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IndustryArena Forum > WoodWorking Machines > DIY CNC Router Table Machines > GME's New 80/20 CNC Build - My Design
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  1. #181
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    Re: GME's New 80/20 CNC Build - My Design

    Quote Originally Posted by wmgeorge View Post
    Thats worse case, the calibration Certificate that came with it, was more detailed and concise. Makes you wonder what the cheaper ones are at?

    Agreed, it's the worst case. I suspect that the error increases the wider you open the jaw, but I have no empirical evidence to support my suspicion. Interestingly, +/- .001 seems to be common, even with the cheaper ones. But then, I don't believe everything I read in advertising, and the cheap ones don't come with calibration certs - at least not the ones I've seen.

    I don't think I mentioned it, but I bought a Vista CNC pendant. I got the P2-S. Pretty nice, and way better than the Shuttle Pro I had been using. It was a snap to set up.

    Gary

  2. #182
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    Re: GME's New 80/20 CNC Build - My Design

    Yes I have one of the Vista CNC pendants also and I love it. Mine is USB, I wish now it was WiFi but I use it all the time. Looking forward to seeing your machine making something Gary. I am stalling off a Honey Doo job
    and hope to get back to running the CNC.
    Retired Master Electrician, HVAC/R Commercial. FLA Saturn 2 4x4 CNC Router Mach4 Kimber 1911 45ACP

  3. #183
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    Re: GME's New 80/20 CNC Build - My Design

    Quote Originally Posted by wmgeorge View Post
    Yes I have one of the Vista CNC pendants also and I love it. Mine is USB, I wish now it was WiFi but I use it all the time. Looking forward to seeing your machine making something Gary. I am stalling off a Honey Doo job
    and hope to get back to running the CNC.
    I wish I had a wireless too. I know what you mean about honey do's. I have a long list of them.

    I got my new spindle cable installed. I used a ferrite core at the VFD end, in my quest to fend off noise. According to what I've read, I did it wrong the first time around. I've read that you don't include the ground wire in the windings around the core. Got it corrected this time.

    I ran my spindle today. Seems quieter than before, but it's been a long while since a ran it, so I can't be sure. I don't have a means of measuring noise, which is a handicap. I have a TV close to my CNC. I sometimes plug my computer into it for a larger screen. Anyway, I was able to position the spindle to within about 18 inches of the TV and looked for noise it. Nothing but its normal good picture. Should I see noise in the TV, if I was putting any out? This is the sort of thing you know about, and I don't.

    I'm setting up to do gantry squaring. I'll take some photos for my report out. After that, I'll do my spoilboard. Once the spoilboard is done, it's time to start cutting. I'm working on toolpaths for mounting the spoilboard and cutting dadoes for the t-track I'm planning to use. I have to inventory my supply of t-track. I don't think I have enough 4 foot lengths.

    Gary

  4. #184
    Thank you, the article is very helpful

  5. #185
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    Re: GME's New 80/20 CNC Build - My Design

    Gary I have both a Oscilloscope and RF Signal strength meter which is broad banded. But I have used an AM/FM radio in the past to check for noise when I was active in Ham radio. Did you have problems with the machine you had running before?
    Retired Master Electrician, HVAC/R Commercial. FLA Saturn 2 4x4 CNC Router Mach4 Kimber 1911 45ACP

  6. #186
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    Re: GME's New 80/20 CNC Build - My Design

    Quote Originally Posted by wmgeorge View Post
    Gary I have both a Oscilloscope and RF Signal strength meter which is broad banded. But I have used an AM/FM radio in the past to check for noise when I was active in Ham radio. Did you have problems with the machine you had running before?
    I didn't try a radio, but I'll give it a shot. Thank you for the suggestion.

    No, I didn't have an noise-related problems before, so I didn't expect any this time around. The only changes I made were replacing the cable between the spindle & VFD, grounding the cable at the spindle (back when, I added a ground under the spindle cap), and changing the way I did my windings on the ferrite torroid core. All of the changes should serve to reduce noise, so I didn't expect to have a problem now. About the only additional thing I could add would be a noise filter on the incoming 240V line. They aren't particularly expensive, and not at all complicated to install, but I don't plan to go the time and expensive, if I don't need it.

