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Thread: CAD files for knife blanks

  1. #1
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    CAD files for knife blanks


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    This may have already been posted, but I'm curious as to how many people here use a CAD program (any kind) to draw out their knife profiles to have them cut out using a laser cut or plasma cutting system? And, does anyone draw only in 2D? Also, what advantages or disadvantages are there to laser cutting or plasma cutting blades from a CAD file? And finally, could either of these processes damage or otherwise compromise the integrity of the metal if blade blanks were profiled out this way? I would appreciate your opinion(s). Thanks.

  2. #2
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    You are not going to damage the steel in any way. The only thing is you might end up with a little bit of air hardened edges. Lasers, and plasma cutters move pretty quick, so it shouldn't be too bad. The plasma I program cuts 1/4" steel at about 300 inches a minute, and the material still gets pretty hot.
    Bob

  3. #3
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    I use one whether I have them cut or do so by hand. It's easier for me since I'm artistically challenged with a pencil. Since I am only wanting them profiled to finish by hand I use a 2D program.

  4. #4
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    It is my opinion that things designed in CAD frequently look like they were designed in CAD. I think it is all the straight lines and constant radius curves, they don't look natural to me. I have seen some prominent knife makers with amazing artistic talent make some mediocre designs because they used CAD and the CAD tool ended up driving the design.

    I personally have a lot of hours using CAD, probably more than most anyone on this board, but I still have to design on paper first. I have to use CAD in order to machine my designs. So I draw them in paper first and scan them in and trace them in the computer using NURB splines. This is the only way I've found to prevent the knife from looking too "CAD".

    I'm not saying that is a bad look (especially on a tactical), but unless that is the look you're going for, I think one must be very carful using CAD in their process.

    Here is an example of a knife designed in CAD that I feel escaped the "cad design" look fairly well:

    http://i566.photobucket.com/albums/s...d/cadknife.jpg

    But I set out with a design on paper and a plan in my mind to achieve the look I wanted, without letting the CAD tool just do whatever.


    "Build a man a fire and he'll be warm for a night. Set a man on fire and he'll be warm the rest of his life"

    KMG flat platens, radius platens and water cooled chillers: http://www.bladeforums.com/forums/sh...ad.php/1222480

  5. #5
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    Quote Originally Posted by MadBug View Post
    You are not going to damage the steel in any way. The only thing is you might end up with a little bit of air hardened edges. Lasers, and plasma cutters move pretty quick, so it shouldn't be too bad. The plasma I program cuts 1/4" steel at about 300 inches a minute, and the material still gets pretty hot.
    Bob
    Bob,
    Thanks for verifying what I suspected, but wasn't sure about. I have encountered one knifemaker's website who chooses not to use cut out blanks and cited material possibly being ill-affected as his reason for not cutting them out in the manner I was asking about. I appreciate you taking the time.

  6. #6
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    CAD knife

    as Nathan
    I draw them in paper first and scan them in and trace them in the computer using mastercam this way I can print 1/1 scale and use as a temple, glue to my stock and saw, grind , drill hole positions save the file for the future print
    I am a cnc programmer I program watherjet and laser But I do not own a machine so I do all the job by hand in my garage I like the handmade look on the knife curbs and shape are more artistic this way

  7. #7
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    Quote Originally Posted by WDZ Knives View Post
    I use one whether I have them cut or do so by hand. It's easier for me since I'm artistically challenged with a pencil. Since I am only wanting them profiled to finish by hand I use a 2D program.
    WDZ Knives,
    Thanks for posting. Sounds like you & I are in the same "artistically challenged" boat when it comes to utilizing a pencil to change an idea into a picture. I have been interested in knife making for several years now and still don't do too well drawing them by hand. I recently found a free CAD program that works almost just like AutoCAD. Same basic tool layout, most commands are similar as best I can tell, even though some commands are a bit different. The program also has a stand alone "sister" program that allows you to convert a DXF file back to a DWG file that you can then modify in the CAD program. I was using another program for making vinyl stickers and discovered that it has the ability to EXPORT files in a DXF format. I recognized this file type from having used AutoCAD previously. So, in a nutshell, I can "trace" a knife profile that I like from just about any picture and EXPORT it as a DXF file, then convert it to a DWG and then open it in the CAD program and edit it however I choose. This may seem a bit too much trouble to some, but in less than one day of using the CAD program I've taught myself to take any picture of any given knife and in just a few minutes I can produce an editable DWG file! I have been wondering for the past few years how I could go about doing this and I finally figured out a way. The vinyl cutting program is also free. It really is not difficult to learn to use either. It basically is a vectorizing program that can be used for drawing practically anything. I just wanted to get some input from a few others who design knives to see what were their thoughts on the subject.

