1 Topic by pcm81

  • pcm81
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Topic: Vgroove vs shaft

I have a question. What are the advantages/disadvantages of using vgroove support system vs shaft system? I'd venture a guess that vgroove can be wider and hence can support bigger load over a longer distance. Are there any other advantages?

I am thinking for a 2ftx2ft 3d printer application for the Y axis.

Thanks ahead

2 Reply by Tomek

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Re: Vgroove vs shaft

Pro V-groove (I like openbeam m
(1) cost. Alu cheaper than good shafting, moreover, doesnt have as high bearing costs.

(2) weight

(3) moment of cross section inertia and bending forces. The aluminum can be stiffer because its not a simple rod

Pro Shafting:
(1) more established history
(2) Fewer wear and tear concerns vs. aluminum
(3) In general some people love steel

3 Reply by adrian (edited by adrian 2014-02-24 13:37:43)

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Re: Vgroove vs shaft

You can also incorporate the rail right into the support structure without neededing to support the rod; such as:

http://www.buildlog.net/forum/download/file.php?id=5303&mode=view

(Image lifted from a random project found on front page of http://www.buildlog.net/ .... home of Makerslide...)

You'll see theres quite a reasonable amount of travel in that setup and its for a laser - so its rock solid.

Extruded alu will be a lot less prone to flex at the midpoints than rods - unless you go to really really big rods. Even 16mm rods will flex over a reasonable distance (meaning <80cm's)... and 16mm rods weigh a *lot*...

Its also loads quieter (virtually silent).

4 Reply by pcm81

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Re: Vgroove vs shaft

Thanks guys. Great stuff.

5 Reply by danny

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Re: Vgroove vs shaft

Pro V-groove (I like openbeam m
(1) cost. Alu cheaper than good shafting, moreover, doesnt have as high bearing costs.

I'd tend to disagree on this.

shafts seem to have brass bushings mostly, but occasionally linear bearings.
while V grove systems are still going to need at least 1 bearing for a like for like comparisson, and possibly wheels attached to the bearing.

overall it's probably 6 of one and half a dozen of the other.

v grove and box sections etc probably are significantly cheaper over larger spans though than shafts.


a 2ft x 3ft printer is almost certainly going to have some flex in at least 1 axis, if you have 0.5mm flex over the x axis and 0.5 flex at the centre of the y that's 1mm overall... (that's 3 layers at 0.3, or ten layers at 0.1mm resolutions)

Another benefit of box and vgrove type systems is that they tend not to be enclosed like shafts are so you should be able to arrange extra support in at least 1 axis if not both to minimise the flex possible...


are you planning of logging the build anywhere? I'd be interested to follow this as I'm planning a large span printer myself... it'd be good to see if you run into any dead ends so that I know not to go down that path! (and visa versa of course.)