    Thanks again for the suggestion.

    Gary

  7. #187
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    Re: GME's New 80/20 CNC Build - My Design

    Quote Originally Posted by qtvietnam View Post
    Thank you, the article is very helpful
    You are welcome. I am glad to be of service.

    More to come.

    Gary

  8. #188
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    Re: GME's New 80/20 CNC Build - My Design

    Quote Originally Posted by wmgeorge View Post
    I have used an AM/FM radio in the past to check for noise when I was active in Ham radio.

    Bill, I gave the radio a shot. On AM band, I got quite a bit of noise. I tried a couple of talk radio stations. With the spindle running at 18,000 RPM, I went from being able to clearly hearing the voices, to just being able to make out what they were saying. I then switched to FM. It was okay, Maybe a tiny bit of noise, but hardly discernible. The radio was 2-3 feet from the spindle during the test.

    The machine itself appears to be working fine. No noise showing in my control computer. My TV is still not showing signs of noise.

    How does your experience with Ham radio to compare to my observations?

    Right now, I'm a little concerned about the noise, because I'm about to work on squaring my gantry. The technique I'm using requires running the axes over a large are and running the spindle to drill holes. If something is misbehaving, there is no way to know for sure. I'd hate to go to all the work squaring the gantry only to find out later that I was dropping or gaining steps and all the work was wasted.

    To add a brief recap, I have an HY 2.2KW VFD, which is in it's own box and physically separated from my control box; spindle is grounded inside the cap; ground wire connects to VFD and runs from there to the star ground; Igus CF6 spindle cable with shield grounded at both ends - at the connector metal cable clamp at the spindle end and in an Icotek EMC Shield Clamp at the VFD end ; 3 hot spindle cable wires wrapped around ferrite torroid core - 8 turns each - between the Icotek shield clamp and the VFD. Here is a picture of the Icotek shield clamp, which is one that often shows up in mactec54's posts on grounding shielding in the VFD box:




    Gary

  9. #189
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    Re: GME's New 80/20 CNC Build - My Design

    Bill, I gave the radio a shot. On AM band, I got quite a bit of noise. I tried a couple of talk radio stations. With the spindle running at 18,000 RPM, I went from being able to clearly hearing the voices, to just being able to make out what they were saying. I then switched to FM. It was okay, Maybe a tiny bit of noise, but hardly discernible. The radio was 2-3 feet from the spindle during the test.

    The machine itself appears to be working fine. No noise showing in my control computer. My TV is still not showing signs of noise.

    How does your experience with Ham radio to compare to my observations?


    Just tune your AM to a station free area and turn on the spindle, if you hear a lot of static and don't when its off then you have RF leaking somewhere. Your TV is digital and may not be affected by the RF. I don't use those terminals, all mine are soldered... the shields that is. The power wires are crimped terminals. My VFD is in a metal enclosure with metal door grounded and the air intake vent is metal and grounded. Everything is grounded. I also have a better quality VFD, Hitachi and it was the second one I have used without issues. No line filters, never needed.

    I would wait and run your machine before doing anymore, it might be fine.


    Ham radio..... when we were trying to get distant stations like overseas Japan, Italy and etc the noise in the background noise would have to be very low. The power companies often did not give a rats behind if they had poor HV connections like on the 13.8 Kv primary. So I would take a AM radio and a sledge hammer and drive around until the radio had so much static you knew you were near a bad power pole wire connection. Walk over to the suspected pole and give it a wack with your sledge hammer, if it got worse then I would call it in. They were required by FCC and law Not to transmit interference. It raised hell with the AM and TV signals but nobody but us Hams knew where it was coming from.
    Retired Master Electrician, HVAC/R Commercial. FLA Saturn 2 4x4 CNC Router Mach4 Kimber 1911 45ACP

  10. #190
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    Re: GME's New 80/20 CNC Build - My Design

    I'm overdue for an update. Here it is. I squared my gantry.





