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First Design - C Beam Router

Discussion in 'Concepts and Ideas' started by Metalguru, Jan 12, 2016.

  1. Metalguru

    Metalguru Master
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    Hey guys:

    This is my first kick at designing a router based on C-Beam linear actuators.

    I designed a gantry plate which is basically an extended version of the standard C-Beam gantry plate but is larger and adds 4 more wheels on the outside tracks of the C-beam. I figure this will enhance the stability and stiffness of the C-Beam gantries. The same plate is used for both the X and Y gantries. It could also be used on the Z axis gantry plate if necessary. The Z gantry plate will have a router mount bolted to it.

    The Y gantries are loosely based on the Routy gantry arrangement, with a single 80x20 upright. I'm a bit concerned about stiffness here, any ideas to reinforce the X gantry mounting would be welcome.

    Keep in mind this is a rough draft, it's missing a lot of small detail like bolts, elbow brackets, and tee nuts, etc, but the major components are all there.

    Please critique, let me know what you think.
     

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  2. Metalguru

    Metalguru Master
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    Sorry, I just thought I'd supply a picture in case you don't want to load the .SKP file c-beam router.jpg
     
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  3. JustinTime

    JustinTime Master
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    Metalguru, considering how much travel you have on your z axis, that 20x40 lower cross beam on the y will limit the thickness of the material. I'm not sure it adds a lot to the overall rigidity anyway.

    Otherwise I like the design. :thumbsup:
     
  4. Metalguru

    Metalguru Master
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    Hey Justin:

    Yeah, I thought about that too, but the limiting factor is the bottom end of the Z axis c-beam anyway. Unless, I could turn the Z axis around so that the X and Z gantry plates are facing each other and attached together, then the whole Z axis actuator would move up and down. Then simply bolt the router mount to the back of the Z axis c-beam. Hmmm.

    The Z axis c-beam and the 40x20 are just held on with t-nuts anyway, it would be simple to loosen and slide them up for more table clearance anytime you need it. Maybe I could also just go with a 20x20 to give more clearance. I could also make the Y axis vertical 80x20's longer and move the whole x-z gantry up.

    I think the 40x20 is needed to add stiffness to the gantry, I couldn't see any other way to stiffen the assembly.

    I have to also figure out some kind of brackets to assist in mounting the X axis beam to the y gantry uprights. Do you know if the 2 holes on the front side of the end plates on the c-beam are threaded? It doesn't show them as being threaded in the drawings, but it makes no sense to put them there unless they are...
     
  5. Steve Fox

    Steve Fox Veteran
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    I plan on converting my OX to a C-Beam Z-Axis. There is a lot more room than you show under the C-Beam. If you move the router down, there is around six or seven inches, depending on the type of router and type of bit.
    Some of the holes in the front plate are threaded and some aren't. There are plenty of both to suit your design.
     
  6. Metalguru

    Metalguru Master
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    Update

    I did a few mods like substituting the extended gantry plate on the z axis for the stock plate, and adding a router mount. As well, I moved the z axis c-beam and horizontal brace up a bit.

    I now have about 60mm of maximum material thickness. I could make the 40x80 side pieces quite a bit longer. Steve, the side gantry plates on the Ox are quite high, so would allow more clearance.

    However, with the c-beam z axis mounted like this, no matter how high the gantries are the bottom of the c-beam is your limiting factor. Since you can only get the router so low, and the bits and collet have a fixed length protruding down, you can't go much higher than this and still reach the table with the bit.

    I think the answer is to connect the gantry plate on the z axis to the gantry plate on the x axis. That is, the z axis c-beam is 180 degrees from where it is now. This way the whole z axis c-beam moves up and down. In this way you can get 100-200 mm of z travel. The cross brace would have to go in this instance. I'll do up another mod to see how that works. c-beam router iso.jpg
     
  7. Metalguru

    Metalguru Master
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    Here is a view with the z axis flipped, and the Y gantry uprights extended by 50 mm. I now have 125 mm of z travel and should be able to handle objects 125mm (5") high.

