Drag Knifes and Info About Them

In my search for a custom drag knife to use on my router, I was coming up pretty short on a lot of info that I wanted. I think a collective knowledge dump, and discussion would be very productive.
I’ve spent the last week doing an abundance of research and development. The options that were available to buy were sparse and expensive. Those included the SST (Stupid Simple Tools), Dog River Tools, and the most popular and expensive, Donek Tools.

The DIY options included some … interesting ones on sites like Thingiverse as well as the one I took inspiration from on here. That design is from Grunblau.com if you want to buy those.

After seeing those I started designing


Then decided I didn’t love the blade-holding portion and redesigned it. (scribbled over it to protect my design)

I thought I liked this one, but after cutting it out, I didn’t like how heavy the “flag” side was.
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I had also recently learned about topology optimization and wanted to incorporate that but I don’t like Fusion360.
Here is my sad attempt at that. At the same time, I calculated the weight on both sides of the rotation axis. I did not do radial weight because that was too much work.
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I am currently working on cutting out the bearing holding portion. Another component that I needed was a 1/4" shank that I found here.

On the software side of things, Vcarve pro has a gadget for a drag knife. I think it’s pre-downloaded nowadays.

I will try to update the forum as soon as I finish this, but it will most likely get posted here first.

Lastly here is a speeds and feeds calculator for metals and I will post the design on my Etsy once everything is finished.

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I have the carbide3d knife. Works a treat on thin material.

I have a silhouette cameo 4 for vinyl and very thin stuff but was tasked to make a cutter for gasket material.

I experienced too much deflection for my liking in the first completed personal version. In the meantime, for my project needs, I ordered a Dog River Tools drag knife and I will continue working on a personal version.