    Since I don't have my spoilboard mounted yet, I used two scrap pieces of plywood for my squaring routine. Yes, there are 3 pieces in the photo, but the one in the center is to facilitate using my Woodpecker Bar Gauge measuring device (stainless rods held together with the red blocks shown sitting at an angle in the photos).

    I created several toolpaths in Vectric Aspire for the routine. The routines call for cutting 1/4" holes in a square pattern, 45" on each side. In the second photo, you will see a metal dowel pin in the 4th of 4 holes. I started by creating the first toolpath starting from the left, and subsequent toolpaths moving to the right, and maintaining the 45"/side square. That allows me to create a set of 4 holes, measure, make adjustments, and then rerun a new set of holes and keep track the holes I was working with. After cutting 4 holes, I inserted 1/4" metal dowel pins in each one. I had a good, tight fit, that required a hammer to tap in. The holes were cut to 3/8" depth.

    As far as measuring is concerned, I checked the two cross distances with the bar gauge to determine which diagonal was shorter. I locked in the gauge to the shorter length. Then, I placed the gauge across the other diagonal and observed the gap between one end and the dowel. I used feeler gauges to measure the amount of the gap and give me the start figure for adjustment.

    Here's how it works. Don't ask about the underlying math. I cannot explain it. It's been too many years since I studied geometry and trigonometry. I only know that it works.

    1. Determine the size of the square you want to use and make up toolpaths for it. The larger the square the better. You get better accuracy. I would have gone with 48" X 48", but for the fact that put my machine together with a setback in the front to allow me to do dovetail work off the front. So, 48" x 48" wasn't in the cards for me.

    2. As described above, cut the holes, insert dowel pins, and determine the difference in the distance between the diagonals.

    3. Now the math.
    a. Start by taking the difference between the diagonals and dividing it by 2 (half the error).
    b. Divide the result in a. above by the length of the side of the square.
    c. Multiply the result in b. above by the length of the gantry as measured by the center-to-center distance between the gantry mounting points.

    This gives you the amount you need to adjust your gantry.

    Here's and example.

    Given: My gantry is 74" in total gross length. The center-to-center distance between the mounting points is 69.5". This is also the center-to-center distance between my Y axis linear rails. 69.5" is the distance necessary for this example. The error observed in the dowel-to-dowel cross measures is .030". Each side of the square pattern is 45".

    Math: .030" dowel-to-dowel cross measure/2 = .015". (.015"/45") X 68.5" = 0.00033333333 X 68.5 = 0.022833333". So, with rounding, the amount to adjust the gantry is 0.023".

    Why do you adjust the error to account for the gantry length? Take 2 intersecting line angled 5 degrees. 1" from the apex the two lines will be X distance apart. At 48" from the apex, the two lines will be Y distance apart, and Y distance apart. The Y distance apart is multiples of the X distance. So, you adjust the measured error to extend it to the length pertinent to where you will make the actual adjustments.

    Here is a picture:



    So, how do you know which direction to move the gantry? Well, it depends upon which side of the gantry you want to move relative to the other side. Let's assume that when you measure the diagonals, the short measure is from the left front to the right rear and the long measure is from the right front to the left rear. That means that to adjust to square, you either need to move the left side of the gantry toward the front, or move the right side of the gantry towards the rear. If the long measure from the left front to the right rear, then adjustment is reversed, i.e., you either move the left side of the gantry to the rear, or move the right side toward the front. Another option is to split the difference, and move each side. Moving both side might be an option in cases of limited gantry adjustability.

    How did I make the adjustments on my machine? Glad you asked.

    1. I loosened all of the gantry mounting screws to finger tight, except for the rearmost outside screw on the side I wanted to be the fixed, pivot point. I left that screw just a little more than finger tight. It needed to be able to allow the gantry to rotate, but not slip around. (Note: having adjustability is a blessing and a curse. A blessing, because without adjustability you would be left with an out-of-square gantry. A curse, because having adjustability means there is want amounts to a degree of "slop", which can mean getting unwanted movement at the pivot point. Unwanted movement translates into an unsuccessful adjustment.)

