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  1. #81
    Join Date
    Apr 2007
    Posts
    273

    Re: bolt frame build

    yeah i can't say i remember it getting really warm on me with the limited stuff I've done with it. but after it got brought up i'm sure i will pay closer attention to if if the weekend ever gets here this week is off to a slow start already.

    i think i might switch out these steppers for DMM servo's i have if all goes well with the mold. i will give it a test when the time comes to start working on the final table top in aluminum. that will give me a lot of serious cutting to play around with. if the frame does well i want to do a dual loop feedback with linear encoders if i can figure it out. Linux cnc is how i would like to go with the aid of some Mesa hardware. i might even upgrade the spindle motor with a servo to have control over it in the software. that's not to bad to do with the drive set to analog and using the 0-10V for a signal.

    after the molding is done i can fine tune the table top for flatness so i don't have to skim much off the aluminum. i want to keep as much thickness as i can for t slots and a 1" thick top is not going to be cheap so i want to get the most out of it so i have something substantial to clamp to.since i have a milling spindle i can cut things flat with the machine with the reach of the machine. the way things are it would not be to bad since the center area is the high section for the most part. the width of the frame was pretty close but the long axis needs some fine tuning. so needless to say building something this big on a manual Bridgeport machine has been not so easy. the gantry was not to bad but the table has been a pain in the butt.

  2. #82
    Join Date
    Apr 2007
    Posts
    273

    Re: bolt frame build

    well i did not notice any heat being generated from the chemical reaction between the resin and hardener so it would seem this is not to much of an issue with epoxy granite.

    but the mold i built takes more material than i thought so needless to say i need more supplies to finish the job. i under estimated how long it would take to work through a mold this size no doubt. i can honestly say i would never want to do a project this size again. working by yourself mixing this much material by hand is no fun.on a project this size you have to just take your time packing and tamping the material in tight as you go.

    you literally have the place where you stated dry and set at the end of the day while the place yo finished up being wet. so when you end the day you have to terminate in a good place. if i was counting on this being the main structure i would most likely rethink the planning but that's not the case with how i built this machine. so my case is a little more forgiving in this sense.

    what i have so far i like a lot and i have no doubts about it doing what i want it to to but this is not going to be a cheap add on by any means. as of now i have a little over 1000 lbs of E.G on the machine and i think it will take another 1000 lbs since that did not even get to the table top. so in total i am looking at like 22 gallons of epoxy for this project to get it done.

  3. #83
    Join Date
    Apr 2007
    Posts
    273

    Re: bolt frame build

    the mold worked pretty good so here is what i am looking at as of now. i plan on painting the machine so some body work will be needed to get a surface worth painting but that's not a big deal. i picked up some industrial enamel made by PPG paints already for this.

    Attachment 442332

  4. #84
    Join Date
    Apr 2007
    Posts
    273

    Re: bolt frame build

    i think the supplier of epoxy i use needs to work on their methods for tracking shipping i was starting to get worried about not having stuff to do this weekend because i was waiting on the epoxy and since it was Thursday and i did not see it i started to see if i could find out when it shipped. i came across an e-mail today saying it shipped today and was like great i doubt i have it by the weekend. but when i looked the tacking number up they said it was delivered today. turns out they had it sitting in the driveway where i could not see it. but still does not explain the delayed tracking number and shipping notification i just got today saying it was shipped today

    round two at this thing this weekend

  5. #85
    Join Date
    Apr 2007
    Posts
    273

    Re: bolt frame build

    i did manage to order some magnetic scales and reader heads for this project. was a bit of a challenge getting past the language barrier translators seem to complicate things but at least the dual loop feedback quest in on track for when that part comes

  6. #86
    Join Date
    Apr 2007
    Posts
    273

    Re: bolt frame build

    just an update with this project since this summer was rough as far as free time goes. too many other things going on to have free time to work on this project. but i have been back at it lately and made a little bit of progress.

    after casting E.G. in the frame i got myself into some finishing work before i could paint the frame. i got to the point where i was like good enough. not perfect but not horrible either

    i had material coming today and it was probably was a waste of time to set the slats on the bed of the machine but i wanted to see it on there to see the final heights of things so i took the time to do so anyways starting to look almost finished starting being the key word here it's going to take a while to turn these into a t slot top. lots of machining since they are 55 inch long by 12 inches wide and i have 10 of them to do.

    now comes the fun part getting things flat on such a big surface after that some final trim pieces and probably some chip guards for the linear scales once i get to that point. i still have a ton of work to get done.

  7. #87
    Join Date
    Sep 2020
    Posts
    81

    Re: bolt frame build

    Beautiful it looks. the long shiny aluminum plate. Big long router fascinates me. May be someday I will build one too once I have enough experience and space available.

    I visit this forum, read people opinion & experience but missed this thread.

    Looking forward to this build now.

