Stiffness of the spindle carriage plate

discussion of design changes / improvements / suggestions
cvoinescu
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Re: Stiffness of the spindle carriage plate

Post by cvoinescu » Sun Mar 06, 2016 1:54 am

Atonwa wrote:Here is the setup on the Routakit with steel rails and steel wheels on the Z. It's an aluminum spacer block with a steel linear rail (Grainger) attached to it with the Openbuilds steel wheels.
No offense, but, for the money, the OpenBuilds steel wheels suck. They still use the same cheap deep-groove bearings (625) as the Delrin V-wheels. I have sampled 625 bearings from the cheapest cheap stuff to quite expensive branded ones, and they all seem to have some axial play. For about the same money, you can buy a steel V-groove bearing, which is a one-piece dual-row angular bearing with a 90 degree V groove. It's much better than the OpenBuilds four-part wheel.
Proud owner of ShapeOko #709, eShapeOko #0, and of store.amberspyglass.co.uk

jkanzaki
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Re: Stiffness of the spindle carriage plate

Post by jkanzaki » Sun Mar 06, 2016 1:59 am

Atonwa wrote:
AnonymousPerson wrote:Interesting. That looks pretty solid.

I'd been wondering how to get and keep a good straight edge on new X/Y rails, if I go for steel box versions instead of buying the Carbide 3D expansion kit.

Something like these Grainger ones seem like they'd do the trick:

https://www.grainger.com/product/PBC-Li ... Rail-2CRW4

What do you reckon? :)
Those are the ones on my machine I believe. Hardened steel and they are built just like OpenRail so you lip it over the edge. It really shouldn't be that difficult to modify the S3 to accept them. Simply make an aluminum spacer block that accepts these and bolts to the existing holes.

Only bummer is $82 a rail so if you could find a couple people interested to split the costs of materials it wouldn't be bad.
I see your point, the aluminum spacer block need to be design fit these steel linear rail at the right thickness. Then I can mount the linear rail on it. I am very intrigue about this idea now.
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jkanzaki
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Re: Stiffness of the spindle carriage plate

Post by jkanzaki » Sun Mar 06, 2016 2:03 am

cvoinescu wrote:
Atonwa wrote:Here is the setup on the Routakit with steel rails and steel wheels on the Z. It's an aluminum spacer block with a steel linear rail (Grainger) attached to it with the Openbuilds steel wheels.
No offense, but, for the money, the OpenBuilds steel wheels suck. They still use the same cheap deep-groove bearings (625) as the Delrin V-wheels. I have sampled 625 bearings from the cheapest cheap stuff to quite expensive branded ones, and they all seem to have some axial play. For about the same money, you can buy a steel V-groove bearing, which is a one-piece dual-row angular bearing with a 90 degree V groove. It's much better than the OpenBuilds four-part wheel.
So you reckon steel V-groove bearing eh. I never thought of the axial play matter much for the openbuild V wheel. Does it really?
What would be the spec for one of these steel V-groove bearing? or you have an example link?

I think what Atonwa sugguest for the steel linear rail is a descent upgrade from the current design on the SO3.
Shapeoko 1 - dissassemble
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Atonwa
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Re: Stiffness of the spindle carriage plate

Post by Atonwa » Sun Mar 06, 2016 2:21 am

You can buy the proper bearings for the rail specified above here...

http://www.pbclinear.com/V-Guide-Roller ... Components

I've used this company at work on $500K+ equipment with no issues.

Update: And if you really want to dig into these linear rails here's a white paper on them with an interesting alternative system supplied by the company.

http://www.pbclinear.com/Download/White ... -V-Rollers
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Atonwa
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Re: Stiffness of the spindle carriage plate

Post by Atonwa » Sun Mar 06, 2016 2:43 am

And as I fall down the rabbit hole this video makes me think of what you could build for all axis. Since the Shapeoko rails are all proprietary now why not go with a version you can purchase from a known company.

This would be a fun custom build with these IVT rails if money was no object :D

http://www.pbclinear.com/IVTAAG?tab=ProductOverview

**Click on the video tab and watch their overview**
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cvoinescu
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Re: Stiffness of the spindle carriage plate

Post by cvoinescu » Mon Mar 07, 2016 3:29 am

jkanzaki wrote:I never thought of the axial play matter much for the openbuild V wheel. Does it really?
What would be the spec for one of these steel V-groove bearing? or you have an example link?
Any axial play in the Z V-wheels you'll see at the tip of the spindle, amplified by the lever effect. It's true for the Delrin wheels, and switching to the OpenBuilds steel wheels does not improve this at all. (They are much better in other respects, but not this.)