    I placed a dial indicator on the linear rail corresponding to the side I am adjusting, and placed the end of the indicator against the plate I am moving. Here are 2 photos of the setup:



    The lower plate is fixed, i.e., mount to the linear rail blocks. The plate above it is what moves relative to the lower plate, so my dial indicator zeros off it.



    Then, I used a common F-style clamp at a diagonal to move the gantry in the desired direction - in this case, toward the rear. The dial indicator measures the amount moved.

    Because it is difficult to ensure that the opposite side remains stationary, this is a measure, adjust, repeat process. Fortunately, the errors tend to get smaller with each succeeding attempt. I dialed mine in on the 2nd attempt. Okay, you saw what appears to be 4 attempts in the 2nd photo, didn't you? I didn't count the first one, because I had a problem with the hole size.

    When I started the process, I intended to take a 1/4" endmill, drill the holes with it, and insert the dowels. The best laid plans. . . . Turns out the endmill cut too large a hole and the dowel wallowed around in it. Not good. On to Plan B. I rewrote to toolpaths to use a 1/8" bit to cut a pockect 1/4" diameter. That worked. I got the good tight fit I wanted. So, scratch the first set of holes. Set 2 got me close. Set three got me to within .001 over 45" and set four confirmed it.

    There was some earlier discussion about VFD/Spindle noise, and my attempts to eliminate, or at least minimize, it. It's still there, but so far so good. It looks like it's not so bad as to cause any problems - at least for now. If a problem shows up, I'll add a line filter.

    Next up:

    Spoilboard

    Gary

  11. #191
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    Re: GME's New 80/20 CNC Build - My Design

    I have a little problem I use some help with. I've found that it get quite a bit of vibration with movement. It's greater on the y axis, much less on X and no issue on Z. The vibration is more pronounced with short movements, i.e., under an inch. I reduced my velocity on Y from 600 to 300 and that helped some. I haven't played with acceleration yet, but I'm going to.

    All this led me to conclude that I should have bolted the CNC to my concrete floor. Doing so now is a problem. Here are a couple of photos to illustrate what I'm up against:



    This photo show the type of foot I'm using. The photo is deceiving, though. It looks like the foot sticks out beyond the extrusion, but it doesn't.



    This shot gives a clearer picture. The feet don't stick out.

    While not necessarily clear, I have a threaded plate on the bottom of the extrusion. The foot has a 1/2" threaded part that swivels some and screws into the plate on the extrusion. A pretty standard machine foot.

    If the feet stuck out, I'd just drill holes though them and into the floor, epoxy threaded rod into the concrete. Not and option. Not enough room to drill.

    The obvious solution would be to just start over - dismantle everything, add bolts in the floor and reassemble. Not something I want to do.

    I recall reading posts from Dave Faulkner about his 2 x 4 Saturn 2 (welded steel) slamming around pretty hard in operation and needing a substantial, or at least rigid, base to hold it. My machine is not as heavy as a Saturn 4 X 4, but it's nearly twice has heavy as the Avid/CNCRP Pro 4 X 4. I don't recall this being an issue with the Avid machines, but I've haven't gone on an extensive read trying find anything as yet. I feel like I'm overlooking something - probably something obvious. Suggestions???

    Any ideas short of a dismantle/rebuild?

    Thank you in advance.

    Gary

  12. #192
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    Re: GME's New 80/20 CNC Build - My Design

    Recall the discussion we had a while back when I suggested adding diagonal braces? I would start by adding those to the sides that did not have some installed.

    You've got slots in those legs, make up some 2 sided L brackets to fit and holes to match those slots. Weld at the sides. So you've enclosed two sides of one leg, both L bottoms bolted to floor, holes with bolts to slots. Trying to get Fusion 360 to export a JPG, but here is a screen shot. Pretty simple just make 2 for each leg, Weld at the long upright corner.
    BTW the best present I ever purchased for myself was a Bosch rotary hammer/drill, works great as a 1/2 drill motor and wonderful as a hammer drill. Makes drilling in concrete a breeze.
    Retired Master Electrician, HVAC/R Commercial. FLA Saturn 2 4x4 CNC Router Mach4 Kimber 1911 45ACP

  13. #193
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    Re: GME's New 80/20 CNC Build - My Design

    Quote Originally Posted by wmgeorge View Post
    Recall the discussion we had a while back when I suggested adding diagonal braces? I would start by adding those to the sides that did not have some installed.

