[MOC] Cutting steel with a Lego Angle grinder

[Marxpek]

Hey all,

it has been ages since i have been on EB, no particular reason, it just slipped my mind.. but yesterday a friend reminded me about EB, so here i am...with another silly video.

Being a metalworker, i tried to combine hobby and work. I set out to make a functional angle grinder that could cut steel.

It is pretty basic, 4 buwizz and 4 buggy motors drive a portalhub geared up 1:5, the hub holds a 3D-printed part with a M14 nut to hold the original metal chuck and abrasive disc, 

DO NOT TRY THIS AT HOME, it is seriously dangerous, i have seen discs shatter and explode, luckily not in the Lego version..

so that was my small reintroduction here, i will try to be more active again.

[Gray Gear]

This is very impressive and kind of stupid at the same time 

I mean why would you do this? But you showed you CAN cut metal using LEGO, and thats just a massive flex imo 

[Jurss]

First lego and also smart grinder.

[braker23]

You never cease to amaze me, great work. The possibilities with LEGO are endless, and you proved it once more :)

[howitzer]

That's really awesome! But stupid. But awesome!

It even sounds like a real angle grinder!

[Rudivdk]

Dude...

What can I say: seriously brilliant and seriously silly, I love it! Totally different from your speed record cars, but again you pushed the bricks to their max and raised the bar of what is possible with LEGO.

Last second of the video made my smile even bigger

[nerdsforprez]

Silly + brilliant = silliant.  

I dub this MOC "silliant"

[MajklSpajkl]

Heheh, good stuff! I wonder how do banana gears look after the procedure - are they fused with the metal powder?

[jorgeopesi]

This is my main tool and now I see it even on my hobby  .

[johnnym]

Oh man, you crazy scientist! My father would like that.

[Vectormatic]

Walking the line between brilliant and insane, love it!

While using the grinding disc i think it wobbled quite a lot though, i'd be more worried about the axle bending slightly and then going completely  rogue rather then the disc shattering.

 

(loved that you welded the fork back together by the way!)

[howitzer]

A bit off-topic, but hasn't the shattering disk problem have been solved already years ago with disks that are reinforce with fibers embedded into the disc material? I've never used an angle grinder disk that doesn't have reinforcing fibers nor have I ever had a disk completely shattering no matter how hard it's been abused, except the small Dremel disks still come without reinforcing (and thus are prone to shattering really easily). I use similar but reinforced ones for my jewelry work and never had any problems with those.

[nerdsforprez]

1 hour ago, howitzer said:

A bit off-topic, but hasn't the shattering disk problem have been solved already years ago with disks that are reinforce with fibers embedded into the disc material? I've never used an angle grinder disk that doesn't have reinforcing fibers nor have I ever had a disk completely shattering no matter how hard it's been abused, except the small Dremel disks still come without reinforcing (and thus are prone to shattering really easily). I use similar but reinforced ones for my jewelry work and never had any problems with those.

Not sure what you mean by years ago but I had one explode on me in the mid-2000's.  Scar right here that reminds me everyday with metal fragments still embedded in my arm....

[Marxpek]

heh, lots of response for such a simple build..

6 hours ago, Gray Gear said:

I mean why would you do this? But you showed you CAN cut metal using LEGO, and thats just a massive flex imo 

you awnsered it yourself, just too see if it can be done.

 

3 hours ago, MajklSpajkl said:

 I wonder how do banana gears look after the procedure - are they fused with the metal powder?

this is the worst of the "damage"  it kind of wipes right off, like you can see on the axleholders, but i barely used it besided what is shown in the video, to prevent damage.

2 hours ago, vectormatic said:

i think it wobbled quite a lot though, i'd be more worried about the axle bending slightly and then going completely  rogue rather then the disc shattering.

kind of true yes, but the disc assembly is also held by the portalhub and the 3D print, not just a single axle. but again: do not try this at home..

 

1 hour ago, howitzer said:

A bit off-topic, but hasn't the shattering disk problem have been solved already years ago with disks that are reinforce with fibers embedded into the disc material?

it has improved with this yes, but especially the thin cutting discs can shatter when they get jammed, become uneven or get sideways pressure/flexing, as a daily user of these discs i can confrim these can still shatter violently.. 10k rpm is no joke. I had to use wd40 to prevent melting the gears, axle and hub. as my 6k rpm card shooting machine learned me..

[howitzer]

1 hour ago, nerdsforprez said:

Not sure what you mean by years ago but I had one explode on me in the mid-2000's.  Scar right here that reminds me everyday with metal fragments still embedded in my arm....

 

1 hour ago, Marxpek said:

it has improved with this yes, but especially the thin cutting discs can shatter when they get jammed, become uneven or get sideways pressure/flexing, as a daily user of these discs i can confrim these can still shatter violently.. 10k rpm is no joke. I had to use wd40 to prevent melting the gears, axle and hub. as my 6k rpm card shooting machine learned me..

I haven't been a daily user but got my fair share during the eight years I studied various branches of metalworking. They can indeed break if flexed sideways but in my experience the breakage is only as deep as the cut the disk is in, and the fragments tend to be pretty small (and thus less harmful than larger fragments would be) if the disk is of the fiber reinforced type. No sudden catastrophic breakages from simply spinning the grinder. Of course wearing personal protective equipment is a must, otherwise even the small fragments can cause serious damage (not to mention sparks...)

[dr_spock]

Love the welding of the fork.  Now if LEGO sells LEGO branded cutting discs and flap wheel discs. 

 

[nicjasno]

Would love to see your gearing/gearbox and what bearings you used.

[amorti]

This is brilliant. A 500€+ angle grinder! 

[neonic]

On 12/16/2020 at 9:09 AM, Marxpek said:

here i am...with another silly video.

It's indeed a pretty silly, but also great too see  First I thought (when I read the title) 'How can you cutting steel ...'? Then I saw the movie. Making an angle grinder of Lego, never seen it. Looks great. Also funny to see you first cutting a spoon in two, then welding it together and put it back in the drawer. 

[JintaiZ]

Looks a bit crazy and weird, but then that's what makes it cool! 

[2GodBDGlory]

4 hours ago, neonic said:

Also funny to see you first cutting a spoon in two, then welding it together and put it back in the drawer. 

Yeah, that was the best part!

[SNIPE]

*ebays his regular grinder*

Don't need that anymore :)

[Brickend]

The most dangerous thing in this video is the state of the kitchen!

[Marxpek]

On 12/16/2020 at 5:29 PM, howitzer said:

No sudden catastrophic breakages from simply spinning the grinder. Of course wearing personal protective equipment is a must, otherwise even the small fragments can cause serious damage (not to mention sparks...)

I dont think this happens anymore indeed. And of course protection is a must..

16 hours ago, Brickend said:

The most dangerous thing in this video is the state of the kitchen!

LOL, yeah true.. that what i get for having kids.. and what can i say.. i am a builder not a cleaning lady :)

On 12/17/2020 at 8:39 AM, nicjasno said:

Would love to see your gearing/gearbox and what bearings you used.

 2x 40z gear between 2 buggy motors, those mesh with a single 8z gear, which axle goes through a portal hub and through the 3D print. So no bearings, but as mentioned before, i did use WD40 on the axle and the 8z gear and used it as short as possible to prevent parts melting and fusing together or worse.. come off..

[Newest_Tech320]

super cool