LR3 mod - Pen / Drag bit/knife mount and adaptor

V1E LowRider 3 mod - Pen / Drag bit (RDZ) mount and adaptor


Mod mounts Pen, Drag knife or (RDZ) Drag bit. Oversized holes for reusable zip ties. No screws/bolts needed. Leverages mount design features to increase rigidity.

Models on Printables and Github, discussion here.

Purpose / Problem

Created while trying to etch Specular Holograms, which require very shallow scratches. Was initially using a diamond drag bit in the router, but that puts too much pressure onto the stock, and ends up engraving/gouging too deep. So…

Looked around for existing mounts but couldn’t find one that supports reusable zip ties. Also, other mounts I stumbled onto were too high for the drag bit being used. Am looking for something rigid in XY, but has some flex in Z axis, want to make light contact.

Design goals/features

  • Holes for reusable zip ties. Made tight enough to hold zip ties when not in use. No need to burn time finding some.
  • Included 18mm dia, 3mm height cutout for drag knifes from V1E Shop (testing pending…)
  • Mount attaches to my Makita router in specific location that:
    1. Doesn’t block visibility of the bit where a gap in the dust shoes exists.
    2. Doesn’t block access to changing router bit (verify…)
  • Mount shape design leverages and hugs features on the LR3 Router mount, this helps increase rigidity. Design enables just one ziptie needed to fasten mount to the router.
  • 3.3mm Diameter hole on the adapter enables push to release/remove bit. Alternatively can use to mount something with M3 bolt.

Included .3mf with parts oriented ready for printing without support. Print depends on small bridging and couple of small 60deg overhangs.

See also:

Render showing various zip tie fastened mounts next to each other.

Future Improvements: (please ping if you remix and make better, cheers!)

  • Could be stiffer in XY. Maybe make triange/wedge with 2 edges coming off the router mount?
  • Could be looser in Z. Maybe make alternative model with thinner/narrower support arms.
  • Lost Z alignment ~25mins into an engraving session, bit seems to have been pushed up somehow, scratches were noticeably lighter. So, could probably be stiffer and/or less play with higher tolerances. Not sure, mentioning as something to look out for.
  • Adjustable Z alignment, manual, or something smart like pressure sensitive/maintaining device?

Related Parts



Nice! Are you making your own SW to create the hologram files/gcode?

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Yeah, but…

Couple weeks ago, saw Steve Mould’s diy hologram video containing inspiring content on Specular Holograms. Dug around and found Mike Miller’s scratchhologram project, shared link to his project and other info stumbled across in the drag-knife-and-laser-etched-specular-holograms topic where several folks were also curious about Specular Holograms.

Started on a quest to replicate results using a CNC. Mike’s app has most of what was needed, the code was painfully slow with some quirks, but a great starting point. I could not have created something from scratch this quickly. Would be nice to package into something anyone could use. Added bunch of features, load .STL, export .SVGs, profile/contour detection, face merging/simplifying, Dark mode of course, and other stuff… Was exporting GCODE at one point, but removed because I want folks to make (and be responsible…) for their toolpaths, for now anyway.

Original App :

Latest App after much hackery :

Shared video clip, details and files over at Drag knife✒️ and Laser🔫 Etched (Specular) Holograms - #58 by azab2c

The Hologram results are visible, providing lighting conditions are precisely setup… Has been fun, plus I have a generic .STL to .SVG convertor app now. Plus this custom drag bit, and a bit more knowledge on misc topics encountered during this project. Much time has been spent on this…



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Noticing less than ideal XY flex. Notice how ends of the arcs are kinked/impacted, only visible when viewed up close. Sharing incase someone’s mistakenly expecting the mount to be super rigid in XY.

Yes, all the pen holders and drag knife holders using that PLA spring leaf method can suffer from that. I’ve pondered on more rigid solution with real spring tension option. Need something almost like a mini version of my plasma torch holder, with spring added, or air pressure down force like I saw on (I think) the “Stuff Made Here” channel for sharpie on his plasma cutter.

Hi guys I am hiring anyone that help me achieve the recipe for producing and designing stuff on metal worh specular holographic cnc engraving anyone up for the challenge ?

Anyone found/using a stiffer drag knife mount? Was planning on modding this mount to be more rigid in X and Y. Flexure but never got around to it.

Think software seems to work, but the mount isn’t rigid enough. Laser setup doesn’t have this problem and seems to provide more detailed results.

Do you have a test pattern/model, nothing proprietary? If not, then I can share the V1E .STL model and resulting arc patterns if I didn’t already to see what results people get. Anyone want to CNC engrave a holographic Coasty?

Will share what results I’m getting in Alu and Acrylic. That’ll help you compare with results you’re already seeing.

Trying out more XY constrained v2 mount. Printed in this orientation…

Printed with PETG, requires printer to have decent bridging. Needed some cleanup and manually forced motion to free up, and wear in, the print in place spring.

Still testing, but shared v2 .STL, and Fusion files on github incase anyone wants to use, or extend…


Any time a CAD screenshot gets posted, I try to rotate it…every time.

Definitely getting better results with v2 mount more flex in Z, but rigid in XY. Modified v2 model to encase/constrain the print in place Z spring. Fits Makita and Kobalt router mounts…

Shared fusion 360 files on GitHub in case someone want to do a kinematic accessory remix :wink:


I was thinking about an adapter that fits into the router and for lateral stability and rigidity, that loads a spring-loaded drag bit/knife for dynamic pressure in the z-axis by using springs with various spring force ratings depending on your needs.

Not sure if that would get you where you need to go, but it was worth putting out there.

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