best rigidity mods for SO2?

discussion of design changes / improvements / suggestions
WillAdams
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Re: best rigidity mods for SO2?

Post by WillAdams » Wed Aug 20, 2014 10:08 am

That's something we still haven't reached a consensus on.

My inclination is to try the Makerslide joining clips once I get a 3D printer calibrated: http://www.shapeoko.com/forum/viewtopic.php?f=12&t=1810

http://www.thingiverse.com/thing:74301

The alternative is to drill holes in at least one of the pieces --- we've discussed it quite a bit, but don't have as many links here: http://www.shapeoko.com/wiki/index.php/ ... ide_X-Axis as there should be.
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cvoinescu
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Re: best rigidity mods for SO2?

Post by cvoinescu » Wed Aug 20, 2014 11:36 am

ijv wrote:Whats the best way of bolting the x-axis together? Also are there any bolting locations on the x-axis that gets you the most rigidity for the hole? :)
There is no "best" way -- or, there is, but best for what?

I find my method is a good compromise: it requires only simple dirlling with no particular accuracy, no tapping, and no gouging the sides of the T-slot to clear larger bolt heads; and it's not permanent like glue (or welding -- wouldn't that be overkill?), so later adjustment is still possible. It's not the most rigid way, but M3 screws are surprisingly tough nonetheless.
Proud owner of ShapeOko #709, eShapeOko #0, and of store.amberspyglass.co.uk

Woodworker
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Re: best rigidity mods for SO2?

Post by Woodworker » Wed Aug 20, 2014 12:00 pm

I can't see where a piece of plastic joining both pieces at the end is going to significantly increase the resistance to twist. Perhapse if they were metal and were the same length as the rail? What are the setup costs to have something like this made from aluminum?
BRuce - SO2 #4798 - IC's Z axis upgrade, customized Z rail and Z motor mount, spindle Dewalt 611

ronniemcd
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Re: best rigidity mods for SO2?

Post by ronniemcd » Wed Aug 20, 2014 12:06 pm

Woodworker wrote:I can't see where a piece of plastic joining both pieces at the end is going to significantly increase the resistance to twist. Perhapse if they were metal and were the same length as the rail? What are the setup costs to have something like this made from aluminum?
That's the beauty of them, you stack them in as many as you like to increase the hold they have.

Woodworker
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Re: best rigidity mods for SO2?

Post by Woodworker » Wed Aug 20, 2014 12:20 pm

The instructions say to "hammer them in the ends", so I have a 900mm X axis and would like it joined in the middle. So I get a 500mm rod and drive them all the way to the center? I'm not try to be a pain I'm just trying to gather info for my next upgrade. This seems like a good idea for shorter lengths of rails.
BRuce - SO2 #4798 - IC's Z axis upgrade, customized Z rail and Z motor mount, spindle Dewalt 611

Halfdead
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Re: best rigidity mods for SO2?

Post by Halfdead » Tue Dec 23, 2014 2:03 am

I went ahead and bolted my x axis together, now I'm wondering where I can find the right length spacers, it's 52.7 mm between the two plates. Times like this I wish I had a metal lathe...

chomdh
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Re: best rigidity mods for SO2?

Post by chomdh » Tue Dec 23, 2014 3:23 am

I'm also curious about how to reduce the amount of "twist" the z axis mounting plate has. My z axis v-wheels are pretty tight against the rails, but I notice a fair amount of motion when I push on it with my thumbs. I'm thinking this could be a source of some inconsistencies in my parts and carvings.
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Soon to have inventables spindle mount and 1M X axis.

chomdh
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Re: best rigidity mods for SO2?

Post by chomdh » Sun Dec 28, 2014 2:25 pm

When I further examine the v-wheel assemblies, the bearings seem to have a larger than expected amount of internal clearance (space between the balls and races). When they manufacture the balls, they are sorted by size before they are assembled into the races so that you can buy different internal tolerance classes. Does anyone know what internal clearance class the v-wheel bearings have?

I've ordered a 5th and 6th v wheel kit for my z axis plate which haven't yet arrived but if going to a reduced internal clearance bearing is an option I may try that as well. Since the z axis v wheel bearings move so slowly I don't believe reducing the internal clearance will have any negative side effects.
Shapeoko2 #3702:
DW611, arduino uno, gshield v5, NEMA23's on X & dual Y, NEMA17 on Z with ACME rod, 9mm belts, Mean Well NES-350-24V power supply, re-inforced gantry rails.
Soon to have inventables spindle mount and 1M X axis.

WillAdams
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Re: best rigidity mods for SO2?

Post by WillAdams » Sun Dec 28, 2014 3:37 pm

Unfortunately, we don't know what the ABEC rating for the bearings which Inventables sources is. (Article about skateboard bearings here: http://skateboard.about.com/od/gear/f/ABEC_Bearings.htm )

I'd really like to get a bit written up for this for the wiki:

- ABEC rating
- minimum ABEC rating for usage --- what is the point of diminishing returns?
- does a particular axis benefit from a better rating? (My thinking is the Z- wants the best, then X-, and Y- last or the same as X-)
- how does the usage of eccentric nuts influence this? I'm thinking that if one were to tighten an eccentric nut up so that a bearing was trapped so that the smallest ball bearing in the races was at that point it would be locked there and induce additional wear

Interesting link discussing this sort of thing in a CNC context: http://solsylva.com/cnc/bearing_trials.shtml

And of course, there's a thread on CNC Zone: http://www.cnczone.com/forums/diy-cnc-r ... -abec.html
Shapeoko 3XL #0006 w/ Carbide Compact Router w/0.125″ and ¼″ Carbide 3D precision collets
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galyion
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Re: best rigidity mods for SO2?

Post by galyion » Wed Dec 31, 2014 3:39 pm

there should be almost no measurable play in the bearing themselves. maybe .0005" tops.

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