or just buy one of the cricut blade holders. Could you really make it for much cheaper?
http://www.joann.com/joann/catalog/p...ODID=xprd74845
Build your own inexpensive DIY swivel drag knife for your CNC mill.
To make your own DIY Swivel Drag Knife Cutter all you need are:
1. one .25" x .125" rare earth magnet from Amazon.com
2. one 5mm OD, 2mm ID bearing from Boca Bearing Company :: Ceramic Bearing Specialists
3. one 4mm OD, 1.5mm ID bearing from Boca Bearing Company :: Ceramic Bearing Specialists
4. one 3/8" x 12" brass tube from Hobby Town USA or your local hobby store
5. three Carl Goldberg 3/16" wheel collars from Hobby Town USA or local hobby store
6. one spring that slides easily down the 3/8" brass tube, has an ID > .25" and a compression force of 80-150 grams when compressed 3/16"
7. Roland replacement blades 45 or 60 degree from Ebay.com
8. A copper pipe cutter such as a Rigid Model 104.
9. A tiny amount of thin CA (Cyanoacrolate also known as Super Glue)
10. A tiny amount of Loctite 609
11. Digital calipers (very helpful)
To read the complete article go to:
Build Your Tools ? View topic - DIY Stencil Cutting Drag Knife Solution - Update 5!
airnocker
Everything depends on everything else.
Similar Threads:
or just buy one of the cricut blade holders. Could you really make it for much cheaper?
http://www.joann.com/joann/catalog/p...ODID=xprd74845
Buying a replacement blade holder may be the best solution for many people, but then one must make a threaded mounting adapter for the retail blade holder so it mounts on their particular CNC mill.
I made TWO swivel knife blade holders that mount easily in my CNC mill for under $15. So, yes, it can be done cheaper and be of better quality for those wanting vinyl/stencil cutting ability with their CNC mills.
I bought a Roland replacement blade holder for $20 and it doesn't pivot nearly as well.
Thanks for posting the Joann web link though. I'm always interested in learning new sources.
There is a typing error in item #3 - the OD should read 5mm not 4mm.
Also item #5, Carl Goldberg wheel collars are not available any more but similar collars are available from Dubro or Great Planes brands. As you might have guessed I have these CG collars for a very long time.
This correction has been made in the buildyourtools.com forum as well.
I apologize for this oversight.
Does anyone know of a swivel knife compensation software package/processor/library? By compensation I mean what is described here
http://www.a2mc-cnc.com/downloads/do...g%20Knives.pdf
as well as a way to specify the blade's initial plunge angle for a free-swivelling blade.
Perhaps the most useful method of compensation would be to post-process a vector file (such as svg, wmf, dxf, etc) before sending it to the cutter. This would remove the cutter vendor dependency.
We were going to tackle this ourselves but thought if one existed...
Thanks for any help. -Mike
airnocker
Everything depends on everything else
So how does the knife turn into the angle it's cutting, is that just standard output for Mach3-Mill?
Otherwise when cutting a radius the knife would bind in the material, or when cutting a right angle the blade needs to leave the work twist 90 deg and re-enter the work again.
I suppose I could be over thinking things but I'm used to just setting an offset and turning on a spindle, is there some other step needed to add the knife to the mill?
Sorry I really have no idea.
Website [url]http://whatisacnc.com[/url]
The diameter of the blade post is very small. This makes the offset between the cutting tip of the blade and the center of blade pivot rather negligible for objects of about an inch higher or taller. For small objects, half-inch high or so, then corner rounding becomes more apparent.
Since the blade is trapped by the upper and lower bearings, and because the tip of the blade is tiny, the blade swivels in response to direction change just like a caster wheel does on a computer chair.
This post should answer this question and the one that followed.
airnocker
Everything depends on everything else
So the drag on the knife makes the blade swivel! I like that, but the 90 deg angle part has me a little concerned, how evident is it in material say 1/4" thick ?
