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Grabhole QR adapter for Rapido Technology V3 clamp

Creation's quality: 5.0/5 (1 vote)
Evaluation of members on the printability, utility, level of detail, etc.

3D model description

This ring is the original base for the stand-alone Grabhole adapter:

This QR adapter for the Rapido v3 anamorphic clamp ( allows for a secure connection of an anamorphic projection scope to a taking lens, while allowing a very fast taking-lens switch as well. Faster than Rapidos original solution, and much cheaper as well :) works with and without the FMJ as well, but for obvious reasons not compatible with the RMJ.
An additional goal with this QR clamp is to keep the optical chain as short as possible while maintaining security for every piece of glas. The only things seperating the scope and the taking lens is the wall-thickness of a stepper ring, so only around 1,4mm. This sounds like a lot, but no commercial clamp comes closer while maintaining a stable connection.

The locking-part goes onto the rear of the Rapido v3 clamp, while the ring that it locks onto is attached to the taking lens - the clamp-part is entirely printed, the part on the taking lens needs an additional step-up ring. The idea is that each taking lens has this dedicated ring always attached; as it's based on a stepper ring you can use normal lenscaps without any issues.

The taking lens connection of this version is fully compatible with the stand-alone variant linked above. Even though you need to buy a step-up ring seperately, each taking lens you want to equip will only cost a few bucks. Also, you can use a rear-cap when you scope is not attached to anything; something you can't even buy from Rapido.

Note: this QR adapter doesn't have the structural integrity to hold your complete scope, so only use with a proper support, e.g. the original Rapido beam or front support of for the Rapido FMJ.


One additional part are needed for this QR adapter

  • Step-up ring to 77mm (the common cheap ones; works up to 72-77mm)
  • some drops of glue (optional)


The bare minimum to make this work consists of three parts you need to print. An indepth description of all parts can be found below.
To get all tolerances perfect, you should print all parts at 0,1mm layer height.

  • TK_ring (variants)
  • CL_Ring
  • GrabLocker

In theory, none of the parts is in the path of light but I'd still recommend printing in black for an overall nicer look; I like to set an accent with a different coloured GrabLocker :)


Two parts needs some additional sanding: the GrabLocker and CL_Ring.
GrabLocker needs to be sanding on its insides, the grooves as well as the general wall area. CL_Ring needs to be sanded on its outside, make sure to not damage the chamfer.
I use a rough 80 to 120 grit for the initial sanding, then something fine like 400 to make it smooth.


Sandwich GrabLocker between CL_Ring and your Rapido clamp, the dots on it facing in the direction of the camera. If you have issues screwing on CL_Ring, you can try to gently and evenly push it "onto" the threads and then tighten it with a lens wrench (or your thumbs); make sure that GrabLocker can be rotated freely, if this is not possible you should disassemble it again to sand the parts a bit more.

Now take TK_ring and push it from behind onto a 77mm stepper ring; the markings on them should face the camera-side. In the long run, I'd suggest to glue these parts together as depending on your stepper rings it might be loose or become loose over time (I exclusively buy stepper rings from VHBW on

You can make your life a little easier by painting the dots on the GrabLocker as well as TK_ring, e.g. with a Sharpie; I use Molotow acrylic markers.


It's pretty safe-explanatory, but what gives :)
Get your camera and scope on rails. Push the scope towards the taking lens, align the dots of the GrabLocker and TK_ring and push them into each other. Rotate the GrabLocker clockwise to lock scope and taking lens together, then lock your front support to the rails.
To change the taking lens, turn the GrabLocker counter-clockwise, push the scope away, switch lenses, push it back, lock and load :)


Follwing is a detailed description for all the parts provided

  • GrabLocker This integral part locks the scope to the taking lens; I like to have print it in an accent colour :)
  • CL_Ring This ring locks the GrabLocker to the Rapido v3 clamp
  • TK_ring This ring is what GrabLocker locks onto. It comes in two variants, with and without window. The window is there so you can still read the original markings on your stepper ring to be able to read its source-size on the camera-side. I found this very handy so far, but if you mind you can use the version without a window.
  • TK_Cap_full Combined with a windowless TK_ring, this part can be used to make a rear-cap that attaches to this QR clamp for when you don't have it attached to a camera. Needs to be glued - logo and markings on TK_window point in the same direction.
  • TK_Cap_52 In case you don't trust an all-printed cap, you can use this part alongside a windowless TK_ring and a 52-77mm to create a rear-cap that attaches to this QR clamp when you don't have it attached to a camera.

3D printer file information

  • 3D design format: STL Folder details Close
    • CL_Ring_v05.stl
    • GrabLocker_v03.stl
    • TK_Cap_52.stl
    • TK_Cap_full.stl
    • TK_Ring.stl
    • TK_Ring_window.stl

    Learn more about the formats

  • Last update: 2020/10/16 at 19:02
  • Publication date: 2020/10/09 at 22:51





b | de

I try to create things that make my life easier. Sometimes, I try to make the life of others easier.
It's simple stuff, but it usually works

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