Drag Knife for cutting vinyl

I’m COMPLETELY new to the forums and I hope I have this question in the right spot.

I’m in the process of building my MPCNC and a thought struck me.

My job is as a graphic designer who creates signage, including cut vinyl lettering/logos as well as printing using a large-format printer.

Has anyone used the MPCNC with a “drag knife”? (a drag knife is a teeny, tiny knife that is pulled across the material (you may have heard of a Cricut?) cutting shapes/lettering out of it, similar to simply plotting. The difference is that pressure needs to be PRECISELY controlled and there is a very slight “offset” from center, of the castor action of the blade that should be precisely accounted for and adjusted.

Thanks for any info.



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Thanks, Barry. That’s useful.

However, I would need pressure control. For instance, the ability to dial in 110grams for one brand of vinyl and 140grams for another. This means that over a large area there would be consistency without cutting all of the way through the backer paper etc.

Plus, the “offset”… the caster distance from the center pivoting point of the tool to the actual tip of the blade, is important when cutting fine detail.

All of this may be too much to ask and is certainly beyond MY capabilities.

This is an interesting start though. Thanks again.

The knife we use has an adjustable tip to dial in instead of down force, as for the tip offset if you need anything beyond a lead in and lead out that is all software based and I have no idea if any of them output any kind of usable Gcode. My vinyl cutter outputs an odd file type but I have never bothered to open the file to check.

For the most part beyond a lead in tip offset is only noticeable on sharp corners (I believe my blades are a0.2mm offset). Compared to a vinyl cutter this head is massive, so that means slow. It will do a wonderful job in a pinch but if you need lots of cutting a dedicated machine is half the price of decent software. Sort of the idea of the machines I make, it can do everything but I am not trying to kill dedicated machines.

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If you search Thingiverse.com for Drag knife MPCNC you will get some other results as well.

The answer is yes you can attach several different types of knives and blades to an MPCNC. As for the ability to control the pressure. As far as I know the only thing you can really do is make sure you get the Z height set right first then use the blade pressure setting found of some types of blades. My wife’s Silhouette machine comes with blades with pressure settings 1 - 7 I think. I assume that if you attach these blades to your machine and can make sure you are at the correct height that these pressure settings will work the same way.

Or I could be totally wrong. That has been known to happen…

once or twice…

a day.

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I use one on mine. There’s a post in the forum somewhere about my experiences.

My wife got a cricut for Christmas. The MPCNC does a great job, but she needed something easier for her to use. Plus it keeps us from sharing my MPCNC.

I’ve done a few vinyl decals and stuff and a few custom masks for painting things.

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Here’s a shameless video plug:



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Re massive head…
Ahhhhh yes! I didn’t think about that part. That kind of negates doing a lot of tiny stuff and so also negates the issue of offset. (tiny stuff requiring more precision)
Good point!
Thanks Ryan!
By the way, this project of building the MPCNC and my other projects involving learning Arduino etc. have all been very helpful in resolving some depression. I used to be a tinkerer when I was a young man. This is good! :slight_smile:

The sharing of MPCNC is hard! LOL But the family that CNC’s together… :wink:

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Once a tinkerer, always a tinkerer. And it KEEPS us young…so there’s no such thing as “used to be a young man”. It does however also make us pull our hair out…which maybe gives the impression we’re not as young as our tinkering keeps us.

I too am from the graphic designer gene pool and am really loving the act of being part of the production world with the MPCNC - granted I’m now “producing” in wood and stuff but still. My Illustrator skills have set me in good stead with things like ESTLCam.

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Harbor Freight sells a pack of dental type picks for about $5 that make excellent vinyl weeding tools. Just, FYI. :slight_smile:

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Thanks for replying and I appreciate it.

However, it is actually my job and have all the tools. :slight_smile: In fact beyond work, I have a proper vinyl cutter at home as well.

This is more an exercise in… well… I’m not sure what this is an exercise in. :wink: An academic exercise I suppose. hehe


Well in that case then go crazy!!! Build the MPCNC and throw a laser on it! Melt that vinyl and release the toxic fumes! … I mean … uh… be responsible… and safe… and stuff.

No seriously. If you want to build the machine to scratch that tinker like itch. Do it. You will find uses for it. Even if you have to make them up. And you will have fun.

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It’s a gateway tinker though…you’ve been warned! Very soon my wife will experience the joys of discovering I have cut the middle out of our dining room table…

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“Gateway tinker”! HA! I LOVE IT!
I’ve had to deal with some health issues these past few years and I decided that I needed to MOVE more than sit down and BUILD rather than JUST design on the screen. I’m doing an Arduino course too.
Havin’ fun!!! :slight_smile:
Thanks again!

The laser sounds like a really great idea! :wink:

“…and stuff”. hehe

Thanks again!


JUST IN CASE you haven’t had experience with vinyl, we use what’s called “transfer tape”, which you apply to the vinyl after weeding and then you peel off the backer paper and the WHOLE THING goes down on your substrate (like the side of yer pickup!) all in one go, you squeegee it on, then you peel the transfer tape away.

Thanks for the video! :slight_smile:

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We used regular masking tape in the AF. We stick the tape to our t-shirts first to kill some of the sticktion. Then the joy of going around the edges with sealer. If you didn’t seal the edges at around 600 mph they peel off, sometimes sooner.