  8. #8
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    Quote Originally Posted by Nathan the Machinist View Post
    Nathan,
    Good looking knife! Awesome work on the CAD file also! Thanks for the response.

  9. #9
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    Quote Originally Posted by Nathan the Machinist View Post
    It is my opinion that things designed in CAD frequently look like they were designed in CAD. I think it is all the straight lines and constant radius curves, they don't look natural to me. I have seen some prominent knife makers with amazing artistic talent make some mediocre designs because they used CAD and the CAD tool ended up driving the design.

    I personally have a lot of hours using CAD, probably more than most anyone on this board, but I still have to design on paper first. I have to use CAD in order to machine my designs. So I draw them in paper first and scan them in and trace them in the computer using NURB splines. This is the only way I've found to prevent the knife from looking too "CAD".

    I'm not saying that is a bad look (especially on a tactical), but unless that is the look you're going for, I think one must be very carful using CAD in their process.

    Here is an example of a knife designed in CAD that I feel escaped the "cad design" look fairly well:

    http://i566.photobucket.com/albums/s...d/cadknife.jpg

    But I set out with a design on paper and a plan in my mind to achieve the look I wanted, without letting the CAD tool just do whatever.
    Nathan,
    I can see what you are saying, but at the same time I don't see that being an issue for the way I am creating files for CAD since I can edit the file in the vectorizing program first. I am able to change any feature/line on a particular knife and then send it to the CAD program. The CAD program keeps, as best I can tell, exactly what I EXPORT. If you are interested to see what I mean I'd be happy to take a picture of your choosing to convert to a DWG file and email it to you or post it here for you to download. Please don't misconstrue this post as any kind of a challenge or as sarcastic. That's not my intent at all. I have been fortunate over the years to have the benefit of others' "trial and error" experience that has saved me the time they had to invest to learn what they did. That was the idea behind this post initially. Thanks again for posting.

  10. #10
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    Too bad my Pro/E, AutoCAD, or CorelDraw don't have freehand french curve functions!!

    I draw by hand, then scan, then import into cad so I can trace with very many short splines. That way I have a permanent template of every knife I make, and I can print as many as I may need for profiling, etc.

    Mike L.

  11. #11
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    Quote Originally Posted by logem View Post
    Too bad my Pro/E, AutoCAD, or CorelDraw don't have freehand french curve functions!!

    I draw by hand, then scan, then import into cad so I can trace with very many short splines. That way I have a permanent template of every knife I make, and I can print as many as I may need for profiling, etc.

    Mike L.
    Mike,
    The way I do it you don't need to have a french curve ... it's built into the vectorizing software. Shoot me a picture of a knife you'd like to have as a CAD file & I'll whip it out for you real quick. I'll be online for about 20 more minutes. That's plenty of time to do it.

  12. #12
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    I have used Photoshop for years. So I draw in Photoshop. I can save it to JPG the transfer to cad or a cad cam program. Instead of laser or plasma cutting. Look into WaterJet. I have drawn an image with Pencil scanned it into computer and print out templates. These can transfer into Cad.

  13. #13
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    I usually sketch things on paper first then scan it. I then use Adobe Illustrator to layout how the whole thing looks and then I copy my illustration and remove all but the outlines to get my template. I can take the outline and save as DXF if I want to send it out for waterjet, but so far I have only done them by hand. I just print them on a heavy paper and stick them down to my steel.

    TIP: One trick I have been using to make the paper patterns more durable is to spray them with clear spray paint until the paper is soaked through and let it dry, then apply it to the steel. The paint helps the paper resist coming apart when it gets wet with water or cutting fluid.

    I make my outlines black except for the areas where I'm going to drill. The dot on my optical punch is black so I use blue on the drawing where there are crosshairs so I can easily see where to line it up.

    Rendering it in Illustrator allows me to experiment with different handle variations and curves to tweak the design visually before prototyping it.

    Here's an example.
    Last edited by clw3; 12-15-2009 at 04:59 AM.

  14. #14
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    Quote Originally Posted by BlackToe Knives View Post
    Look into WaterJet.
    Who do you recommend for waterjet work?

  15. #15
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    Quote Originally Posted by logem View Post
    Too bad my Pro/E, don't have freehand french curve functions!!

