Pcnc conversions, upgrades & rebuilds


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    Default Pcnc conversions, upgrades & rebuilds

    Thought it might be good to get all the custom work being done to these units in a single thread for all Pcnc owners. There are some who have done a great job in making their machines function like they originally should have.

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    Default Linear bearing and ball screw conversion part 1.

    Wow
    Where do I start ? except back in late last year when I believe I was next to if not the last to receive a machine from Bill.
    My college and I thought that the machine had enough merit to keep it and do the conversions necessary for good tight machining.

    The first step I took was to get the headstock as rigid as possible without rebuilding the whole thing as I see (bdsorcic) has done and done fantastic.
    We thought the wisecarver bearings should still be tried as they look like they might hold up well enough.
    I decided to build an internal skeleton framework out of simple off the shelf aluminum angle. By tying the Z axis to the Y axis and the two steppers together thus eliminating the slop that was present.
    Below are pics of the head assembly with that upgrade.
    Pcnc conversions, upgrades & rebuilds-img_00421-jpgPcnc conversions, upgrades & rebuilds-img_00411-jpgPcnc conversions, upgrades & rebuilds-img_00431-jpg

    Due to file size restrictions I'll end here and go to part 2. of our upgrade.

    I also took the time here to rotate one of the Z axis bearings 90 degrees.
    This gave the Z axis better strength in the two dimensions of travel. The wisecarver bearings are best if used parallel to the axle line and not 90 degrees across it. At this point I also kept the acme screw that came with the unit even though it looked to small. My last fix for using the original headstock was to ad a single linear bearing to the bottom of the y axis as this would take up most of the load while machining.
    I decided this last fix after pricing linear bearing$ As this prevented me from redoing the whole machine. But finally after looking on ebay, a seller by the name "irvineman" had very good quality linear bearings components at screaming good prices. I had one unit that had to be replaced and they took care of me pronto!
    Sooo, I then decided to redo the entire machine in linear bearings along with a ball screw for the Z axis as the cost for the components came in I believe just under $800.00 I could live with this.
    Irvineman had some combination specials that included the 2 open bearings, bearing housing, rod and extruded support rail all for one great price, still $159.00 with free ship, You can't beat that anywhere.
    I decided on 20mm for the X axis and 16mm for the Y and Z.
    One of the 16mm shaft combos was long enough for me to cut about 11" of the end to use for the Z so it was a freebee.
    The X axis 20mm shaft combo from irvineman was 55" long so I decided to keep the extra length and extend the reach of my router to about 45".Pcnc conversions, upgrades & rebuilds-img_01521-jpg Pcnc conversions, upgrades & rebuilds-img_01141-jpg
    I also decided to go with a 5/8" ball screw assembly for the Z
    Pcnc conversions, upgrades & rebuilds-img_01081-jpg
    Now all axis run on linear bearings. As an added note The linear bearing components are of regular hardened steel and not stainless.



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    Default Linear bearing and ball screw conversion part 2.

    Now with all the linear bearings in place you probably noticed a new head stock much like bdsorcic. I took the short cut and used 1/4" thick 6" wide shelf stock to replicate the original head stock without any milling. But now my head assembly is 6" wide and this was designed to accommodate the added gear reduction to the stepper drive. I used the same belt pitch to get the resolution of the stepper down even further so that we could run the steppers closer to full step but not quite as the resonance started to interfere. After contacting Kelling who made the steppers we found that the best torque ratio was to get them as close to full step as possible, they mentioned that torque falls off when you got to smaller step increments. So I designed in A 60 tooth sprocket to each stepper in both X and Y. This gave us almost the same resolution as before except the we are now at the power of full step .0016 per step. However as I noted before that resonance will cause problems with running at full step so I went to 1/2 half step and found this to be satisfactory.
    Below is the reduction drive in the head assembly
    Pcnc conversions, upgrades & rebuilds-img_00551-jpg
    Below is the reduction drive in one of the uprights in the X gantry.
    Pcnc conversions, upgrades & rebuilds-img_01001-jpg
    Now with all the wiring in place
    Pcnc conversions, upgrades & rebuilds-img_01041-jpg
    You can also see the I replaced the original audio wire that Bill used for real flexible machine control cable made by IGUS they also made the cable chain that Bill used , But now I can see why he opted for the cheaper route as the "chainflex" cable by IGUS is costly, but worth it if you are going to build in longevity. All the reduction sprockets run on ball bearings set in pillow blocks that I made from aluminum. I replaced the rubber XML belt on the X as they were now too short with polyurethane belts which hold up better.



