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  1. #1
    Join Date
    Aug 2012
    Posts
    12

    Blackfoot Clone

    Well, seeing as this is my first thread on here. I may as well talk about myself as well. I am a hobbyist. I like to build/design/fix things. My First hobby was my computer. It's a beast of a machine and has cost me multiple thousands of dollars over the years but haven't had any games on it that have peaked my interest lately. I have many a project around the house finished and unfinished. I just recently built a DIY MDF/Plywood CNC machine that is working fairly well...it's just not big enough. The machines current work area is 39"x31"x5". Here are a couple photos of it.
    Attachment 223164 Attachment 223166Attachment 223162
    It was a nice learning experience, but I am wanting to go bigger. I first looked at the Blackfoot 4x8 CNC in the beginning and thought it would be too big of a task (and machine) to take on for a first build, but now I think I am ready for it. I have all my plans drawn up, and some parts already purchased. I am in the very early stages of the build but would like to keep a build log on here to show my progress. Here are pictures of the sketches of the machine just based on the pictures from their website and other people posting their "Blackfoot/blacktoe" machines. The machine will be pretty much the same as the one sold on the site but I plan on doing a floating dust shoe and then a cutting laser way down the road.
    Attachment 223168Attachment 223170Attachment 223172
    I couldn't bring myself to pay 500$ for the plans if there are dozens of pictures out there to give a pretty good idea of what shapes and measurements to use. I also am implementing the improvements of JC Ryan on youtube on how to make the machine more rigid by doubling up the bearings shown here
    Part 1
    and
    Part 2
    Although I didn't have any plans or real measurements to base this off of please don't ask for the dxf files as I spent around 36 hours drawing these up and am very proud of it, and wouldn't want to get in trouble with www.buildyourcnc.com for copying their design and spreading the files. Later on down the build I will message them to see if I could sell my plans. If they don't object then I will post a price.

    The current things I have purchased or already own:

    Bosch 2.25hp router of course
    All the electronics to hook up steppers and the computer
    x7 3/4"x4'x8' Medium Density Overlay Plywood for parts(not cut yet)
    x3 425oz/in steppers with matching drivers
    x1 651oz/in stepper with matching driver
    170ft of 4 conductor wire to hook up new machine
    500 1.5" 1/4-20 black oxide hex bolts
    360 1/4-20-3/4 cross dowels

    Feel free to ask any questions or comment on it.

  2. #2
    Join Date
    May 2005
    Posts
    3920

    Works fairly well isn't a ringing endorsement.

    I only titled this reply that way because I'm not convinced that the machine you are about to build will be much of an improvement over your current machine. The first thing that stands out is that the cross sections are rather thin, this means a flexy machine with lots of vibration chatter and what is otherwise poor performance.

    You are talking about a 4 x 8 router which is fairly large. For a machine made out of wood products a fairly large box beam is in order. Probably on the order of 8" square. I say wood products because because I'm no fan of working with MDF and would prefer a good quality plywood. In this case a birch plywood. That is if I had to make the beam out of wood. You should seriously consider steel or aluminum beam. In general you will want a more robust machine to get all around better results than your previous machine.

    I only mention this because you sound like you are at best fairly satisfied with the current machine. I'm reading that as another way to say I'm frustrated with my current machine. Remember I'm basing my opinions of your new machine upon how it looks in your drawings. That is where the "it looks thin" comments come from.

    In any event there are a couple of other very recent threads posted here that explore the design of a gantry. One poster goes to great length to explain stiffness in the gantry beam and its importance to machine operation. In effect the gantry beam is a weak point in most router designs. So before you go too far you may want to explore what your goals are.

  3. #3
    Join Date
    Aug 2012
    Posts
    12
    I am all for taking suggestions and still find myself changing my plans day to day to find something I missed or didn't double check. I think I can make the gantry cross section larger without much issue. I also didn't say I would be using MDF. MDO will be what I use and is a little bit more pricey but worth it due to the varying humidities. (Medium density overlay panel, or MDO panel, is a paintable surface made of plywood with a weather-resistant resin overlay bonded to the wood by heat and pressure. The overlay, which has at least 27% resin content, resists water, weather, wear and degradation.) [taken from wikipedia] Later on the gantry can be converted to aluminum or similar while keeping the torsion box underneath intact.
    I used another design feature of the "GreenBull" machine they have as well to hopefully make the gantry more rigid.

    Attachment 223332
    This is the after and before picture (in order)

    Attachment 223334
    This measurement in the picture is 4" but like I said could be increased to something larger if needed.

    I was also looking into using "openrail" with the setup. Has anyone here had experience with it and do you do anything special where to pieces meet to not have a "bump"?

  4. #4
    Join Date
    May 2005
    Posts
    3920
    Quote Originally Posted by kmyerslp View Post
    I am all for taking suggestions and still find myself changing my plans day to day to find something I missed or didn't double check. I think I can make the gantry cross section larger without much issue. I also didn't say I would be using MDF.
    I must have misunderstood your intentions with MDF. Personally I hate working with MDF even if at times it is the right material for the job. So maybe my bias against MDF is coming through!
    MDO will be what I use and is a little bit more pricey but worth it due to the varying humidities. (Medium density overlay panel, or MDO panel, is a paintable surface made of plywood with a weather-resistant resin overlay bonded to the wood by heat and pressure.
    I'm familiar with the stuff, it comes in variants suitable for concrete forms or outdoor signs. Most of the panel sieve worked with are of above average quality and certainly better than home center lumber.
    The overlay, which has at least 27% resin content, resists water, weather, wear and degradation.) [taken from wikipedia] Later on the gantry can be converted to aluminum or similar while keeping the torsion box underneath intact.
    True you can do a conversion later but you can also do a substantial beam in plywood that might be surprisingly good for your needs. You will effectively trade time building the beam for a cost savings.
    I used another design feature of the "GreenBull" machine they have as well to hopefully make the gantry more rigid.

