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Thread: bolt frame build

  1. #41
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    Default Re: bolt frame build

    Quote Originally Posted by mactec54 View Post
    Are you saying someone should try the Urethane Foam from your link, it would help with dampening but would not change rigidity of the extrusion very much, where as the EG will do both but adds a lot of weight
    i am going to have to agree with this point over foam filling. i never intended to have E.G. be the main structure of the build but wanted to gain the dampening and stiffness gains from and assist to the steel frame work. extra weight is a good thing when it comes to machines in general.E,G. is nice because you can do it pretty much anywhere and nothing special is required for the most part.



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    Default Re: bolt frame build

    Quote Originally Posted by peteeng View Post
    Hi MD - Construction extrusion is particularly inefficient in torsion vs its envelope. So by tying all those webs together its a big help. Just want to point out that those thinking about doing this sort of thing it maybe easier (and cheaper) and better to use a large std extrusion or steel section for a gantry vs construction extrusion. Choosing things for convenience often does not hold the best solution down the track

    For instance if you place some epoxy on an extrusion and let it cure you will easily be able to flick it off some time in the future. So filled voids will eventually decouple from the structure IMHO. On the other hand foamed PU sticks like the proverbial stuff and will not decouple... These things have to do with surface smoothness and moisture. Extrusions are very smooth (in terms for bonding things to it) and its difficult to prepare inside of voids. PU is moisture tolerant vs epoxy which is not and surfaces have moisture on them creating a barrier to sticking. Having said that many many people do this and are happy and I'm all for people being happy... Peter
    i think you have to look at the shape of what your filling. the t slot shape locks the E.G in place so unless the cast busts up it's not coming out of the extrusion. the shrinkage is .001 so if the cast pulls away from the walls it;s not a big deal as long as it stays intact. you can't twist or flex still because you took the space to move out of the picture. i'm not here to say one way or the other that this is the best thing since sliced bread. build at your own risk i'm not here to mass produce this machine or sell parts of it this is just a log of my build and things i encounter along the way.

    for instance the ball screw whip not one comment on the solution i came up with but all the interest in the E.G. fill that has been done for a while now



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    Default Re: bolt frame build

    Hi MD - your whip solution is very good and I don't want to hog or sidetrack your blog. EG has millions of entries in this forum. Its a huge topic. Your machine will be good. I get a bit myopic on some topics. Better breath and get back to my machine Peter



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    Default Re: bolt frame build

    Quote Originally Posted by peteeng View Post
    Hi MD - your whip solution is very good and I don't want to hog or sidetrack your blog. EG has millions of entries in this forum. Its a huge topic. Your machine will be good. I get a bit myopic on some topics. Better breath and get back to my machine Peter
    i don't mind feed back good or bad thanks. the spring load guides work really well to contain whip by the way. the drive beam being able to pass under it was the hard part but it does what i need it to do and works so that's all that counts. now if i can get my traverse speed up some i would be happy my gearing has me at the moment and i have some parts coming to change that part.



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    Default Re: bolt frame build

    kinda looks like i will have some extra time to work on things. looks like a state wide shut down of non life sustaining business for a while my daughter was just telling me. super flu strikes again by the looks of things.



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    Default Re: bolt frame build

    Hey there machinedude, just reading through your build and love the pics. I am just beginning a build on my 4th machine. Your issue with flex in the bridge is something I ran into on my second machine. It’s structure was similar to yours although shorter in length. I at certain feeds and speeds, I had chatter due to flex in the bridge. It was only an issue when the head was near the center of the bridge. My fix was... adding a “torque tube” to the back side of the bridge. I had some 1/4” wall 2 1/2” OD aluminum tubing standing in the corner of the shop. I cut 5 brackets out of some 1/2” aluminum plate about 4” square and bored 2 1/2” holes in the center. Drilled two mount/clamp holes through the 4 inch length of 2 edges of each piece. Lots of drill clear the chips, drill, clear the chips..... then cut the pieces in half making each clamp 2 C shapes so that 4 1/2” bolts would pull them together around the tube and run into the T nuts in the extrusion slots. The tube was about an inch shorter than the bridge extrusion. I put one bracket at each end of the tube, one in the middle, and the other 2 half way in between. Or 5 equally spaced brackets clamping the torque tube. Only way for the extrusion to twist was for the tube to twist. Sort of like trying to twist a drive shaft tube. Hope my explanation was clearer than mud. I’m on an iPad or I would sketch it for you. I don’t have that machine anymore, sold it to a friend a few years back before retiring and moving to Mexico.

