Battery Buggy B

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windu34
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Re: Battery Buggy B

Postby windu34 » April 29th, 2018, 7:16 pm

MadCow2357 wrote:I have decided that I will have a 5 CF rod bed in the middle, but I have yet to see if I have enough CF for an extra 11.5 cm CF rod(I may switch to 11 though). I bought 1 meter sticks (4).

I will see if I can make the holes 3 cm deep. Do I need there to be some material behind the rod so it does not portrude outward? You will probably understand my question if you look at my CAD file.

Windu what do you mean when you say that screw threads gripping into the material won't be enough? So should I make threaded holes?

It doesnt matter if you have material behind the rod or not. Threads that are 3D printed are typically not very strong and VERY hard to get the right tolerances not to mention complex to design. I suggest avoiding threads all-together and using a nut-bolt fastenerhttp://championpartsonline.com.au/index.php?route=product/product&product_id=18713
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Re: Battery Buggy B

Postby MadCow2357 » April 30th, 2018, 3:55 am

Thanks for warning me about the threaded holes windu! That's one mistake that you helped me to avoid :D .

So, after you push the rods in, do you glue them? And with what glue? The holes in my 3D printed parts seem to be a little large, even though I made them to be exactly 8mm. I may not be able to smash the rods in and be done, because they will mostly likely not hold without glue. :?:
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Re: Battery Buggy B

Postby shrewdPanther46 » April 30th, 2018, 4:43 am

epoxy
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Re: Battery Buggy B

Postby kylg » April 30th, 2018, 5:19 am

balsa cement
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Re: Battery Buggy B

Postby windu34 » April 30th, 2018, 6:45 am

MadCow2357 wrote:Thanks for warning me about the threaded holes windu! That's one mistake that you helped me to avoid :D .

So, after you push the rods in, do you glue them? And with what glue? The holes in my 3D printed parts seem to be a little large, even though I made them to be exactly 8mm. I may not be able to smash the rods in and be done, because they will mostly likely not hold without glue. :?:

If the holes arent so tight that you need a hammer to get the carbon in, then you need to redesign and reprint the part. You should not be able to move the rods once they are hammered in. I always adding a small amount of liquid 2-part epoxy to the rods and plastic AFTER I have ran the vehicle multiple times and I am certain that the frame is relatively straight and the way I want it. You will not and should not be able to adjust the frame after you hammer in the rods and epoxy them. It is crucial that the rods are tight in the holes without the epoxy
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Re: Battery Buggy B

Postby cheese » April 30th, 2018, 4:07 pm

windu34 wrote:
MadCow2357 wrote:Thanks for warning me about the threaded holes windu! That's one mistake that you helped me to avoid :D .

So, after you push the rods in, do you glue them? And with what glue? The holes in my 3D printed parts seem to be a little large, even though I made them to be exactly 8mm. I may not be able to smash the rods in and be done, because they will mostly likely not hold without glue. :?:

If the holes arent so tight that you need a hammer to get the carbon in, then you need to redesign and reprint the part. You should not be able to move the rods once they are hammered in. I always adding a small amount of liquid 2-part epoxy to the rods and plastic AFTER I have ran the vehicle multiple times and I am certain that the frame is relatively straight and the way I want it. You will not and should not be able to adjust the frame after you hammer in the rods and epoxy them. It is crucial that the rods are tight in the holes without the epoxy


Yeah I print my parts about 0.1 mm bigger. The tolerance of my 3D- printer is a little more, so I spent a couple hours sanding all my parts, so that it would fit very tight with gentle hammer taps. I use #6 screws and nuts for literally everything. It surprisingly doesn't add too much weight to make a significant difference and the amount of strength and mental stability for me is a plus.
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Re: Battery Buggy B

Postby MadCow2357 » April 30th, 2018, 5:03 pm

cheese wrote:
windu34 wrote:
MadCow2357 wrote:Thanks for warning me about the threaded holes windu! That's one mistake that you helped me to avoid :D .

So, after you push the rods in, do you glue them? And with what glue? The holes in my 3D printed parts seem to be a little large, even though I made them to be exactly 8mm. I may not be able to smash the rods in and be done, because they will mostly likely not hold without glue. :?:

If the holes arent so tight that you need a hammer to get the carbon in, then you need to redesign and reprint the part. You should not be able to move the rods once they are hammered in. I always adding a small amount of liquid 2-part epoxy to the rods and plastic AFTER I have ran the vehicle multiple times and I am certain that the frame is relatively straight and the way I want it. You will not and should not be able to adjust the frame after you hammer in the rods and epoxy them. It is crucial that the rods are tight in the holes without the epoxy


Yeah I print my parts about 0.1 mm bigger. The tolerance of my 3D- printer is a little more, so I spent a couple hours sanding all my parts, so that it would fit very tight with gentle hammer taps. I use #6 screws and nuts for literally everything. It surprisingly doesn't add too much weight to make a significant difference and the amount of strength and mental stability for me is a plus.

I designed 8mm holes for my 8mm CF rods. The holes are not shrinking, they seem to be getting bigger. Why is that? Would it have something to do with the different cooling processes of ABS and PLA? Dunno. :?:
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Re: Battery Buggy B

Postby cheese » April 30th, 2018, 5:27 pm

Sometimes the orientation of your print makes a difference as there will be different tolerances in different directions.
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Re: Battery Buggy B

Postby MadCow2357 » May 1st, 2018, 7:23 am

I guess I will just tape the rods to the 3D printed connectors temporarily if they are not completely tight. Then, when I am certain on what I am going to do, then I will glue/epoxy them in.
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Re: Battery Buggy B

Postby PM2017 » May 1st, 2018, 8:29 am

MadCow2357 wrote:I guess I will just tape the rods to the 3D printed connectors temporarily if they are not completely tight. Then, when I am certain on what I am going to do, then I will glue/epoxy them in.

I tried this with MTV this year and it did not work.
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Re: Battery Buggy B

Postby MadCow2357 » May 1st, 2018, 11:48 am

Well then I just have to cross my fingers that the 3d printed holes come out very nicely. :D
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Re: Battery Buggy B

Postby Akshu007 » May 4th, 2018, 6:57 am

Has anyone tried using a sliding Potentiometer instead of a microswitch, to gradually slow down the vehicle and thus not cause any drifting? The Wingnut can push the protruding knob and reduce the voltage to the motor instead of switching off the power.

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Re: Battery Buggy B

Postby shrewdPanther46 » May 4th, 2018, 7:20 am

Clever idea, I have never tried it. The issue I see with that, is when you are gradually introducing your braking force, its not going to actually help you, it will hurt you at the very end of the run. Think about it: your car will be going faster right before the final mechanical stopper engages than if you immediately cut power, which kinda defeats the purpose.
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Re: Battery Buggy B

Postby Akshu007 » May 4th, 2018, 9:07 am

The Potentiometer will gradually reduce the electrical Power, and should only slightly increase the braking force. Since this is a slide Potentiometer, the arm of the wingnut can be positioned to hit the Potentiometer when the vehicle speed needs to be reduced.
https://www.amazon.com/BOURNS-PTA6043-2015DPB103-POTENTIOMETER-SLIDE-10KOHM/dp/B00L9YE2ZA/

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Re: Battery Buggy B

Postby M017 » May 8th, 2018, 6:48 pm

I've been trying to work out a formula for my car. I found the degrees of turning per cm, and multiplied it by the cm that I want then divide by 360, I used the degrees/cm based off of a .2mm off 12m run, but if I use that for a 9m run, it comes up 45cm short? Any ideas why
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