Skadis Hook for Heat-Set Inserts, M2.5 3D Printer File Image 1

Skadis Hook for Heat-Set Inserts, M2.5 3D Printer File Image 2

Skadis Hook for Heat-Set Inserts, M2.5 3D Printer File Image 3

Skadis Hook for Heat-Set Inserts, M2.5 3D Printer File Image 4

Skadis Hook for Heat-Set Inserts, M2.5 3D Printer File Thumbnail 1

Skadis Hook for Heat-Set Inserts, M2.5 3D Printer File Thumbnail 2

Skadis Hook for Heat-Set Inserts, M2.5

fivesixzero

October 3, 2022

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Description

NOTE: This is a part to be used with other Skadis mounting projects and doesn't do much on its own.

This is a simple hook for mounting things to Skadis pegboards. These hooks use M2.5 screws, which can screw into M2.5 heat-set inserts. The screws provide a very reliable interface which can take a decent amount of weight and can allow for easy rearrangement without having to worry about snapping off plastic protrusions.

The entire hook and the M2.5 screw fit through the Skadis peg board slots with just enough clearance to provide a solid hooking surface for the back side. I had originally planned to use more ubuqituous M3 screws but having a screw head smaller than 5mm was a critical requirement, which was difficult to find with M3 screws. M2.5 screws worked perfectly though.

Benefits

More flexible positioning of mounted objects
- This can be achieved by providing a grid of “sockets” on the back of a model (see image below)
Provides reliable mount hook by higher putting loads on metal parts
- This is a key point for anyone that's used printed hooks on Skadis boardsm especially if they've tried rearranging their board a few times.
Allows for easier part design/print by removing the need for awkward hook overhangs or slanted printing angles
- There are a lot of great designs out there that work great with “print-on” hooks, but for larger “holder" or “organizer” type designs it can be quite difficult to design a printable, reliable model.

Examples

Squirt Bottle Holder

Required Hardware

M2.5 screws with a 5mm or smaller diameter head are required to make these hooks work. I originally intended to use more ubiquitous M3 screws but it was hard to find readily available screws with a head smaller than 5mm, which is the upper limit due to the width of the Skadis sockets being 5mm. Inexpensive M2.5 screws with this (or smaller) diameter heads are plentiful though.

Also, the object being mounted on the Skadis, in turn, requires some sockets in it to install M2.5 heat-set inserts at the appropriate (20mm x 20mm) spacing. More on that in the “project usage suggetsions” section below.

The ideal length of the mounting screw will depend on the type of insert you're using. If the screw is too short it won't provide a solid mount and if its too long it can dig into the socket, which creates its own problems.

For 4mm depth inserts I've had the most success with 8mm screws and for the deeper, 5.9mm inserts 10mm screws have worked best.

Although its possible to use nylon/plastic M2.5 screws to attach these I recommend using metal screws. The screw itself will be bearing most of the mechanical load during mounting/unmounting and while at rest and some nylon screws may shear if they're handled roughly.

Suggested screws:

McMaster Carr 92000A105 (8mm, $4.74, 100 pcs)
McMaster Carr 92000A106 (10mm, $5.13, 100 pcs)

Suggested heat set inserts:

CNC Kitchen “M2.5 Standard” (ø 4.6mm, depth 4.0mm)
- Prusa Eshop ($11.99, 100 pcs)
- CNC Kitchen Store (€9.99, 100 pcs)
McMaster Carr 94459A439 (ø 4.1mm, depth 5.9mm, $9.50, 25 pcs)

Heat Set Insert Suggestions

If you've never used heat-set inserts before I recommend checking out Stefan's execllent CNC Kitchen videos and blog posts on them, which helped me out a lot. This article is a good start: TIPS & TRICKS FOR HEAT-SET INSERTS USED IN 3D PRINTING

For installing the inserts all you'll need is a cheap soldering iron that can take T18 and/or M900 tips and the apporpriate tips. For my bench I picked up a cheap $9 iron from Amazon just for this purpose and it works pretty great.

I hear a “drill press” type setup can be helpful if you're really anxious about getting perfectly vertical inserts. That said, I've added hundreds of inserts to my projects without one and they work just fine. Just remeber not to use much pressure - just wait for the insert to melt the surrounding plastic and let it sink in on its own.

For iron tips, I've been using this kit from CNC Kitchen and it works really well: CNC Kitchen Insert Tips.

Printing Suggestions

I've only printed these on FFF/FDM printers using PETG, but they should work fine in PLA or even printed on SLA printers using various resins. If you print these in SLA or with other filaments, please post a make or a comment with details on how it worked out for you. :)

For printing on my Prusa MINI+ I found the best results at 0.20mm with 7-8 perimeters, which eliminates the need for infill. Supports are required to allow for the overhang and I've had success printing both “screw hole down” and “peg leg down” orientations, although I've come to prefer the “screw hole down” orientation over time. I've also found using the “classic” periminter generator (instead of the newer Arachne generator) provides more deterministic, more symmetrical perimeters,

Although I haven't tested it yet, this shouldn't have much effect on the quality of the final print, but I've stuck to the “classic” generator since that worked fine for the dozens of hooks I've printed already.

I usually print 8-24 at a time so that I have plenty on hand for mounting future projects. Each hook usually takes 6-8 minutes to print.

Project Usage Suggestions

It should be relatively easy to remix any existing "Skadis holder" or “Skadis mount” model to replace printable hooks with heat set insert sockets at appropriate positions. Its even eaiser to build a project around, largely since the use of heat set inserts allows for more freedom in printability.

If you're using Fusion 360, I recommend importing a Skaids pegboard model into the project then using that to visualize how the finished product will look when mounted with various positions.

For my own Skadis holder projects I use Skadis pegboard models that I've created with sketches that have 4.4mm cirlces at 20mm spacing for easy socket extrusion. This file is available in the “Files” section - “Skadis (Short, Small Width) v6.f3d”. The “insert holes” sketch can easily be modified to match the diameter you prefer by modifying one parameter (d78). I tend to just create a grid of holes across the “mount surface” of the model, if possible, to allow for the most flexible mounting options.

As with any heat set insert project, its a good idea to test tolerances with your printer and the inserts you're using to make sure the hole diameters and depths work for you. In my case, using a stock Prusa MINI+ printing Prusament PETG, a diameter of 4.4mm and a depth of 4.4-5mm socket extrusion depth work well with the CNC Kitchen M2.5 inserts mentioned above (4.6mm diameter, 4mm depth). If you're using the longer, narrower McMaster Carr inserts then I'd probably start at 3.9mm diameter and 6.3mm depth sockets.

If you use these hooks in your project, I'd appreciate a link-back to this page or adding it as a “remix" of this to make it easy for folks to find the latest version of the original.