    Mike L.
    It does. It is called ISDX "style" feature, and it is one of the best in the industry. Just like useing adobe illustrator, except 3D.


    "Build a man a fire and he'll be warm for a night. Set a man on fire and he'll be warm the rest of his life"

    KMG flat platens, radius platens and water cooled chillers: http://www.bladeforums.com/forums/sh...ad.php/1222480

  16. #16
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    Quote Originally Posted by EZ Cad Blades View Post
    Nathan,
    I can see what you are saying, but at the same time I don't see that being an issue for the way I am creating files for CAD since I can edit the file in the vectorizing program first. I am able to change any feature/line on a particular knife and then send it to the CAD program. The CAD program keeps, as best I can tell, exactly what I EXPORT. If you are interested to see what I mean I'd be happy to take a picture of your choosing to convert to a DWG file and email it to you or post it here for you to download. Please don't misconstrue this post as any kind of a challenge or as sarcastic. That's not my intent at all. I have been fortunate over the years to have the benefit of others' "trial and error" experience that has saved me the time they had to invest to learn what they did. That was the idea behind this post initially. Thanks again for posting.

    Sure, not at all. Mine was just a cautionary tale. If you're doing it right, you're doing it right.

    Re: your "challenge"

    Here is an easy one. It is easy to do well, it would also be easy to do badly.



    Trace that and I'll give you my opinion of your efforts.



    Though I'll point out, my concern is more about creating in the computer in the first place. For a lot of folks, is it an awkward canvas to create in , and it frequently shows...


    "Build a man a fire and he'll be warm for a night. Set a man on fire and he'll be warm the rest of his life"

    KMG flat platens, radius platens and water cooled chillers: http://www.bladeforums.com/forums/sh...ad.php/1222480

  17. #17
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    I have real trouble drawing too, and doing it in CAD...well, that's just a whole order of magnitude of difficulty added on top.

    My designs have improved significantly with the use of French curve templates and several erasers handy, trying different lines over and over and over again.

    I love having a photocopier close by too. I start with a photocopy of a design printed from a magazine, or photo lifted from the web. The photocopies then makes copies, adjust the sizing and I make my changes on those copies ....again and again...

  18. #18
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    template

    clear spray paint over the paper
    great tip Thank you
    GV
    Quote Originally Posted by clw3 View Post
    I usually sketch things on paper first then scan it. I then use Adobe Illustrator to layout how the whole thing looks and then I copy my illustration and remove all but the outlines to get my template. I can take the outline and save as DXF if I want to send it out for waterjet, but so far I have only done them by hand. I just print them on a heavy paper and stick them down to my steel.

    TIP: One trick I have been using to make the paper patterns more durable is to spray them with clear spray paint until the paper is soaked through and let it dry, then apply it to the steel. The paint helps the paper resist coming apart when it gets wet with water or cutting fluid.

    I make my outlines black except for the areas where I'm going to drill. The dot on my optical punch is black so I use blue on the drawing where there are crosshairs so I can easily see where to line it up.

    Rendering it in Illustrator allows me to experiment with different handle variations and curves to tweak the design visually before prototyping it.

    Here's an example.

  19. #19
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    Good info here....

    EZ Cad - I have seen laser blanks with melted tips. Waterjet is usually a higher-quality cut.

    Holes that are laser-cut are often very hard on tooling, even on steels that are "water hardened". I got a lot of 1075 laser-cut blanks that destroyed an HSS countersink, then a cobalt countersink, then an indexable carbide countersink. YES I was using proper RPM and coolant (but not a rigid setup). I ultimately had to anneal the blanks to machine them.

    Also, its easy to talk about drawing in non-CAD programs, and exporting to dxf/dwg formats to send to a laser/WJ shop. Doing it is another thing.

    File conversion and export is a problematic task. This is more true when your vendor has old software and old machines; less true when your vendor has new software and new machines.

    Many times, the resulting file has unintended features, such as extra geometry, nodes, or control points; or missing geometry (gaps). 0,0 displacement or unit of measurement (inches vs mm) is also a common goof. Waterjet software in particular is sensitive to these discrepancies.

    Even CAD files that are generated from dedicated CAD programs can be goofy.

    I'd also like to see you re-draw Nathan's challenge... show us your stuff!
    Patrick Brewster / flyingsteel.com / facebook

  20. #20
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    Quote Originally Posted by Nuke41 View Post
    Who do you recommend for waterjet work?
    http://www.greatlakeswaterjetinc.com/index.htm

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