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    Interesting. I wonder if there is some middle ground to beefing it up without having to re-engineer everything. Thanks for showing us this.



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    This is a great new thread showing what is being done with what might have been.

    Unfortunately (or in hind sight fortunately) I never received my router from the infamous BJ so I'll just watch this forum to see how you guys are making out.

    FWIW, I have received my new router (yea, my deal in life was to pay for two routers and got one). I got the very first CAMaster Stinger and will be up and running shortly. Boy, you guys need to look at the construction of this Stinger, it's built like a tank (and weighs 300 pounds without a stand). You can see pictures at www.stingercnc.com to see how a gantry should be made.

    Good luck,

    Dennis



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    Thumbs up Great Thread

    Wow, Some of you are really doing a great job improving your machines. That CamMaster Stinger is what I call a "Machine" It is like comparing a VW to a Rolls Royce! Wish I had the money for such a great machine like the Stinger ~
    protrackcorp, excellent job ! You have done a great job your improvements are something I am pounding over but as a retired guy I need to go out and make some more money for that first Ha-Ha!



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    By the way, not exactly sure how this could help any of those who have routers from BJ, but his sister (who got stiffed as bad or worse than the rest of us) has a garage full of stuff? What kind of stuff - well whatever Bill had when he took a powder and left all of us who had paid for routers with nothing to show for our money. FYI, according to his sister, he had the pad poured for that pole barn of his on his sister's land and never paid the contractor. So she's had a lien placed on her property by the contractor.

    OK, so where am I going with this on this thread? Well, to get back on topic, if anyone who has gotten a router needs any spare or replacement parts, they may be in her garage and she needs the money so if you could identify the part she may be able to find it and sell it to you.

    I'd rather not publish her contact info on the forum since she's already been felt the brunt of her brother's deceit via calls, messages and visits, but if you PM me I'll give you her e-mail address.

    Hope this helps someone. Personally, I like the idea of having Bill's stuff sold on him. At least he's not benefiting from what he bought with my money.

    Dennis



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    Making mods to my machine. Nothing new in design work, I've simply purchased the headstock that protrackcorp modified and documented earlier in this thread and installed it on my router.

    Had to do some serious tweaking to get it installed. Must have spent a couple of hours getting the wisecarver bearings adjusted just right. Adding a washer here and there and fiddling with the center wheel tension.

    Anyhow, the new (to me) headstock is on and all the function tests have past, still need to try an accuracy test to see if I've improved anything.

    Next on my list is to lengthen my table space by simply replacing the side rails with longer ones. I'm already planning to rework the table surface because of some underlying unevenness, so this would make a nice improvement project.

    Attached Thumbnails Attached Thumbnails Pcnc conversions, upgrades & rebuilds-dsc_0001sm-jpg   Pcnc conversions, upgrades & rebuilds-dsc_0004sm-jpg   Pcnc conversions, upgrades & rebuilds-dsc_0006sm-jpg  


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    Well I'm starting to think about building my own machine again. The ol wisecarver bearings really suck in my application. I may end up building something with a smaller footprint as I don't need this size I'm finding out. I'm thinking about leadscrews for the simplicity. Speed is not as important as accuracy and I was pretty happy with the speed of my homebuilt #1. Anybody know of a good link for screws with anti backlash nuts that have prices included?



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    Hi luthier,
    Whatcha going to build? any specific model in mind? My Machine was doing fine till my hard drive decided to crash, Ugh!!
    Seems like the new aluminum head and the addition of the third rail did the trick for me, and it has been doing well.... but I have not carved enough yet to be exact sure if it is worth its weight in salt! I have put the machine under cover for the summer and I am enjoying the summer family vacations and am not going to worry about againit till the cold winter months.



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    Nothing fancy really, I would buy the supported rails like VXB sells or a similar vendor and machine some end plates out of aluminum. I did my original one out of HDPE, angle aluminum, roller skate bearings, and drill rod and it was a better machine than the pcnc in terms of accuracy. Anti backlash screws and supported rails would be much better. I have motors and controllers here so the only thing is materials need to be procured.
    Marty



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    One thing I noticed yesterday is that the Z axis has play up and down. It has a bearing of some kind towards the top but nothing to hold the screw in place. This is because it has the belt drive instead of the motor mounted on top. I'm thinking of putting some type of brass fitting over it to ride on the top of the threaded rod and see if that helps the slop.