    Just have to put some bolts and spacers between the x- and z- gantry plates. I could flip the bolts holding the wheels around so that the heads are in between the plates, then a 6mm spacer should be plenty between the gantry plates. 4-8 bolts is all that holds the z gantry on, easily accessible.

    Router mount is approximately 35mm from the table at the bottom.

    The nice thing about this is that you just slide the x-z gantry and the brace down and it should make the whole thing much stiffer for doing aluminum plates.

    Oops, I just noticed I got the brace a bit too high. Its rubbing on the x gantry wheels. Not a big deal to move it down a few mm.


    c-beam router gantry.jpg
     
  8. Steve Fox

    Steve Fox Veteran
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    Look at the pictures in this thread:
    Cebu | OpenBuilds
    I thought the way you did until he posted the pictures. He shows that the clearance under the X axis beam is the height limiting factor, not the C-Beam.
    I have to admit, I was amazed.
    I have one to put on my Ox as soon as I get back to North Carolina.
     
  9. Metalguru

    Metalguru Master
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    This does not give you any more clearance on the z axis. He says that he mounted the c-beam with its bottom even with the bottom of the x gantry plate, so they are the same height. The maximum his ox can do is about 2 1/2" z height on the work piece. Since the c beam is fixed, if you try to have a work piece higher than 2 1/2". the bottom of the c beam or the bottom of the x gantry plate will hit it when the y axis moves more than the distance from the collet to the c beam in the y- direction. You could do very small pieces that were a bit higher, but only 2" wide or so.

    Granted he can raise the router higher using the 250mm c-beam, so as he says the tip of the bit can cut from just below the bottom of the end of the c-beam all the way till his collet touches the table. Just means he can use long or short bits without worrying about not having enough z axis travel.

    My design can be adjusted the same way, you can lower the x axis beam way down, which should give a really stiff router mount, or you can slide it up to get 5" or more of work piece height. Not sure what I would be routing that's 5" high but its nice to know you can get there from here.

    Let me know how your machine turns out.
     
  10. Metalguru

    Metalguru Master
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    Another iteration....

    Flipped the y axis c-beams so that the lead screws are on the outside. This should prevent junk buildup in the c section and leadscrew. It also gives me a flat surface to put the scratch board against to help keep everything square.

    Designed a plate to mount the x-z gantry to the uprights, this seems to work good although in combination with the flipped y axis c-beams it does reduce my x axis travel by 50 mm or so.

    I WISH YOU COULD GET 750MM C-BEAM LINEAR ACTUATORS FROM THE STORE, HINT HINT!!! This thing would be about perfect with 750mm x and y axes.

    The x-axis slide and the gantry stiffener can both be moved up and down the y axis uprights. This allows the z gantry assembly to be lowered down close to the table for cutting aluminum and thin materials, which should make the whole assembly much stiffer. It can be raised up for doing thicker pieces or for wood carving.

    The whole router only uses 2 plates, one for all the gantries with both inner and outer wheels, and one for the x-axis c-beam mounts.

    Take a look, give me some feedback guys!

    Metalguru

    c-beam router front.jpg c-beam router front.jpg c-beam router top.jpg c-beam router y gantry detail.jpg c-beam router plates.jpg
     

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  11. Mark Carew

    Mark Carew OpenBuilds Team
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    This is a great looking machine @Metalguru I was messing with the SU a little and thought it may help.
    I lowered the profile and made it a little more stocky of a machine. You could always go longer on the rails to make it bugger, at 1000mm this would make for a nice sign/plate maker. This version also uses all stock parts and should be very strong.
    Hope this helps at the least give some ideas
    Keep up the good work.
    Mark
    SketchUp attached
    c-beam router_rework_pic1.jpg
    c-beam router_rework_pic2.jpg c-beam router_rework_pic3.jpg c-beam router_rework_pic4.jpg
     

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  12. JustinTime

    JustinTime Master
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    Another option is to keep the height but use C-Beams for the uprights. No pic but the .skp will tell. Also, I made a left and right with some minor options.
     