    Attachment 223332
    This is the after and before picture (in order)
    The uprights don't look to be substantial to me. I'd build a box beam for the uprights or layer up the flat sections. Again this is based upon looks without specific information.
    Attachment 223334
    This measurement in the picture is 4" but like I said could be increased to something larger if needed.
    It wouldn't add a huge amount of material to the project to widen that dimension a bit. Part of the trick to building a solid gantry beam is making sure the beam can resist twisting. Part of that is achieved via a large cross section and part by adding internal gussets or baffles. The reality is that it is fairly easy to build a well reinforced wood beam as the gussets can be glued in place as part of the build process.
    I was also looking into using "openrail" with the setup. Has anyone here had experience with it and do you do anything special where to pieces meet to not have a "bump"?
    Never used the stuff! However more rollers would likely smooth out the bumps.

  5. #5
    Join Date
    Jan 2014
    Posts
    50
    in the 2nd video, why were you turning the drill bit instead of pushing on it like in the 1st video?

  6. #6
    Join Date
    Aug 2012
    Posts
    12
    I can most definitely add more pieces Inside the gantry and widen that measurement to prevent twisting. There is only the motor mount in there for a gusset. I will add an additional 4 to this to help out. As for the uprights being turned into a box beam I will have to figure something out to add that to the design.
    Thank you again for your advice wizard, I appreciate it.

    scott0999 - The videos aren't mine but still after watching it again he doesn't spin the bit, he still pushes on it like in the previous.

    Sent from my HTCONE

  7. #7
    Join Date
    Jan 2014
    Posts
    50
    Quote Originally Posted by kmyerslp View Post
    scott0999 - The videos aren't mine but still after watching it again he doesn't spin the bit, he still pushes on it like in the previous.
    my apologies, I was assuming it was yours.

    I got confused because in the first video it looks like a deflection test, then in the 2nd video it looks more like a runout test with a little pushing.

  8. #8
    Join Date
    Aug 2012
    Posts
    12
    Got some new parts in for the new machine.
    651oz/in stepper with dual 1/2" shafts
    driver to run it
    360 1/4"-20-3/4" cross dowels
    Click image for larger version. 

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  9. #9
    Join Date
    Apr 2006
    Posts
    3498

    Re: Blackfoot Clone

    Any progress
    http://free3dscans.blogspot.com/ http://my-woodcarving.blogspot.com/
    http://my-diysolarwind.blogspot.com/

  10. #10
    Join Date
    Aug 2012
    Posts
    12
    Quote Originally Posted by Khalid View Post
    Any progress
    The machine was finished a couple months after that post. I have made many modifications to it since then. The attached photo is the most recent one and is 6 months old.

  11. #11
    Join Date
    Apr 2006
    Posts
    3498

    Re: Blackfoot Clone

    Thanks for the updates.. looking very nice... I am also planning to make 4ft x 8ft router similar like this... need some info if you can give me... What is the precision/accuracy of the machine... when you making a big hole using pocketting operation do you get round circular hole?.. what maximum cutting speed without compromising quality of cut?... Addition to this do you find any racking in the machine? do you have two homing switches on the longer axis? if NO how you manage to square your router?
    Again, i know u will have no available plan dxf/dwg but if you have any rough plans u can share i want to get just an idea...
    Thanks
    http://free3dscans.blogspot.com/ http://my-woodcarving.blogspot.com/
    http://my-diysolarwind.blogspot.com/

  12. #12
    Join Date
    Aug 2012
    Posts
    12
    Quote Originally Posted by Khalid View Post
    Thanks for the updates.. looking very nice... I am also planning to make 4ft x 8ft router similar like this... need some info if you can give me... What is the precision/accuracy of the machine... when you making a big hole using pocketting operation do you get round circular hole?.. what maximum cutting speed without compromising quality of cut?... Addition to this do you find any racking in the machine? do you have two homing switches on the longer axis? if NO how you manage to square your router?
    Again, i know u will have no available plan dxf/dwg but if you have any rough plans u can share i want to get just an idea...
    Thanks
    Accuracy .01 - .05 maybe? Ive honestly never tried calculating it.

    Circular holes? - yes, no reason not to unless your machine is calibrated wrong.

    Speed bs quality - I have tried for speed without sacrificing quality but i see 100-200ipm on larger projects with .25 bit and 3/8 doc.

    Racking - No, the machine has one motor for the long axis centered in the gantry with "axles" coming out both sides. At the end of each of those is a sprocket.

    Homing switches - No, I have a block of wood to set the 0 position of the 48" axis and just visually see the "0" of the x axis. I care more about zeroing to my project than homing the machine currently.

    Squaring - squaring is done by the eye bolts at the end of the table. First I get the tension of the chains where I want it and then I cut a 90 degree angle in the table. I use a square to check if the gantry is perpendicular. If not I stay on the same side of the table, loosen one eye nolt half a turn while tightening the other half a turn. I keep repeating this process until im satisfied its square.

    Plans - There are no rough plans really. There are the drawings I made and thats it. :/ sorry

  13. #13
    Join Date
    May 2005
    Posts
    3920

    Re: Blackfoot Clone

    Quote Originally Posted by kmyerslp View Post
    The machine was finished a couple months after that post. I have made many modifications to it since then. The attached photo is the most recent one and is 6 months old.
    I must say it does look nice!

  14. #14
    Join Date
    Jul 2017
    Posts
    347

    Re: Blackfoot Clone

    A machine made out of plywood? What is wrong with people lol....whatever happened to well built accurate machines made of steel aluminum brass ?

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