  8. #88
    Join Date
    Apr 2007
    Posts
    273

    Re: bolt frame build

    Thanks Rupesh, big machines are nice but can be a pain to make with limited equipment.so sometimes you have to think outside of the box and do things based on what you have to work with. you always learn something new with these projects and for me i have had to adapt lots of things to get them working well. i'm pretty happy with the frame so far it's about as solid as you can get i think. i set an indicator on the bed of the machine and set everything in the middle of the table and got up on the table and had zero movement on the indictor with my 200lbs of body weight so i have a decent base to work from. i did some test cuts in aluminum before casing the E.G. into the frame and the tests went pretty good but the skeleton frame work was where the vibration started beyond 2mm DOC on the side of the cutter with a 3/8 endmill slightly over 3/8 deep. the spindle i have does not have a ton of power so i think 3mm is about all i can get with a .8 HP spindle motor. the spindle is actually a mini mill head and is probably doing better than the original machine it was on.

  9. #89
    Join Date
    Apr 2007
    Posts
    273

    Re: bolt frame build

    this is not really the best test for cutting steel since the work holding is anything but ideal for what i am doing but i will say if the insert is sharp and with the right finishing strategy a more than acceptable surface finish can be had with what i have built. so if i can get this kind of result with hot rolled steel which is not the best material to begin with i think any Aluminum work should be pretty easy it get some pretty good results.

    it's getting closer to being flat it just takes some time and effort to get there. with the fly cutter i am using i should be able to swing a big enough diameter cut to reach out beyond the travel to machine 90% of the table surface. i have about 19 inch on the back side i can't reach with the machine. that part i can basically do by hand with a indicator and some strategic grinding and draw filing the surface area of the mounting surfaces are not that big so it should not be to bad to finish the last little bit by hand

    once i get the base pretty close i can start drilling and tapping mounting holes for the aluminum table top and start on dialing in the precision a bit more by tramming the head in and do a final surfacing on the aluminum top. the plan is to get the base as close as i can so i don't take any more than needed from the surface of the table top.

  10. #90
    Join Date
    Jul 2018
    Posts
    6249

    Re: bolt frame build

    Hi MD - So your going to bring the "ribs" down to the epoxy fill height? or is the table going to have air above the epoxy fill? How thick are the slats? and Rupesh your sounding like Yoda! (Beautiful it looks. the long shiny aluminum plate) Keep at it, both of you or You both, at it keep...Peter

  11. #91
    Join Date
    Apr 2007
    Posts
    273

    Re: bolt frame build

    i'm just skimming the top Peter i wanted to be the E.G. part way up on the fill but its just to the base of the metal so it's supported under the metal as it sits now. things worked out differently than planned but i will say i think that the vibration dampening does have a lot to do with surface finish.

    i'm not saying this is a machine to cut steel. it can do some stuff within it's limits. a single point cutting tool with a 2" diameter swing or better is a lot to ask of a single insert so while it is sharp it does ok. once the top is added i am sure that will help some as well it is 1" thick so that will add up to a more substantial work surface too.

  12. #92
    Join Date
    Apr 2007
    Posts
    273

    Re: bolt frame build

    the steel under is 3/4 thick everything else is basically one piece since doing the casting. the E.G steel skeleton under that 3/4 top rib is close to 2" thick. it's solid no doubt. i think the entire machine with the Aluminum top will be about 4,250 lbs to 4,500 lbs so it's over 2 ton when finished.

    milling things flat to the gantry is make it close i think i can get the surface that way flat within .001 to .002 imperial.

  13. #93
    Join Date
    Apr 2007
    Posts
    273

    Re: bolt frame build

    been picking away at this thing and sorting some issues out along the way but have things moving forward again at least. i had some issues with the speed control for the mini mill head i am using so i changed the motor and control. i had an old tread mill that was kind enough to donate some parts at first i got excited about the new motor because the ID plate had it rated at 7,100 RPM and the old motor was only rated at 6,000 but in reality it was only about a 400 RPM gain but the torque gain was 3 times greater so i was able to do away with the step pulley and use just the high range. in the modification the low range pulley got lost due to a bigger shaft on the 2.5 HP treadmill motor. but the HP rating on these motors are over rated since the control of the MC 60 Board used operates on 90V so you end up somewhere between 1 and 1.5 HP. my best guess is i have about 4.600 RPM for a top speed on the spindle. lower speeds with these types of boards are limited since you don't get the most torque unless it is running wide open. but cutting Aluminum as a primary use was what i was looking for and it does that pretty well for what the spindle is.

    i started slotting the Aluminum flats for my table top so i can make a t slot table top and am using a 3 flute 5/16 carbide end mill for this. i pushed it to the brink and beyond to see what i could get and ,120 deep at 40 IPM the cutter snapped at 30 IMP you can start to hear it coming but did good at 25 IMP. i backed it off just a little to be safe and ran it at .100 deep per pass at 20 IPM and zero issues there running 4 slots through the 12 inch x 55 inch long sections. the biggest issue is keeping the chips out of the slots once your deeper in the slot.

    made a sort video of the cutting with a 5/16 endmill going .100 deep at 20 IPM in 6061 to show my results so far.


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