Another DIY CNC router, part 5 (laser cut plates lookover, test cuts with MDF mockup)

0:00 Laser cut parts lookover
8:48 Used 6mm plate stock
13:36 Surfacing with MDF mockup
14:44 Test cuts in aluminium with MDF mockup

I clamped the X rails to the bench temporarily to try some cuts. It's going well so far, but seriously needs tramming. Not sure if I can be bothered :)

[ludwigbre]

Great progress :)
For the problem with the 6mm holes and M5 screws you could also use Helicoil inserts.

[kraklakvakve]

If the jigsaw blade is just clogged, maybe you can clean it with NaOH

[robmckennie]

Flashbacks to my time operating a couple of big lasers here in hawkes bay! Of course I can't speak to the quality of the service you're using, but I would say typically, in softer materials like aluminium or mild steel, tapping a laser cut hole in no issue. In fact, we even offered tapping as an extra service

[EnglishTurbines]

Aluminium is notoriously difficult to cut with a laser, as you've discovered...plus the heat build up and subsequent distortion of rolled plate...🤔😳🇬🇧

[jeffbluejets]

Lubrication or rather lack you're after cheapass, you can go mineral turps, if you want the best, especially if tapping holes and you don't want to end up with broken tap, use aluminium tap magic for cutting, drilling and tapping. You'll end up with a much closer tolerence finish.
We used to use a dry lube which came in a cartridge similar to a grease gun cartridge where one would dip the end of the jigsaw balde, drill or whatever into the dry wax like lube.As the contents diminished, one would simply tear off a section of the outer cardboard tube.
Haven't seen it around for many years though.
The aircraft grade aluminium I use here in small scrap offcuts, cuts, drills and machines more like fibreglass, whereas the everyday aluminium is daggy doughy and a real bugger to work with.
Only approach is lube, lube, and lube some more.
Any ridges will be due to the head being out of line.
Milling machine I have here with a dovetail z axis took near 4 hours to properly aline at zero degrees and then pinned at that. Reason being it has ability to be set on an angle and if I ever move it, I don't want to have to go through the same drawnout process.

[PiefacePete]

The roughness on one side of the adaptive clearing cut (19:00) will be from lack of rigidity in the MDF machine. The cuts on the near side are (by coincidence) trammed about right, while the far side is out because the cutting forces are in the opposite direction. You can pretty much guarantee this will disappear in the final build.

[PiefacePete]

Man... this thing is going to be BULLETPROOF! Sorry 'bout that, but it had to be said. :o)
You've got to be chuffed with the way it is turning out! I couldn't quite work out if the aluminium test cuts were in the 6mm "bulletproof" sheet; if they were, you have scored a win with that purchase.

[ddegn]

At 8:00 you mention you should have tapped the holes. Can use one of those those tread repair kits to add threads to your oversized hole?
These are called thread inserts or helical inserts. You can get 100 for $93 at Grainger. I think they're available from a lot of other places as well.
Thanks for sharing your progress with us. It's always fun to follow along with your projects.

[jotham]

Better to use zinc plated bolts with aluminium. Stainless will "gal" and binds super easily. Crazy easily, also creates a galvanic voltage differential leads to accelerated corrosion.

[samuelt]

Milling might be unpleasant in that second hand material because it is so soft, it might smear and clog endmills instead of toss chips away.
Edit: Didn't wait long enought before commenting...

[vizionthing]

How do you make aluminium bullet resistant just print bullet resistant all over it. I'm betting that's just regular aluminium that cost a premium to the government.

[robmckennie]

If you're brave, a regular circular saw will happily cut aluminium, I've even cut scrap aluminium castings with my skilsaw at a depth of an inch or so. You might try a coarser blade for your jigsaw, you should have no problems cutting aluminium much faster as long as you can clear the swarf, so big teeth are helpful there

[PiefacePete]

Is it worth using the machine as it is to remove the extra 1.5mm from the bottom edges of the gantry plate? (3:30 and 4:50) It would only be a straight cut, so with caution and conservative settings, you should get a good outcome. Maybe try it first on the angle plates? (4:20)
I just watched this for the third time in a row! I am probably in trouble with "She who must be obeyed"! Ahh well. :o)

[trt]

Nice and the machine is not even finished O.O

[jeffbluejets]

Laser appears not the ideal for parts which rely on cut sides to fit. Holes appear to have been started at the edge whereas a centre start would eliminate the blow out.
Overall I'd be more inclined to have the parts milled on cnc.

[rjung_ch]

Is the bend due to the heat from the laser cut or am I totally off with that idea? That is quite bent indeed.

[pete]

Could I ask where you got the laser cutting done?