPE, i hope it's still suitable for CNC

[Ed Bisdee]

skateboad sidecar? is this a skateboard with a sidecar hanging off it or a sidecar using skate wheels and trucks for a bike/motorbike?

[Victor Burry]

something like this, i've got a mountainboard wheel for the sidecar which i want to try mounting inside the frame if i can. if all goes to plan the frame will be made from welded stainless steel square tube, drilled for the pivots, wheel bolt and about 4 small vertical bolts so that i can swap out plywood platforms with different attachments. the plan for first platform is to mount a medium sized PA speaker and take it along to the 'Let's Ride' family bike ride in Newcastle at the end of July :D

[Jonathan Powell]

If friction is going to be a problem with metal bolts then why not use some bearings. You could machine a block of plastic to take a couple of press fit bearings. There would then be minimal friction on the shaft.

[Victor Burry]

that is the plan eventually but for now i couldn't find button head socket M5 bolts long enough to go through a block thick enough to hold bearings, plus the baseplate, plus the shockpads, plus the deck and still have enough thread left for the nuts. as long as this works for 1 event then i can take my time trying to find those elusive extra long bolts and do the bearing upgrade...

[David Pye]

Slightly OT, but good place for bolts - M&S fastenings, which is in Newburn:

Newburn Industrial Estate, Shelley Rd, Newcastle Upon Tyne,Tyne And Wear, NE15 9RT 

David

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[Victor Burry]

not sure what the normal amount of time is to wait for a bit of plastic to be cut and posted but i'm still waiting...

[Victor Burry]

thanks, i'll keep this place in mind