DIY Semi Auto Grinder Builds Itself (Sort Of)

[JSK-koubou] is no stranger to making tools to improve their work, and this latest video is yet another in a long list of such builds, just checkout their YT channel to see the many other examples. The tool being highlighted this time is a semi-automatic grinder (Video, embedded below) which could be very handy in many situations.

Many of us struggle a little to get straight cuts with an angle grinder, especially with softer materials, as it is sometimes hard to get a good ‘feel’ of how the cut is proceeding. Once the cut is started, thin blades will tend to ‘track’ in the slot, so if it starts off a little bit, the whole cut will be off. Most annoying. Anything to help keep things straight and square would help a lot, with the extra feature of a motorized drive enabling a constant cut rate, and presumably giving an increase in the cut quality.

Using the part completed rig to cut its own leadscrew

Since operation is hands-off, you could set it up, and leave it to do its thing, whilst you step aside, away from flying sparks, noise and the remote possibility of getting a splintered blade in your face, should the unthinkable happen. All good things.

The detailed build video shows what looks like a pretty solid construction, there are plans available on the accompanying website, but they do request a small donation of ¥1000 (less than $10 USD) to download them. Given the usefulness of the tool, this seems like a small price to pay. We quite liked some sections of the build video, where the tool is used to cut its own components, as it is built-up sequentially. Clever stuff! Another interesting technique to see was the use of a flame-heated (Stanley) knife blade as a drive belt end-jointer. Somewhat tough on the blade, but it’s a consumable item and gets the job done, so that’s good enough for us!

Parts wise, there’s nothing special at all here, with most easily sourced via the usual mechanical suppliers, but we reckon you’d be able to find most of it on eBay as well. We think this is exactly the sort of build that would work well in your local Makerspace, so perhaps give that a thought?

Bored with manually cutting off? Need an overkill solution for a mundane job? How about an Automatic Cut-Off Saw? If you need some defense against the mighty angle grinder, then perhaps Proteus is just the ticket?

Thanks [Keith] for the tip!

12 thoughts on “DIY Semi Auto Grinder Builds Itself (Sort Of)

    1. the fact it works AT ALL is a paradigm shift in international communication for tinkerers. if I can figure out the basics of how to compile a Ruby based keyboard firmware using badly translated Japanese instructions and inferences, using google transale then this mechanical doohdad is a doddle. I’m also not a coder, but can infer enough to sellotape together everyone elses work!

  1. So, Reverse engineer your own using the extensive images they have. Looks simple enough and something a dedicated tinkerer would take only a couple of weekends to produce. Or, chip in 10 bux as a thankyou for their research and spend a single weekend producing it….either is viable

  2. you could set it up, and leave it to do its thing, whilst you
    step aside, away from flying sparks

    I’d make sure I’d watch those flying Sparks at all times, and have the fire extinguisher somewhere in the room, though.

  3. Don’t understand what the big deal is here. You can build it yourself if you want to, they showed you how it worked. If you want the plans, about $10 seems reasonable to me. Lots of open source builds also can provide hardware kits, build guides, etc for additional cost. Do you want everyone to provide their time and effort to you for free? Do you think it costs nothing to provide download servers and bandwidth?

    HAD also has lots of articles about things you have to buy like 3D printers, single board computers, computers, etc.

  4. Another idea for anyone interested…

    I found a radial arm saw at the scrapyard (burned out motor). After removing the motor, I made a mount for my angle grinder on the legt side (so that sparks/debris shoot away from me). Just used some shims to true it up, and now I have a way to cut straight, including angled cuts and mitered cuts with adjustable height. Works best to start at the top, and lower slightly at each pass.

  5. Another “invention” looking for a problem to solve. Wrong on a few levels. Rigidity 4/10, jank factor 7/10, cutting in the wrong direction, and is that threaded rod and an o-ring drive?

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