For more information on the V-groove bearings, you can search for RM0ZZ and RM1ZZ, which are the smallest common sizes. They have inch-based dimensions, and RM0 has an ID of just under 5 mm. Both Inventables and myself sell a custom-made version of RM0ZZ with an ID of 5 mm. I don't have specs for it, though.
Proud owner of ShapeOko #709, eShapeOko #0, and of store.amberspyglass.co.uk

jkanzaki
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Re: Stiffness of the spindle carriage plate

Post by jkanzaki » Mon Mar 07, 2016 7:44 am

cvoinescu wrote:
jkanzaki wrote:I never thought of the axial play matter much for the openbuild V wheel. Does it really?
What would be the spec for one of these steel V-groove bearing? or you have an example link?
Any axial play in the Z V-wheels you'll see at the tip of the spindle, amplified by the lever effect. It's true for the Delrin wheels, and switching to the OpenBuilds steel wheels does not improve this at all. (They are much better in other respects, but not this.)

For more information on the V-groove bearings, you can search for RM0ZZ and RM1ZZ, which are the smallest common sizes. They have inch-based dimensions, and RM0 has an ID of just under 5 mm. Both Inventables and myself sell a custom-made version of RM0ZZ with an ID of 5 mm. I don't have specs for it, though.


I am just thinking if I am going to disassemble my SO3 then I'll mind as well do all the mod at once rather than take it apart later.

I will definetly add braces and alumium support to the z axis plate as part of my mod, but I just want to know if I get the PBC steel linear rail, inventable rm1zz steel wheel, add additional two more v wheel on the z axis plate and custom cut a alumium spacer for the rail.
>>>>How much more improvement will I get ? <<<<
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northbear
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Re: Stiffness of the spindle carriage plate

Post by northbear » Mon Mar 07, 2016 8:59 pm

Atonwa wrote:You can buy the proper bearings for the rail specified above here...

http://www.pbclinear.com/V-Guide-Roller ... Components

I've used this company at work on $500K+ equipment with no issues.
Another company is Bishop-Wisecarver - http://www.bwc.com/products/components- ... alvee.html

Probably common knowledge but just in case someone doesn't know, Makerslide (http://www.makerslide.com/) was designed as a cheaper alternative to these types of rails and wheel. Makerslide was used on the SO1 and SO2. The SO3 uses a larger extrusion, but the same theory.

I always chuckle a bit when the discussion about how to make ShapeOko better comes back around to the same type of bearing that these extrusions were getting away from in the first place because of their expense! Valid point as they are a better bearing system, but still feels like talking / designing in circles!

Personally, I think the Shapeoko is suffering a bit of mission creep as it is. While I believe the SO3 is a *much* more capable system than the original Kickstarter, it is also $1000 (ok $999) machine rather than the $300 goal it started out as. Is the SO3 a great value for the price? I believe it is, but what got me interested in building a CNC in the first place was the low cost of entry and the open source nature of the ShapeOko and I think the low cost of entry has been lost.

Sorry, got a bit off topic there!
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WillAdams
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Re: Stiffness of the spindle carriage plate

Post by WillAdams » Mon Mar 07, 2016 9:19 pm

Yeah, the price point is the crux of the matter.

The question becomes, how good of a CNC can one have at what low price point(s).

I'd really like to see a machine at the original $300 (slightly higher adjusted for inflation?) --- esp. if matched up w/ the original goal of fitting w/in a USPS flat-rate box.
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cvoinescu
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Re: Stiffness of the spindle carriage plate

Post by cvoinescu » Mon Mar 07, 2016 11:24 pm

northbear wrote:While I believe the SO3 is a *much* more capable system than the original Kickstarter, it is also $1000 (ok $999) machine rather than the $300 goal it started out as.
A valid point, but I have to say that the comparison is not entirely fair. The $300 in the Kickstarter was cost in materials for a hobbyist buying parts at retail, using parts they already have at hand, maybe pulling some favors to get plates laser-cut at "mates rates", and generally not afraid of spending time to save money. It's true that doing large batches saves money, because unit prices go down; but it's also true that doing it as a business adds a lot of costs. A business need to keep doing R&D so it doesn't become irrelevant, and earn some profit for the owners -- and, even more importantly, a business can't trade time for money the same as a hobbyist, because its employees' time is not free.

So the retail prices of the SO1, SO2 and SO3, on one hand, and the stated $300 project goal, on the other hand, are not the same kind of cost and can't be compared directly -- at least not fairly.
Proud owner of ShapeOko #709, eShapeOko #0, and of store.amberspyglass.co.uk

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