    You've got slots in those legs, make up some 2 sided L brackets to fit and holes to match those slots. Weld at the sides. So you've enclosed two sides of one leg, both L bottoms bolted to floor, holes with bolts to slots. Trying to get Fusion 360 to export a JPG, but here is a screen shot. Pretty simple just make 2 for each leg, Weld at the long upright corner.
    BTW the best present I ever purchased for myself was a Bosch rotary hammer/drill, works great as a 1/2 drill motor and wonderful as a hammer drill. Makes drilling in concrete a breeze.
    Thanks, Bill. The photos I took don't tell the whole story. The feet stick out a little past each face. Maybe I make up the L and weld the L that attaches to the floor to the face of the L on the legs. That would might move it out far enough. I'll have to play with it and see if I can make something like you suggested work. I'd have to use some thicker metal on the legs to clear the feet.

    Adding the 2 cross pieces won't be as easy as one might think. The fasteners usually used to fix them won't fit. You need an open end to slide them in. I'd have to rig up a special fastening method - and more hours at the mill. Also, the extrusions will cost an arm & leg. All 80/20 is expensive. The 3 x 3 profiles especially so. The shipping is a killer. All-and-all, an ugly job. Interesting, but the Avid 4 x 4 has the brace we are talking about on only one side - used to hang the control boxes from. It's also mounted pretty high up on the legs. The other side is constructed like mine. You'd think that their machines would still suffer from vibration - especially since they are about half the weight. I wonder about that.

    I'll have to get a hammer drill. I have a lot of drills, but not one of those. I'll take a look at the Bosch. I will probably anchor to the floor first and see what I get. I'll add the braces, if anchoring doesn't do the job.

    Gary

  14. #194
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    Re: GME's New 80/20 CNC Build - My Design

    Buy some 3x3 inch or another size you think would work, 3/8 inch thick aluminum angle. Brace from the inside so you don't hit your legs on it. Drill the legs with 5/16 or 3/8 bolt or make plates.
    I thought they had twist in or other special bolts for those slots you could use?
    Retired Master Electrician, HVAC/R Commercial. FLA Saturn 2 4x4 CNC Router Mach4 Kimber 1911 45ACP

  15. #195
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    Re: GME's New 80/20 CNC Build - My Design

    Quote Originally Posted by wmgeorge View Post
    Buy some 3x3 inch or another size you think would work, 3/8 inch thick aluminum angle. Brace from the inside so you don't hit your legs on it. Drill the legs with 5/16 or 3/8 bolt or make plates.
    I thought they had twist in or other special bolts for those slots you could use?
    There are a lot of options surrounding 80/20, but the profile size is what it is. Nothing I can do about the 3 x 3 size.

    The 3 x 3 is attached with fasteners that fit in a special 13/16" milled hole at the ends. There are twist-in bolts, but they won't work in this application. With the special milled fastners, I'd have to use roll-in t-nuts, which are just okay. The milled fasteners are designed to use a 3" long t-nut with maximum bearing surface. Roll-in t-nuts bear enough to hold, but don't have all that much bearing surface. Makes sense. Otherwise, you couldn't roll them into the slot. Adding the additional 80/20 lengths can be made to work, but the installation won't be as stiff as it would be if installed with the proper hardware. Just the way it is.

    The twist-in bolts should work for mounting the legs to the floor. So would roll-in t-nuts. I keep both around, so it's just a matter of selecting the one I like best. The twist-in are much more limited, because there aren't many bolt sizes. I'll have to check, but I don't think they are long enough to mount 3/8" material. With the roll-in t-nuts, you can choose the bolt length you need. I think they may have twist-in t-nuts, but I'm not sure. If they do, twist-in nuts may work all around.

