Dragknife musings. New here!

Hi! New here but have had the Shapeoko XXL for almost a year now and have dabbled in CNC stuff for a few years. We’re actually building an affordable fiber laser metal cutter from scratch right now!

I just wanted to share that I ordered a 3/8" Makita collet from Elaire corp and also a digital indicator with a protected plunger at the top. The idea is I can mount it in the router (unplugged) and sweep across the future Alca5 cast baseplate that will eventually be added.

We do dragknife cutting using a Donek D3 with costly material and having a good base is key (have had too much scrap). However, until all those upgrades are done, we are going to try our spring loaded Donek D3 idea today or tomorrow. :slight_smile:

Just yesterday we took the leveling feet off and placed the Shapeoko on a 1" thick EVA foam mat.

Some more helpful information: for non-basic shapes, we use the Fusion360 paid Dragknife plugin by Peter Böker. For basic shapes, we wrote a terminal script where you select the shape and dimensions and it automatically saves a gcode file without having to do any CAD or CAM work; it’s very fast! 98% of the shapes we cut use the terminal script.


Anyone else here do Dragknifing? Crickets

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I don’t but I have been eyeing the Donek knives for a while so I’m interested to hear about what your are cutting and see what the results look like

Could elaborate on that ? what solution has been working for you ?

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Hi Julien! We cut extremely high temperature flexible magnets; sort of like a fridge magnet on steroids, except used for 3D printers.

Currently we’ve had to have a sacrificial scrap layer underneath the layer to be cut due to issues with the middle sagging on the XXL, which is why we took some time to shore up the machine this week and are on an upgrade path now.

Here is a pic of a test cut we programmed manually this evening, yielding square corners. Previously we had rounded corners, but on one specific corner would overturn too far since the tip of the knife would dig in too low. Having the square corners now prevents the knife from doing that. Only disadvantage is slightly more scrap now since the cut extends beyond the shape’s bounds, but that’s ok since efficiency should be improved. :slight_smile: With this cut toolpath we created, the knife never leaves the material until it reaches back at its start point since the shape is basic enough.


Nice cut. How do you hold the stock onto the scrap layer & wasteboard ?

Photo #2 has a silver colored metal plate screwed to MDF base, so the magnet holds itself down. (Incredibly strong magnet material). There is no scrap layer anymore, that was previously without spring loaded modification.

Z zero is on top of metal, and then jog down 4mm and set Z zero again. This creates 4mm worth of preload based on the spring’s compression! :smiley:


This is also showing how we created the modified Dragknife. Shaft collar, spring, precision ground shoulder bolt, and two precision stainless bearings, since the original ones didn’t last long. Shaft collar lets you set spring pressure in addition to having it inserted into collet at same depth every time! Shoulder bolt is precisely undersized to slide up and down in the two bearings’ inner races.


The digital dial indicator came today. Unfortunately the plunger cap had a knurling on it that would’ve prevented it from being inserted into a collet, so I took the cap off and chucked it in a drill and used a file to remove the knurling :slight_smile:

It will slide into the collet great now!


Who needs a lathe when you’ve got a drill, a vice and and some old bearings :wink:

Where did you find a 3/8” makita collet from elaire? I’ve only seen the 3/8” direct from makita.

Just email them first. They will tell you to order a normal sized one (MRP-3150 specifically) and they will handle it when you email again to confirm the order with them.

They haven’t been good in replying to emails. My order still hasn’t shipped and no followup email after I sent the paypal order.

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That’s good to know!

Elaire just emailed and said it will ship out this week. They must be watching this forum :slight_smile:

Ha! On a Sunday nonetheless

I also picked up one of these. https://boringresearch.com/store/desktop-spindle-square/

The indicators it comes with are too big to fit underneath the router and a supplementary wasteboard though (hits Z axis hardware), so I ordered some mini indicators from Shars with the same 0.0005" resolution as what the spindle square came with. https://www.shars.com/250-dial-indicator-3

The owner is going to send a return box for the original indicators and refund the price of the indicators if these mini ones work out. :slight_smile:

The tool should come in useful for tramming drill presses and mills too I figure.

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Mini indicators just arrived :slight_smile: much better.


I see that trim guage is out of stock right now. The one I ordered earlier this year is here: https://www.amazon.com/Edge-Technology-Mini-Tram-System/dp/B01MCY6CLH

Also for anyone wanting to see the Donek D2 model in action here is a video.

I have a Vinyl cutter that will do some drag knife stuff on a VERY elementary level. So look forward to learning more on how this can be carried over to our Shapeokos!

If you have any questions about dragknifing, I’d be more than happy to help!

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I just look forward to learning what you can do with Dragknifing. To be quite honest I had to look up what it was :slight_smile: I posted the video in case any other folks were in the same boat as me. I have only done wood work with my Shapeoko.

Here is a link to the 1" thick EVA mat we put under the Shapeoko.


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