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    I decided to purchase a K2 Z axis assembly from Ebay. Now I am in a situation where I either remanufacture the head assembly or just start from the ground up again with my own custom build. I also bought some used 24 "THK linear guides. They are really clean, but it seems they don't move as easily as I imagined. The thing is that they are about the same thickness as the wisecarvers. The hole locations are different though and some fiddling would be in the works. They require more force than I thought they would too. Maybe I'll check out some Glacerns. I'm beginning to wonder if it will be worth it to retrofit the parts onto the pcnc.



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    Luthier, if you do retrofit the parts, please post some pictures on here. I, for one, would be very interested in seeing what improvements are possible on the PCNC.

    My current project involves keeping an eye on eBay for some affordable 80/20 rails, around the 6' length. I figure that to expand the tabletop from 2x3 to 2x5 should be fairly simple. Although if someone has some advise on redoing the wiring, I'd be happy to hear it.

    Also, does anyone know where to find those rubber belts used for the rack-n-penion system? I'm going to need new ones when I expand the tabletop. I'm not even sure what the correct name is for them to use for a Google search.

    Update: I did my tabletop leveling. Pulled all the MDF spoilboard off, (originally stuck on by Bill with double-sided tape), there was about 1/32" of surface sticking up above the metal T-Slot rails. I used a 1.5" flat mill to level the tabletop even with the overhead gantry. Decided against putting a spoilboard back on, figure I'll just use scrap under a project when needed.

    Last edited by SparksStudios; 10-09-2010 at 10:10 AM. Reason: spelling


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    I was wondering if those "soft" racks were just belts cut open? I think they are available at McMaster-Carr or MSCindustrial.



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    Well, I've discovered something that might be obvious to others but took me a while to work around.

    I tried to blame Bill for the sloppy output of the PCnC machine, (and Lord knows there are all kinds of cheap construction in it!) But I have finally determined that all the lost steps and misalignment errors I was experiencing was due primarily to the under-powered PC I was using.

    I had problems with smaller projects but could never see enough of the error to nail down what has happening. Then I tried a really big job, a file of the Mayan calendar, (misnamed Aztec, but available on this forum here: )

    Vectric Forum • View topic - "BIG" Job....

    The file produced a toolpath over 210,000 lines long! I've cut this file 3 times now. The first two times were an absolute mess, with dropped steps causing gross misalignment errors all over the place.

    So I thought I'd try a hunch and upgrade the old Pentium III PC with it's 500Meg memory running XP to something a little more modern.

    Well, yesterday I tried the calendar file for the 3rd time, and wouldn't you know? No alignment errors!

    It didn't go any faster (still 9 hrs. to cut) but at least everything was in the proper place. So I'm happy to have resolved that.

    Not that there still isn't a bunch of things that need fixin on the PCnC machine.

    Is anyone still using their machine with a unmodified head assembly? I noticed that even though I had the head reinforced to eliminate flex, that the mounting plate that extends down that the router attaches to is still just a flat piece of metal, that flexes like a diving board when extended down and pushing the router along a deep cut in material.

    Maybe I can replace it with something that has a right-angle bend in it for stiffness.

    Progress is slow, but it is getting there.



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    Just so you all can find parts.... those so called "rubber belts" are called Timing Belts and can be purchased at McMaster-Carr in anysize either in circles or plain straight, and the correct size is to fit the PCNC machine is ....... "Trapezoidal-tooth Neoprene Belting, Xl Trade Size, .200" Pitch, 3/8" Width"



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    Quote Originally Posted by bdsorcic View Post
    Just so you all can find parts.... those so called "rubber belts" are called Timing Belts and can be purchased at McMaster-Carr in anysize either in circles or plain straight, and the correct size is to fit the PCNC machine is ....... "Trapezoidal-tooth Neoprene Belting, Xl Trade Size, .200" Pitch, 3/8" Width"
    Perfect! That's what I needed, Thanks bdsorcic!



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    Building guitar parts has come to a standstill. I'm tired of producing bad parts. I was looking at Ebay and noticed that the K2 people had frames on sale. I ended up buying/ordering a 2514 with shafts. I'm hoping it will be a band aid for now and will be more rigid than what I have now in my homebuilt and the pcnc. Now I will procure parts for my next more rigid home build which is what I should have done a year ago. I already have motors and controllers here from a previous open loop build a few years ago. If the K2 works better than the pcnc, I'll sell it off or donate it to my old school.



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    duplicate post



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