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  13. Mark Carew

    Mark Carew OpenBuilds Team
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    Looks great @JustinTime and now you got me inspired with a few more ideas, gotta love the collaboration here on OpenBuilds! :thumbsup:
    @Metalguru really like the larger C-Beam plates with the double wheel set you have worked up there we may need to add something along these lines to the Part store. Maybe a cross between these and Robert Baileys C-Beam router build I think they would be a big help to have the option for inside out side or both sets of wheels.
    Here is another version with the added mods and stock plates. On this design you could also raise the bed up using taller V-Slot . The Z axis could be turned around as well to gain more height id desired.
    Hope this helps
    c-beam router_rework_1.jpg
     
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  14. Metalguru

    Metalguru Master
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    Hey Mark, Justin, thanks for the feedback. All great ideas.

    Mark, the "lowrider version" would be good for plates and signs. My design allows one to adjust the x-z gantry to whatever height is needed for the job at hand. I originally was going to go with the stock universal plates as you've done, Mark, but wanted something a bit beefier. Using the 6mm material should add a great deal of strength and minimize any flexing. The 20x80 uprights should also be a lot stiffer than just a 3mm or 6mm plate. I like the corner brackets holding the x-axis on, with the y axis reversed there is lots of room for those without limiting x travel.

    My original design had the y gantry plates on the inside, but I thought that that would just make a huge trap for dust and debris under the table. I like the arrangement with the gantry plates on the outside, as I said it makes the bottom sealed better for easier cleanup. I also thought of using a piece of pipe across the front of the table with small holes drilled connected to an air compressor. This would direct air across the table front to back. I am a woodworker, and I have a 4" dust collection system for which I have a huge 18" wide scoop pickup. If this was placed at the back of the table, almost all the debris generated would get blown to the back of the table and sucked into the scoop.

    Justin, I like the c-beam uprights, I also thought of this, but that will lose another 50 or 60 mm of x axis travel. I think they might be a bit overkill. I like most of your other ideas as well.

    Mark, I have attached the design for the gantry plate here as a SKP file. Check it over carefully, I am a beginning sketchup user and there might be some boo-boo's.
     
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  15. Metalguru

    Metalguru Master
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    oops forgot the attachment
     

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  16. JustinTime

    JustinTime Master
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    Not really. Leave the x axis beam as long as you have it in your original design and mount it just as you have in your original design. It doesn't have to go all the way from one upright to the other.
     

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  17. Ronald van Arkel

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    The V-Slot gantry plates with a V-Slot against it is sturdy, real sturdy. The problem is the washers, they make the construction weak. To solve this you just buy another pair of plates, drill large holes (1/2" / 12mm) where the the screws of the wheels go and place that plate between the V-slot gantry plate you have now and the V-Slot that holds the gantry. Use 3mm spacers and a 1mm shim (if needed) to compensate for the 15mm screws you will use to hold everything together.

    On the other hand, and what I do with my unpublished designs, is to tap M5 holes into a 6mm plate for the wheels, using lock-tide (blue) on the screw that hold the wheel. It will be a clean look!

    Like Metalguru said, better to use small plates and V-Slot attached to it. Mark also did it with his Routy and it's sturdier than a 6mm plate alone ;).

    -Ronald
     
  18. Metalguru

    Metalguru Master
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    Hey PuntoMX. Not sure exactly what you mean about the washers? And the second plate, any chance you could do a quick sketch to illustrate?

    I like the idea of using tapped holes on the gantry plates for the wheels. As you say, it would make a clean installation. However, you could only do this for the fixed (without the offset bushing) wheels. With the offset bushing, the bolt hole moves around with the bushing, and does not end up in the center of the wheel. However, you could put the adjustable wheels on the bottom where you can't see them.
     