    Steve
    Trapped on a small Caribbean island



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    Default Re: bolt frame build

    Quote Originally Posted by vger View Post
    Hey there machinedude, just reading through your build and love the pics. I am just beginning a build on my 4th machine. Your issue with flex in the bridge is something I ran into on my second machine. It’s structure was similar to yours although shorter in length. I at certain feeds and speeds, I had chatter due to flex in the bridge. It was only an issue when the head was near the center of the bridge. My fix was... adding a “torque tube” to the back side of the bridge. I had some 1/4” wall 2 1/2” OD aluminum tubing standing in the corner of the shop. I cut 5 brackets out of some 1/2” aluminum plate about 4” square and bored 2 1/2” holes in the center. Drilled two mount/clamp holes through the 4 inch length of 2 edges of each piece. Lots of drill clear the chips, drill, clear the chips..... then cut the pieces in half making each clamp 2 C shapes so that 4 1/2” bolts would pull them together around the tube and run into the T nuts in the extrusion slots. The tube was about an inch shorter than the bridge extrusion. I put one bracket at each end of the tube, one in the middle, and the other 2 half way in between. Or 5 equally spaced brackets clamping the torque tube. Only way for the extrusion to twist was for the tube to twist. Sort of like trying to twist a drive shaft tube. Hope my explanation was clearer than mud. I’m on an iPad or I would sketch it for you. I don’t have that machine anymore, sold it to a friend a few years back before retiring and moving to Mexico.

    Steve
    Trapped on a small Caribbean island
    when i was testing the ball screw was not attached to anything at that time. the way i have my gantry built is with the ball screw and bearing blocks mounted on the back side of the extrusion. the bearing blocks are mounted to .750 thick x 1.5 wide aluminum flat bar that is as wide as the extrusion. so the ends of the gantry beam has some extra support because of those on the ends.twist is no more than .005 now so it's pretty solid at this point. to be honest since the gantry is mounted to the frame i could be picking up so movement on the indicator from some table flexing? so when i do the E.G on the Frame i think those number will shrink some. it's a work in progress. this is by far the biggest machine frame i have ever done so it's a learning experience no doubt.

    i could probably add a piece of flat or angle to the back of the uprights and get some more rigidity but that can wait until i see how it does as it sits. i'm thinking like it's a commercial VMC in my thoughts of how solid it should be but the small spindle i have on it now is not going to be like that obviously



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    Default Re: bolt frame build

    I had a bit of time so I searched back through my posts and found a pic of what I described.
    bolt frame build-323b6002-26b9-4060-afbb-4b724c0c9669-jpeg

    Like my linear rails on that one? The tube and clamps on the back is what I was explaining.



  9. #49
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    Default Re: bolt frame build

    Quote Originally Posted by vger View Post
    I had a bit of time so I searched back through my posts and found a pic of what I described.
    bolt frame build-323b6002-26b9-4060-afbb-4b724c0c9669-jpeg

    Like my linear rails on that one? The tube and clamps on the back is what I was explaining.
    back in the day you would see a ton of skate bearing linear way set ups kids these days have it made with cheap linear rail prices you see today the way i have my frame built i can't get much attached to the back side with a ball screw back there. so the end mounts for my bearing blocks for the ball screw are going to be the extent of support on the gantry cross beam. i'm not going to get to excited till i see how what i have does. it's pretty solid but as is but it's hard to tell until you start cutting and get a clear picture on how everything does.



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    Default Re: bolt frame build

    If you want to do a little investigation and you have an iPhone, there is an app called “vibration”

    bolt frame build-204e2268-653f-47c8-8db5-fc225983b8b6-jpg

    Attach your phone to the lower end of your z axis, run the app, touch sample and then tap the lower end of the z in the y direction. When sampling is done, touch the frequency display icon and you can see what if any the resonant frequency of your gantry is.

    Steve



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    Default Re: bolt frame build

    honestly i think you pick up vibration off the entire frame and not just the gantry. i spent some time making a rough model of my table so i can work on how to build forms around everything so i can do E.G. on the table and frame work. so until that part is done overall performance is something that is up in the air still. i have 12 gallons of epoxy and 2 gallons of harder so i have a lot of casting to do yet. then i have to get to the actual table top. the plan is to do a 1" thick t slot top in aluminum. so needless to say i have a ways to go on this project.



