Repairing A Wounded Mantis

While it’s true that we didn’t specifically say making Hackaday staff exceedingly jealous of your good fortune would deduct points from your entry into our ongoing “Repairs You Can Print Contest”, we feel like [Sam Perry] really should have known better. During a recent dumpster dive he found an older, slightly damaged, but still ridiculously awesome Mantis stereo inspection microscope. Seriously, who’s throwing stuff like this away?

Rendered replacement mount in Fusion 360

Apparently, the microscope itself worked fine, and beyond some scratches and dings that accumulated over the years, the only serious issue was a completely shattered mount. Luckily he still had the pieces and could get a pretty good idea of what it was supposed to look like. After what we imagine was not an insignificant amount of time in Fusion 360, he was able to model and then print a replacement.

The replacement part was printed on a Tronxy P802M in PLA. Even at 0.3mm layer height, it still took over 10 hours to print such a large and complex component. A few standard nuts and bolts later, and he had a drop-in replacement for the original mount.

Whether it’s due to how big and heavy the Mantis is, or a slight miscalculation in his model, [Sam] does mention that the scope doesn’t sit perfectly level; he estimates it’s off by about 5 degrees.

We’re somewhat suspicious that mentioning an error of only 5 degrees is a stealth-brag on the same level as telling everyone you found a Mantis in the trash. But if [Sam] gives us the GPS coordinates of the dumpster in which people are throwing away high-end lab equipment, all will be forgiven.

There’s still plenty of time to get your entry into the “Repairs You Can Print” contest! The top twenty projects will receive $100 in Tindie store credit, and the top entries in the Student and Organization categories will each receive a Prusa i3 MK3 with the Quad Material upgrade kit: arguably one of the best 3D printers currently on the market. If you were considering going back to school, or finally leaving your basement and joining a hackerspace, now would definitely be the time.

20 thoughts on “Repairing A Wounded Mantis

    1. I agree, especially if you have a particularly hot day in the shop. Also, it can be quite brittle. ABS would be a better choice holding something heavy like this – at least you have a chance of catching it as it sags rather than watching it suddenly break and drop the Mantis onto the desk.

  1. Surprising something like that would get thrown out just for a broken mount. Pretty sure Vision Engineering could sell them a new one without problem.

    Also, damn I’m jealous. Nothing beats one of those Mantis scopes for ergonomics if you spend a lot of time staring down a stereo microscope.

    1. Its an older model. We cannibalize our older ones for parts when we can, but generally the same parts fails, so there is limited success in that approach. Otherwise, we had to purchase new ones.

  2. Seems to be a common failure point for the mantis, I’ve seen 3d printed replacements on a certain auction site.
    My mantis came as just the head, no stand at all. Eight cheap kart rod-ends, some 8mm steel bar and a small gas strut got the whole thing mounted to a bench upright, though the prototypes ends were 3d printed to check dimensions and useability.

    1. Not so much a common failure point as a common bit that the thieves don’t bother unscrewing from the desk when they break in and make off with the body. I’m not saying that yours was stolen, but I reckon that most sold without the stand were.

  3. I’ve done some 3D printed repairs, but I want at least the chance of winning a nice 3D printer. Can I enter as the Organization to educate myself, with a faculty and student body of Me, Myself, and I?

  4. Seems typical weak point. Ours here broke the same way. I cut and bent 2 pieces of sheet metal to u-shape and bolted them together. Then I used a longer bolt and a spacer on top as the pivot axis and that fix has worked since. The one-sided bracket is a weak point, it needs to hold at the top as well to avoid breaking.

    1. Yep… this is a well known problem for this series of mantis microscopes.
      The most annoying part of it all is that the manufacturer does not make/supply any spare parts. Considering the cost of the microscope, that is a major disappointment. We at work have 2 of these beauties, as we are very fond of them we were pretty sad when one broke to a point that it was unusable. Then we found out that spare parts were no longer available :(

      Fortunately… on thingiverse somebody else had already solved the problem:

      It took me 11 hours to print (used a 50% infill, just to make it extra strong) but it was all worth it. And the microscope is now working like a brand new one. A pretty expensive piece of equipment rescued by a few euros of plastic and a day of baby sitting… ehhmmm I mean 3D-printer sitting.

    2. I have a heavy duty stapler I fixed years ago, long before there was a thing called RepRap. The problem was the parts of the plastic inside the handle that pulled the plunger back up had partially broken.

      So what I did was marked on the outside where the inner protrusions were, then chain drilled a slot in both sides of the handle, followed by filing to straighten the edges.

      Replacing the protrusions was done by milling a piece of aluminum into an L shape. I cut that in half and stuck them to the outside of the handle with JB Weld, with one leg poking through to replicate the shape of the protrusions.

      Works just like original and it’s *never* going to break again. The stapler only cost 50 cents and I had the aluminum and JB weld on hand, along with the 12 Speed Drill/Mill.

  5. My Mantis scope had a different problem: no base. When I first got it, I thought no problem, but as we’ve all found out, Vision Engineering doesn’t even want to talk about these old scopes let alone supply parts for them. I thought I had lucked out when I saw ‘universal’ mounts for sale. $75 bucks later I find out there’s universal and then there’s universal…

    I bugged a few people who had an original Mantis for sale on eBay and got a few measurements. A few more measurements on my own and now I have my own. It’s not perfect, but it’s nearly free. I printed it in 300g of PLA at 80%.

    I also have a model for the objective turret gear that might come in handy

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