  19. Ronald van Arkel

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    I'll make a quick drawing, no problem. Indeed, the tapped holes only work for the normal spacers and not with the eccentric ones. By the way, the gantry plate you use in SketchUp have out of spec measurements, with other words, use the one I'm going to upload in a bit ;).

    Give me some minutes and I'll upload an image and a SketchUp file... ...

    upload_2016-1-25_18-12-31.png
     

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    #19 Ronald van Arkel, Jan 25, 2016
    Last edited: Jan 25, 2016
  20. Metalguru

    Metalguru Master
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    Yeah, I'm kind of a beginner with SketchUp, so I'm not surprised. If you can let me know what is out of spec, I'll try to fix it.

    Thanks.
     
  21. Ronald van Arkel

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    It's not you ;). Those plates you took from the C-Beam machine drawing and they are not that exact. We are working on a whole new set of SketchUp drawings from every part in our stores; more precise, more detail, less errors (I hope, doing my best). Those parts will have the same size as the ones for SolidWorks.

    Any way, drawing en file uploaded, forgot to push the "update" button so it took some time :banghead: :rolleyes:. The aluminium colored holes are drilled out or added. The extra holes added are for attaching the V-Slot to the plates else it will be hard to adjust the wheels and Acme block. use 10mm screws and the T-nut backwards, so with the flange pointing out of the V-Slot... I hope that makes sense :D. To como to think of it, you might only be able to use the outer holes or you need to use 9mm spacers for the wheels (3mm spacer on top of the eccentric too)...

    Edit: My bad, no need for those extra holes, those wheels can be adjusted any way as the 80mm V-Slot won't be on top of the screws that go into the eccentric spacers.


    -Ronald
     
    #21 Ronald van Arkel, Jan 25, 2016
    Last edited: Jan 25, 2016
  22. Metalguru

    Metalguru Master
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    Ronald:

    Ahhhh, I get it now. Use the extra plate with clearance holes for the wheel and acme block screw heads to eliminate the washers. Cool, that looks good.

    The wheels and Acme block can be adjusted before you slide on the 20x80 V-slot anyway. You'll have to be careful adjusting the wheels, if you get them too tight you might bow the plate that the wheels are mounted on slightly. Then when you add the v-slot and tighten it up, it will cause the plate to straighten out and may put too much force on the wheels and bend the bolts. That's why it would pay to just leave the bottom wheel bolts uncovered as you say, and adjust the wheels after it was all assembled and tightened up.

    I did look at using the universal plate initially, but I was worried it would bow out at the top and bottom if the wheels were too tight. This is why I decided to use a 6mm plate, it would be much less subject to bowing when the wheels were adjusted. What do you think of the gantry plate I designed with the inside/outside wheels?
     
  23. Ronald van Arkel

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    I'll look into them tomorrow, but some extra wheels added to it would not be a bad idea. I think I can make a design for that, using 4 wheels above and under without reducing the travel distance too much... but they look good as you have them now to start with :). Mark might post something too about his future design...
     
  24. Metalguru

    Metalguru Master
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    Hey Guys:

    So, I've done a few more mods on the c-beam unit, and I think I'm about where I want to be.

    I added another pair of outside wheels to the gantry plates. This now has 6 outside wheels and 4 inside wheels. I made recesses for all of the bolt heads so the plates can be joined together back to back without spacers. The plates are 6mm thick and quite a bit wider than the Universal Plates, with a wider "wheelbase", so should be bulletproof. The 20x80 uprights should also make the gantry a lot stiffer.

    Also added a couple of threaded holes to allow the plates to be fastened together for the X-Z axis without tee nuts. This allows the z axis to be easily removed with just 8 easily accessible screws if needed. Same gantry plates are used for all 3 axes.

    The X-axis c-beam can be high mounted as shown to get maximum clearance for doing thick pieces. It can be swapped with the 40x20 cross brace to bring the axis lower to make the z-axis mounting stiffer for cutting aluminum and thin plates.

    Added a 20x80 extrusion connecting the two gantries underneath the table. This should stiffen things up nicely.

