Piccolo CNC Part Two: Assembling the gears and chasis

Hi fellow Piccolo builders!

@Andrew_Hendriks @3bien @lukecyca @jarrett @mkobie @jon_slaco @Janet @sIGNgUY @johnbiehler @jon @funvill @packetbob @RandyNW @johnbiehler @interlock

Tonight @jon and I took a crack at test fitting a Piccolo. Here’s how it went down:

We cut the chasis/body using 3mm plywood we found (checked carefully for no name), and the 3 mm acrylic provided by @RandyNW was used for the gears and tool holder.

Assembly in progress. We didn’t have the special low-profile M3 nuts and bolts, so we just loosely put it together. @Jarrett has mentioned making a bulk order from Fastenall I believe, can he confirm?

Final fit.

Experience report:

“Makes you appreciate how clear LEGO instructions are.”

The fit of acrylic and plywood seems good. We used my board, and it looks like there was a height problem on one of the capacitors such that the y axis gear strikes it. Plan to fix this using the GSM 90 card spacers that we laser cut.

Don’t forget the X3 component (looks like a capital I or bow tie) in step 6, it’s easy to overlook.

During a test run of the spiral demo program, if the motors stall they appear to draw too much current for a regular USB PC plug. This causes the voltage to drop too low for the Arduino and it will shut down. This can be solved by using a powered USB hub, but you still need to solve the motor stalling problem. In this case it looks like the motor was in the wrong position and hit the end of the track.

Summary

I’d like to suggest that people hold off on cutting their own until we can verify that the test Piccolo build is stable. To do that I need to get the proper nuts and bolts and assemble it, then let it run itself ragged.

The files for the chasis and the gears/tool holder are all now on the laser cutter computer. I’ll ask @jon to post the exact filenames so people can find them.

All the materials (the plywood and the acrylic) are in the materials storage, labelled “Piccolo.”

The GSM 90 card spacers (provided by @funvill) are in the locker with my name.

Special thanks to the laser cutter committee (@rsim, @garthomite, @jon) for getting the laser cutter operational!

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Sweet! Thanks for keeping this rolling and for verifying the test build!!!

I think @Jarrett was going to try pacific fastners, I can pick up an order in Blaine from Fastnell if necessary.

BTW There are two PCB thicknesses I believe, the ones I ordered are 1.6mm, the ones @RandyNW ordered are 1.2mm (the default from dirtypcbs).

Great work, guys! I had a feeling the Piccolo instructions were a little fuzzy but with a few adjustments this will be a very cool project.

Brilliant teamwork, too, I must say …

Other notes -

  • Servo alignment is a pain, and the method in the instructions was problematic. I’d suggest having an arduino around to center your servos, and align to the midpoint, instead of the end.
  • Getting the servos positioned at the correct depth is a challenge. There was an additional piece on the Z axis that doesn’t appear in the assembly instructions, but helps with this.

So, to clarify:

What’s a good local source for the nuts and bolts?

M3 10mm low profile cap screws (8)
M3 16mm low profile cap screws (3)
M3 10mm cap screws (2)
M3 22mm cap screws (4)
M3 low profile nuts (17)

The catch here is that we need low-profile metric hardware, which is very hard to find.

I checked out Pacific Fasteners yesterday, but they close at 4:30.

I’ll try and make it out sooner in the next couple days.

Fastenal doesn’t have any appropriate stock locally, and their prices aren’t great. We’d be better off going with McMaster Carr, if we can swing it.

This is great news!

I’m left with two questions:

  • Are we still group buying the fasteners?
  • Ditto for the laser cut parts? Or, do we need to schedule some laser time with a trained member to get everything cut?
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@Jarrett I work up the road, I could head there at lunchtime today if you haven’t already been.

Sure! That would be great.

Ok, I’ve printed the specs from accugroup, will just try to get two sets for a test run.

We’re trying to.

This is great! If I can use one of those sets, I should be able to stop by the space and fully assemble the test print.

That would let us see how the whole kit goes together before building them all.

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Wasn’t a total waste of time, they’re a the top of a killer hill so I got a good workout on my bike but no parts. “Sorry nothing that small and I wouldn’t know where to send you”.

I can pickup a small order from McMaster in Blaine but it won’t cover everyone (needs to be sub $100). Can someone perhaps find all the parts and get a list together here?

eg. McMaster-Carr the head on these is only 1.65mm high but the diameter of the head might be too big.

There are both low profile and normal 10mm bolts in the BOM, suggest just buying low profile to make the quantity more attractive - will this work in the model?

Perhaps these are right? McMaster-Carr

Here’s the BOM from Piccolo:

Hardware
Part#Sources and NotesCost Each (USD)Cost Total (USD)Corona DS-929MG
digital servo3Hobby King
http://www.hobbyking.com/hobbyking/store/__16342__Corona_Digital_Servo_2_2kg_12_5g_11sec.html
7.1521.45M3 10mm low profile cap screws8Accuscrews
http://www.accuscrews.co.uk/low-head-cap-screws/8723-SSCL-M3-10-A2.html (min
order 100pcs)0.050.40M3 16mm low profile cap screws3Accuscrews
http://www.accuscrews.co.uk/low-head-cap-screws/8726-SSCL-M3-16-A2.html (min
order 100pcs)0.050.15M3 10mm cap screws2Accuscrews
http://www.accuscrews.co.uk/cap-head-screws/3819-SSCF-M3-10-A2.html (min
order 100pcs)0.050.10M3 22mm cap screws4Accuscrews
http://www.accuscrews.co.uk/cap-head-screws/2803-SSC-M3-22-A2.html (min
order 100pcs)0.080.32M3 low profile nuts17Accuscrews
http://www.accuscrews.co.uk/thin-hexagon-nuts/73054-HFN-M3-A2.html (min
order 100pcs)0.030.51
Please count me in for one order of the above.

Reposting:

So it should be under $100 for everyone.
One of the mechanical guys in my office said he gets M3 parts locally at Daiso, a Japanese dollar store in Richmond. Low-profile stuff is probably still out, though.

Duh.

Ok @wander @3bien @lukecyca @jarrett @mkobie @jon_slaco @Janet @sIGNgUY @johnbiehler @jon @funvill @packetbob @RandyNW @johnbiehler @interlock

Can we commit to splitting the $US70 plus shipping amongst us all? Should be about $CA5-7 each. I’ll order tonight if enough people are in.

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Sure. Someone will want to double-check my work, though.

I’m in…

I’m in too — thanks!