    Thank you for your suggestions, Bill. Much appreciated.

    Gary

  16. #196
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    Re: GME's New 80/20 CNC Build - My Design

    Gary, I was suggesting 3x3 by 3/8 inch thick aluminum angle for the bracing. Or any other suitable size angle, not the extrusions.

    Sorry about not drawing it up for you but I design in my head and I can visualize how to do it. Been doing it that way since as a farm kid 65 years ago I built my first gokart. Yes I can do CAD, it just slows me down.
    Retired Master Electrician, HVAC/R Commercial. FLA Saturn 2 4x4 CNC Router Mach4 Kimber 1911 45ACP

  17. #197
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    Re: GME's New 80/20 CNC Build - My Design

    Quote Originally Posted by wmgeorge View Post
    Gary, I was suggesting 3x3 by 3/8 inch thick aluminum angle for the bracing. Or any other suitable size angle, not the extrusions.

    Sorry about not drawing it up for you but I design in my head and I can visualize how to do it. Been doing it that way since as a farm kid 65 years ago I built my first gokart. Yes I can do CAD, it just slows me down.

    Thanks, Bill. I understand. I have to check, but I believe I have some 4" x 4" x 3/8" or 6" x 6" x 3/8" laying around. Not sure which, but either can be made to work.

    Don't give not drawing it out a second thought. I appreciate any help I can get, and certainly don't expect people invest a lot of time and effort. The drawing part is up to me. If I wasn't sure what you were suggesting, no reason why I couldn't draw it out and post it for review and comment.

    I'm the same way with design. I see it in my head and refine the details in my head. However, I usually draw it out in the end, or use CAD to model. CAD slows me down, but it also ensures that I haven't overlooked something important.

    Thanks again,

    Gary

  18. #198
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    Re: GME's New 80/20 CNC Build - My Design

    I stumbled on something to try to reduce vibration. I was poking around my shop and found 2 pieces of 4" x 60" x 1/4" cold rolled steel that was used on my first CNC. It was used as the skated bearing surface on the Y axis. It's a couple of inches longer than I need, which is way better than being too short. I'm thinking about putting putting the pieces on my mill, drilling holes to match up with the extrusion slots on the legs and bolt it to the outside faces of front and back legs. Not as good as pieces fit between the legs, but it's cheaper than buying new extrusion pieces, milling, and fitting them. I'd rather not drop another $250-$300, and the associated milling, if I can avoid it.

    Worth a try, or is this more likely to turn into a waste of time and materials? Given that the steel is only 1/4" thick, is there a risk of adding mechanical resonance?

    Another question that occurred to me was what the effect of the spoilboard weight might have. I'm waffling on the configuration. One is to use a base layer of 3/4" Baltic Birch with 1/2" dados cut in it to fit t-tracks. Then, strips 3/4" thick glue on the Baltic Birch, with the edges of the strips overlapping the edges of the t-track. The other is to put down a Baltic Birch base layer, put on the t-tracks with 1/2 MDF in between the t-tracks, and glue on 3/4 strips of MDF on top, with the edges of the strips overlapping the edges of the t-tracks. If this description doesn't make a lot of sense, take at look at this video.



    I used the second option on my first machine and it worked wonderfully. Take a look at CNC Nutz video, "Don't Spoil Your Spoilboard," and you can see how to avoid having to replace the spoilboard, or greatly extend its life. I use a Makers Guide to zero all of my working coordinates, taking great pains to set the Z offset perfectly. When I zeroed the Z axis to the spoilboard, I never cut into it, except when I had a mechanical issue (slipping) with my Z axis.

    Anyway, I may wait on anchoring and bracing, until I find out what difference the spoilboard makes, if any. Option 2 would add about 140# of additional weight (64# Baltic + 25# 1/2" MDF + 50# 3/4" MDF). It's a step I have to take in any event, so no harm in seeing what effect it may have. Maybe I get lucky and the additional weight does the trick. Not holding my breath, though.