    With the Y gantries on the outside, this keeps junk out of the y-axis leadscrews, and allows the spoiler board to fit snugly between the two c-beams, helping to keep the table square.

    Did a quick sketch of different sizes for this machine. Easily converted to use 500mm, 750mm, or 1000mm for the x and y axes to make 3 different sized machines with all parts exactly the same except for the c-beam axes and the length of the base extrusions. Or you could mix and match, say 1000mm y axes and a 500mm X axis.

    Now I just have to do the g-code to make the plates on my C-Beam Machine, and I'm set to go. The 750mm axis version is shown.


    c-beam 750 side.png c-beam router front.jpg c-beam 750 gantries.png c-beam 750 gantry detail.png c-beam 750 iso.png
     
  25. Ronald van Arkel

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    Hello Metalguru,

    Drop the inner wheels, they won't do much. And if you want the inner wheels, make sure the eccentric spacers are on all on the bottom:

    o---o---o
    e---e---e

    o---o---o
    e---e---e

    e=eccentric, o=original spacer, the normal ones.

    Stiffen the bottom a little up, looks like 2x M5 8mm screws are holding each Y-axis C-beam in place.

    If you want, you can use 1x 20mm + 1x 9mm spacers where you have the 40mm ones (might need a 1mm shim on top to get 30mm total length), and use a small 8*5*1mm shim under the screw head as the screw head might be a bit wide for the motor. The screw heads are 9mm in diameter and you can snap the mounting holes of the motor. Reducing the spacers might give better stability and less vibration.

    -Ronald
     
  26. Metalguru

    Metalguru Master
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    Hey Ronald:

    The inner wheels are a holdover from the original design with only 4 outer wheels. I figured I'd leave them in, can't hurt. They come with the C-beam actuator kit anyway...

    Not sure why you feel that the adjusters need to be on the bottom. I don't see where it would make any difference. Especially on the outside wheels, I'd rather have them on top where they are accessible than have to stand on my head to adjust them. I'll defer if you come up with a good reason for your suggestion...

    Yeah, I agree with your assessment on the c-beam y-axis mounting. I have to figure out a better way to mount the feet and the bed stiffeners.

    I assume you mean the 40mm spacers on the motors. That is the way the kit comes from OpenBuilds, and there is no clearance issue with the bolt heads. I was a bit uneasy about using only 2 motor mount screws but I could see no other way to do it. Shortening them to 30mm would be better both from a stiffness and strength point of view, and there should be enough space in the flexible coupling to bury another 10mm of motor shaft. Good idea!

    Thanks Ronald.
     
  27. Rick 2.0

    Rick 2.0 OpenBuilds Team
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    Oh, yes it can. The mini-Vs are a different thickness than the Solid-Vs and thus require a different length of standoff to get them out to the same center line as the larger wheels and these standoff lengths/shim thicknesses are not readily available. If you don't get them lined up however they will bind up your system.
     
  28. Ronald van Arkel

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    Like @Rick 2.0 said, although you can make your plates thinner at some spots to use the stock spacers, but it's not recommended to use the mini wheels and just ad that extra full size wheel to the design.

    Eccentric spacers are not used for load, they are there to adjust the wheels so play is less on the V-Slot/C-beam, this is a rule you must apply when designing. Don't get the kit, build your own BoM always ;).
    The motor mount holes can snap when you use the low profile screws from openBuilds directly on the motors. Sure this is after some time or when you torque the screws to much. Using the 8*5*1mm shims will reduce the risk.

    On all my new designs I use indeed the reduced spacers for the motors, I also use the M8 shim (12*8*1mm) in between the flexible coupling and the plate, using BAT3 grease for less noise/friction. I never use them on the collar of the Acme screw. The flexible coupling will be pushed against the shim and will reduce even more play on the Acme design. We talking in another topic on using needle bearing, the 2mm thick ones, to put between plate and coupling; to tell you the truth it works fine with some grease and shim only ;).