I still want to try this because .... well... It just kicks but all the way! This would be Good for making a design for a shirt or something.
Website [url]http://whatisacnc.com[/url]
[QUOTE=crob09;1344352]So the drag on the knife makes the blade swivel! I like that, but the 90 deg angle part has me a little concerned, how evident is it in material say 1/4" thick ?
I still want to try this because .... well... It just kicks but all the way! This would be Good for making a design for a shirt or something.[......what is an "Engraving MOP" or "MOP"? /QUOTE]
Drag knife cutting is only meant to be used on very thin materials such as adhesive backed mylar or vinyl. You would never cut material more than .008-.010" thick.
Did you view my article with photos on the BuildYourOwnTools Forum link provided in my CNC Forum post?
An MOP is a CNC term that stands for "Machining Operation"..
What kind of Mach3 setup are you referring to? Do you not have an operational CNC machine?
airnocker
Everything depends on everything else
Thanks for the information, I didn't know that drag cutting was only for thin material, but it's still worth looking at and very interesting. I have a number of operational cnc's just wondering how I cut with a blade is all. I did check your link like many people do I'm sure, however I'm still here asking questions.
Are you insinuating that I stop looking into this?
[QUOTE=airnocker;1344354]
Website [url]http://whatisacnc.com[/url]
[QUOTE=crob09;1344378]Thanks for the information, I didn't know that drag cutting was only for thin material, but it's still worth looking at and very interesting. I have a number of operational cnc's just wondering how I cut with a blade is all. I did check your link like many people do I'm sure, however I'm still here asking questions.
Are you insinuating that I stop looking into this?
So sorry for my late reply, but recent flooding in my area cut fiber cables that bring my cable Internet service to me. I've had no Internet since Friday until today.
Will be happy to try and answer any questions you have. Just think of drag knife as a v-cutter tool doing engraving at very shallow depths of cut. Since the drag knife is spring loaded you have to find the right amount of down pressure (spring load) to cut through the adhesive material but not the backing, or in the case of no adhesive backing, just through the material thickness and not into the backing surface or spoil board.
Like other CNC "cuts" one has to try different settings in order to find the "sweet spot".
You can buy replacement blades for Stika or Crickett machines on-line for around $20 US, This includes the spring-loaded blade holder, bearings, magnet,etc. but they have to be converted to be mounted on a CNC machine. You would have to come up with your own way of adapting it to work with your CNC machine.
I bought one just to see how it might work but I really liked mine better.
airnocker
Everything depends on everything else
Airnocker ?, you must fly Champs?
Just thought I would post this to encourage anyone who is unsure if it works.
Thanks for posting your plans for the cutter, but I must disagree with you on one point! Your design works better than you realize! It's not limited to .010" material. I built mine as soon as you posted the plans and it has worked perfectly ever since. I often cut .040 sandblast resist mask with it, even with cursive letters down to 1/4" high with no real problem. I do have to run the program 3 times to get through, but that's ok. I use it to make stencils to sand carve glass. One mod I made to your design was instead of using a spring to set the pressure, I use weights, installed on a pin that extends up. This lets me just drop on a specific weight that I have found works for whatever material I am cutting. The other advantage is that an uneven table surface is not a concern, with small springs, spring rate may not be constant if the table slopes, with weights that's not a concern. I use my machine for many different types of cnc work, so setup has to be quick. I can just through an old piece of countertop on my table, tape the material to it and cut.
Hi planebuilder,
So there is an apparent aviation connection for you as well. RC? RV's?
Yes, hundreds of hours in the L-16, 7AC's and Sedan. I love the Champ, in particular the 85 hp variety. I love taildraggers.you must fly Champs?
Thanks for your feedback. I'm glad to hear that my design is far more capable and I think the weight-on-pin idea for cutting pressure is genius. This is a great tip.
airnocker
Everything depends on everything else