    Gary


  19. #199
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    Re: GME's New 80/20 CNC Build - My Design

    I used 5 Ply birch .500 for the base and then overlaid .750 best grade of MDF. It was special order both pieces because I wanted the full 5 ft wide. The tracks are spaced 8 inches on center but should have been 6 inch. The 5 ply holds the sheet metal flat head track screws better than straight MDF. The stack measures 1.260 as the MDF was metric. Your steel would need to be either angle or square tube to be an effective brace.
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    Retired Master Electrician, HVAC/R Commercial. FLA Saturn 2 4x4 CNC Router Mach4 Kimber 1911 45ACP

  20. #200
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    Re: GME's New 80/20 CNC Build - My Design

    Quote Originally Posted by wmgeorge View Post
    I used 5 Ply birch .500 for the base and then overlaid .750 best grade of MDF. It was special order both pieces because I wanted the full 5 ft wide. The tracks are spaced 8 inches on center but should have been 6 inch. The 5 ply holds the sheet metal flat head track screws better than straight MDF. The stack measures 1.260 as the MDF was metric. Your steel would need to be either angle or square tube to be an effective brace.

    Thanks, Bill. I like Passuello's spoilboard technique better, although there are pluses and minuses. With his, the function of the t-track is not dependent upon screws holding. In fact, you really don't need screws at all. If you haven't looked at the video, you might want to. You end up with a thicker spoilboard, though. Were I to use 1/2" Baltic as the base layer, I'd end up with a total thickness of 1.75". 2" if I used 3/4 for the base and for the top. I have about 10" gantry clearance, exclusive of the spoilboard vs. the Saturn2's 7.4". So, I guess I can afford to lose an extra 1/2"-3/4" in Z axis work area. I went with the extra Z work area by design. I wanted a little more room to accommodate a thicker spoilboard, and give more clearance if/when I decide to add a rotary axis.

    I'm not really interested in a full width piece (my machine is 68" on the inside measure), since my cutting envelope is only 52" x 52". However, I am going to add thin filler strips to close the gaps on each horizontal side of the cutting envelope for dust containment. I'll probably use 1/4" ply, or some .080" 6061 aluminum sheet I have on hand. I have the aluminum in 4' x 12' sheets I purchased from Boeing Surplus probably 30+ years ago. I am also going to add verticals in ply or aluminum that go from the bed to just under the bottom of the gantry - again, for dust containment. For the verticals, I'll just mount the ply or aluminum to some aluminum angle and screw in the extrusion slots with some roll-in t-nuts. I have a Kent CNC dust shoe and a cyclone dust collector, but for some small things, I don't always bother with the dust collector. Less of a mess, if I can keep the dust contained some.

    I understand about the steel. Flat bar is susceptible to flex. Rethinking it a bit, I suppose I could come up with something similar to what's used in the Saturn2's stand. steel plates screwed to the legs and also screwed to tubing. I could use steel or aluminum tubing, or I could use extrusions. I prefer tubing to angle, but, as you pointed out, angle is also an option. I'm thinking some generic aluminum tubing might do the trick and be way cheaper than 80/20. I also have some 1/4" aluminum sheet stored away. I suppose I could cut it into brackets, instead of using steel. More mill work, but that's why I have the mill. I guess I could also use my CNC to cut out the parts. I never did a lot of aluminum on my first CNC, but maybe it makes sense to do some experimenting with this one. The CNC wouldn't be more accurate than my mill, but it would be a whole lot faster. A lot to think about . . . .

    On the issue of t-track spacing, I too went with 8" on my first machine and completely agree that it needed to be closer. I have some outrageously large hold downs just to accommodate it. 6" is better, but I'm thinking 4" O.C. I'll have to toy with both spacings to convince myself which will have more day-to-day utility.

    The spoilboard is next. I just placed an order for some t-track from Orange Aluminum, so it will be a few days. Hard to believe they sell 4' lengths of anodized for just $8.54 each and free shipping on a $100 order. They also sell 8' pieces for exactly twice the 4' cost. I use Orange Aluminum's t-track for other things, and especially like it because it works with Festool's ridiculously expensive screw and ratchet clamps. Most t-track doesn't.

    Gary

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