    -Ronald
     
  29. Metalguru

    Metalguru Master
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    Rick, Ronald:

    Not seeing what the issue is here, guys. Using the models done by OpenBuilds, it seems to me that within a tolerance of .2mm or so, the offset on the mini wheels and the standard wheels is exactly the same. Now this is using models you guys made, so if I can't trust those what am I supposed to do? I measured several of the wheel assemblies in my model from the plate to the center of the wheel, and regardless of whether they were full sized wheels or mini wheels, the distance was 12.5mm +/- .2mm. This is close enough for the girls I go out with...

    The only difference is that the mini wheels have 2 x 1mm precision shims instead of 1 on the regular wheels. This makes sense, since the standard wheels are 11mm wide from bearing face to bearing face, while the mini wheels are 9mm wide. This would mean to get the same center, the mini wheels would require one more 1mm shim than the standard wheels. This standoff/shim combination is not really "nonstandard".

    Looking at the plates I built using parts from the OpenBuilds models, there ain't enough difference by eyeball that it would bind.

    As far as the offset adjusters, can't really agree there either. The load bearing strength of the wheel comes from the bolt, not the spacer, and regardless of whether there is a solid spacer or an eccentric spacer, the bolt is the same. The bolt is supported inside the spacer in either setup, the only difference is a few mm of smaller hole in the plate with the solid spacer. This would be offset by the better strength of the offset spacer because it has a longer path where the bolt is supported inside the spacer. I can't see that there would be any significant difference in strength between the two setups, especially with 3mm universal plates. With thicker 6mm plates, there might be a bit of difference, but IMHO not enough to worry about.

    Ronald, I'm also not getting your comments about putting the 8mm shim on the coupling side of the plate. I built my C-Beam machine by putting the lock collars on the 8mm lead screw with one of the end plate's screws loosened off a bit. Once the lock collars were tightened down, I tightened up the screws on the end plate. This puts a preload on the lead screw so that it can't move end to end and so maintains maximum accuracy. The shim is needed between the locking collar and the bearing so that the outside diameter of the locking collar (which turns) does not rub on the outer bearing race (which does not turn).

    Your method of putting the shim on the other side of the plate and using the coupling to put some preload on the lead screw would work, but is much harder to do. The grease doesn't help here either, since the lead screw, shim, bearing and coupling all rotate at the same time, so there is no need for grease since there is no sliding friction... You are essentially using the shim as a spacer to keep the flex coupling from rubbing on the end plate, which is OK, but I don't think leaving out the shim on the locking collar side is a good idea.
     
  30. Ronald van Arkel

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    I'm working on new models for SketchUp, the ones provided now are a bit too rough to be precise. For example, the mini wheels are 4.2+1+.4.2mm wide (bearing+shim+bearing), total of 9.4mm vs. 11mm of the full-size wheel. using a shim of 1mm extra will still be 0.6mm short, using a 6.35mm / 1/4" spacer instead of a 6mm spacer will still be 0.25mm off (close to your 0.2mm). 0.25mm Doesn't look like much but the wheel will not put any load on one side of the wheel and also life of the bearings will be shortened (easy to swap out, I know).

    Eccentric spacers is normally placed at the bottom. This way you have the construction always at the same level with the non eccentric spacers. The eccentric spacer has an offset of 0.79mm, and so, when you put the full load on a wheel (you never will get there but still) you can get a difference of 2x 0.79mm, total of 1.58mm difference, with a totally "lose" eccentric spacer. This is what I wanted to what I said before.

    On the M8 shim for the Acme screw, let me take a look as I remember it didn't rub against the outer part of the bearing. If so I need to adjust some designs, no big deal, and I will thank you for that ;).

    -Ronald

    EDIT:
    I checked, the lock-collar will not touch the outer part of the bearing, I wish I had a good camera that could zoom in well but I don't have it. You just have to trust me on this one. But, to be safe, you can keep the shim where it is.
     
    #30 Ronald van Arkel, Feb 8, 2016
    Last edited: Feb 8, 2016

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