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    Default Re: bolt frame build

    i think when i am done i should end up pretty close to looking something like this on my table. the basic idea is to use the E.G. to stiffen and dampen vibrations and use the frame work in place now as a preset rebar. the table under the T slot top is pretty much filled except for a 9 inch wide section down the center that will be needed clearance for the ball screw and drive about 3/4 deep in that part of the table frame. i will have to box in around the ball screw guides but will basically make the frame into one solid piece.

    bolt frame build-screenshot-177-png



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    Default Re: bolt frame build

    got some more work done on this build. I've had the drag chain for a while but just now got to putting some of it on. turned out to take a bit longer than i thought. once i got into it i now see why every one adds some kind of support under them. i almost did not get it mounted because i thought i was out of anything long enough to make a support out of until i seen a length of frame material i had sitting in the corner was able to make something that does the job and did not have to buy something so i am a happy camper as a result

    bolt frame build-0328201726-jpgbolt frame build-0328201725-jpgbolt frame build-0328201724-jpg



  14. #54
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    Default Re: bolt frame build

    hopefully a short video of things working for some reason this site gives me grief when it comes to video?






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    Default Re: bolt frame build

    Looking good! Drag chain support works great. I’ll probably do something similar with the drag chain, only needs periodic support. Access to heavy aluminum stock around here is pretty scarce. About the only source is at Grainger, and have to order, wait then pay $$$! I brought quite a bit of extrusion with me when we moved so framework is covered. I did buy one 6 ft piece of 1/2 by 4 inch aluminum bar from Grainger... price was $2,059 MX (about $100 US) !!!

    My Z axis will be a bit different from yours. The linear rails will move vertically with the bearing blocks mounted to the X carriage on the bridge. I figure this will add a bit of rigidity to the Z when it is extended down.

    Is your spindle motor from an older mini mill? Looks like you have step pulleys for speed range adjust. At some point I will get a water cooled 2.2 KW spindle and controller so it runs quieter than the screaming Bosch Colt.

    Hope you are staying safe and healthy during this time. Zero cases here so far, fingers crossed.

    Steve
    Trapped on a small Caribbean island
    Little video I made a few years back





  16. #56
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    Default Re: bolt frame build

    yeah that spindle is off a grizzly lathe mill combo. it's a 4/5 HP spindle and the belt drive is a kit from little machine shop. high and low range on the pulley's. i think the original was driven with plastic gears? at the time i had no space for anything to big and the machine was in the basement of my house lack of travel for milling was the turn off for me. i picked up a Bridgeport mill from a shop i worked at that they were getting rid of for $250 so i had no need for the milling end of that machine. i did have the head on a t slot frame a while ago but was never happy with it because it was way to light for milling it only did ok after i put 2 double 6" vises on the table for more weight so many years later here i am back at this idea



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    Default Re: bolt frame build

    Quote Originally Posted by vger View Post

    Hope you are staying safe and healthy during this time. Zero cases here so far, fingers crossed.

    Steve
    Trapped on a small Caribbean island
    Little video I made a few years back
    Pennsylvania is getting locked up county by county. they county i live in has a stay at home order in effect right now but i still get to go to work since we supply medical related parts to manufactures. so i guess i have an important enough job to keep working. i'm not sure if that's a good or bad thing honestly? i have never seen anything like this in my life time so you take it one day at a time i guess.



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    Default Re: bolt frame build

    i did manage to get the drag chain hooked up along the side and get power to the spindle. i rigged up a make shift set up for spindle control as well. i have to go over the spindle belt alignment but should be cutting some plastic at least for some E.G forms this weekend. i don't plan on pushing this thing very hard until i see if everything works as it should but should at least be cutting something. the plastic sheet is not supper expensive material but expensive enough that i would rather not waste material because i got in a hurry it still costs $80 a sheet. i figured it would work well for mold form material since the release should be easy with it.



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    Default Re: bolt frame build

    i had to button up a few small things on the spindle. did some axis calibration and mounted a mister i had for this build. found the plastic tank at the dollar store the back of the z axis looks like a good place for it to hitch a ride on the gantry. i still have to figure out a way to secure it in place. i routed a platic air line trough the drag chain and will make a manifold to transition between the plastic air line and a ball valve to have a basic manual control for the air. nothing fancy just functional

    bolt frame build-0403201632-jpg

    bolt frame build-0403201632a-jpg

    bolt frame build-0403201631b-jpg



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    Default Re: bolt frame build

    i have seen a few people who always ask what to use in a mist coolant system? well over the years every shop i have worked at has always used this stuff. Kool mist 77 is what i will use. 1 gallon of coolant costs around $40 but it gets mixed with water and only takes 4 oz. per gallon. so you get 32 gallons of mist coolant for $40.

    bolt frame build-kool-mist-jpg



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