For anyone who is not pretty experienced in Fusion, that which is seemingly trivial can be seriously non-trivial! Been there, done that, got the t-shirt, and washed it til it’s unreadable. LOL
It took me a couple months before I figured out how to use sketches to create bodies, so I feel your pain…
Fortunately the several months that I spent trying to learn FreeCAD helped out a lot when trying to learn Fusion 360. A lot of the concepts are the same (or at least similar), but the workflow varies a bit (actually more than a bit).
Warning again: Don’t forget there is a belt that serves as a fancy strikethrough. Don’t ask me how I know. 
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Yeah, I thought about that, but I think it will look better in the larger size rather than trying to cram it under the belt. Maybe I’ll regret that decision once I see it built.
You can check how it looks with mine: Der Froschkönig - Lowrider 3 in Oldenburg, Germany - #73 by Tokoloshe
If I had known I would have made it smaller. 
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Yes, I see what you mean. I wonder if there is a clear belt for sale anywhere? 
Here’s roughly what the first one you showed would look like with the X belt across it.
Is the gantry real narrow? The image shows it roughly compared to the gantry done for Johnathan’s.
Yes, only 942 mm. I used 10 braces, as that’s what the future larger gantry will be using, and trying to include numbers of braces in the parameters was just a little too complicated for me at the moment.
Next version should be about 52-60”
Here’s a screen shot showing what the X belt would look like with the smaller logo like on Johnathan’s.
And here’s a DXF of that design.
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Well now that the Christmas madness has subsided a bit, it’s time to get back to the LR3 build again.
I did manage to make a bit of progress over the last few weeks…
First of all, I upgraded the flat-ish table from a single sheet of plywood to a 63" x 120" framed table top (see post 68 in Table Ideas for those just getting started - #68 by Bartman)
When I was at the lumber store picking out the 10’ 2x4s for the table build, I noticed a bunch of full sheets of 3/16" and 1/4" hardboard sitting at the bottom of a pile of used cardboard. I asked the yard attendant about them, and he told me that they were scrap, and I could take them for free if I wanted. SCORE! One was a bit nicked on a couple of edges, but they are perfect for test cuts, possibly for cutting out struts (I was planning on using aluminum, but hey, free!), and possibly even for use as the lower skin on a future torsion table.
Next up was to sort out the dust collection. I have a built-in vacuum system in my house, and the canister is located in my garage/workshop, with an auxiliary inlet and a 50’ hose already available. The only thing missing was how to connect it to the LR3, as the hose was several mm smaller than the stock V1E dust shoe. I looked around the forums and didn’t find exactly what I was looking for (or maybe I did, but just didn’t recognize it at the time), so I delved into Fusion 360 and figured out how to design and print my own. Confused about Vacuum Hose Sizes
When I was building the table. I needed to make some straight cuts in the plywood, and trying to manhandle it through my cheap-ass table saw by myself seemed pretty sketchy, so I bought a couple of 24"x96" pieces of 1/2" styrofoam to lay on the garage floor, and used a circular saw with a straight edge clamped as a guide. It worked great, so I thought that I could re-purpose the foam sheets as a temporary (ish) spoil board, at least until I get the full sheet version of the LR3 built. I used 1" decking screws through the hardboard and the foam to secure the work stock to the table.
So that is the table and LR3 pretty much all set up to make the first cuts.
I figured that the struts should be the first thing made on the machine, so I spent some time sorting out nesting and arranging the different strut versions into a single file that I could put into EstlCAM and create the toolpaths.
I tried using DeepNest to arrange all of the DXF files onto a single sheet, but it turns out that the text all had very tiny gaps that EstlCAM didn’t worry about, but that DeepNest did. So I ended up just importing the files into EstlCAM individually, and used the Move tools to line them up. (I later found a Fusion 360 Add On called Fill Gaps that will correct all of the errors so that DeepNest can use the files).
I’ve made an air cut with the resulting gcode file, and tweaked it a bit to increase the travel speeds and to reduce the Z Clearance between moves, which shaved the time down by about 35%.
Hopefully tomorrow I can post pictures of the cut out hardboard struts. Then everything needs to be packed away so that I can get the car into the garage for a much needed brake job.
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Hurray! The inaugural cut on my LR3 (Little Red version) is complete!
A couple of things I will keep in mind for the next cut:
- The cuts are quite fuzzy on the top. I used a 1/8" single flute upcut endmill, next time I will probably try a downcut mill for hardboard.
- I noticed partway through that the router was whining just a tiny bit. I checked and found that I forgot to set the speed setting to match what I had calculated using G-Wizard and set up in EstlCAM. It was set at the lowest mark (~10k), so I adjusted it to 2.5 (~15k) and the noise sounded better. Note to self - set the speed BEFORE starting the cut!
- For each individual part I had screwed the material to the spoil board on each corner, and with one or two screws in each middle (after cutting the screw holes and then pausing). Where I had only used one center screw, the material was lifting a bit. This probably won’t be such an issue when I use a downcut mill, but even so I need to fully secure the material, especially light and flexible stuff like thin hardboard.
That’s all for now, time to disassemble and store everything away so that I can get my garage back to do some car repairs.
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I’ve found that this cleans up nicely with a quick pass of 220 grit sandpaper by hand. Way easier than I expected.
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With a finishing pass and an extremely quick touch of sandpaper that goes right away. As you dial in your cuts it will get significantly less as well. Down cut bits are not much fun.
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That was with a finishing pass at 0.35mm and 2400 mm/min (initial pass 3.18mm and 1800 mm.min). It did leave it fairly fuzzy, but…
did clear up the fuzz from the outer edges and most of the top surface. There is still a bit left on the inner edges (text and holes), and getting into all of the nooks and crannies is a bit finicky.
I’m hoping so, although I’m not planning on too many more hardboard cuts in the future, mostly thick plywood and thin to medium (9 mm) aluminum. (Probably will use hardboard as test cuts for those).
I’m curious. Can you please elaborate?
Ryan can answer of course. I would just mention, they do the opposite of evacuating the chips out of the slot. They are pressing the chips into the slot.
Yes, I understand that chip evacuation is an issue with downcut. just didn’t think that it would be a huge issue with a total DOC of around 3mm. Am I mistaken about that?
Probably not mistaken. My experience with cutting hardboard was the same: fuzzies, sanded off. I think it’s what pretty much everyone gets with cutting hardboard. It’s got its own characteristics.
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