Dual Drive Setup (with driveshaft)

discussion of design changes / improvements / suggestions

What would your dual drive preference be?

Drive Shaft
30
41%
Dual Motor
41
56%
Something Else
2
3%
Nothing
0
No votes
 
Total votes: 73

WillAdams
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Re: Dual Drive Setup (with driveshaft)

Post by WillAdams » Sat Feb 09, 2013 6:16 pm

WillAdams wrote:if I'm stuck w/ the 3/16" rod, I've been trying to work out a good way to hold the pieces in alignment --- best I've thought of is getting some 7/32" rod and turning it down as two steps (first 3/16", the other 5mm), but I'm concerned about maintaining the concentricity.
May have a solution on that. The 1/4" shaft collars I just sourced have an o.d. of 1/2", as does the metal portion of the 5mm pulley, so if I get some metal tubing w/ 1/2" i.d., I should be able to use it --- if I drill at 90 degrees to the set screw, I should be able to hold everything together thus.

But that didn't work out 'cause the bronze bearing which was the only reasonably priced metal tube w/ 1/2" i.d. is a sloppy fit over them... perhaps a 1/2"--3/16" shaft coupler?
Shapeoko 3XL #0006 w/ Carbide Compact Router w/0.125″ and ¼″ Carbide 3D precision collets

WillAdams
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Re: Dual Drive Setup (with driveshaft)

Post by WillAdams » Tue Feb 12, 2013 3:16 pm

Grrr. Waiting on couplers ordered from China via eBay to arrive.

In the meanwhile, am regretting fscoupling not having a ``normal'' 6.35mm to 5mm coupler. They do have this:

http://www.fscoupling.com/5mm-to-635mm- ... -p-57.html

but ``flexible'' in the description makes me leary of it --- should I not be? (AND the answer is, yes, that's a a serious concern and makes the use of a flexible coupler a non-starter due to backlash as discussed previously on the Google Groups group)

Failing that, if I turned around the 5mm pulley on my drive shaft, so that the metal shaft collar portion was facing out, perhaps I could then use:

http://www.fscoupling.com/635mm-to-127m ... p-139.html

which would have the benefit of making everything a bit shorter.

Arguably, all of this just indicates the preferability of just using a NEMA 23 for a drive-shaft machine so as to take advantage of just using a 1/4"--1/4" coupler.
Last edited by WillAdams on Fri Feb 15, 2013 1:05 pm, edited 1 time in total.
Shapeoko 3XL #0006 w/ Carbide Compact Router w/0.125″ and ¼″ Carbide 3D precision collets

WillAdams
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Re: Dual Drive Setup (with driveshaft)

Post by WillAdams » Fri Feb 15, 2013 1:04 pm

Okay, couplers arrived early, and of course, I finally figured out how to find them on Amazon's small parts supplier list:

http://www.amazon.com/Ruland-PSMR16-5-5 ... ISHQ&psc=1

EDIT: had the wrong part --- the right one is a _lot_ pricier --- guess we're back to ordering from China off eBay...

Hopefully this evening I'll be able to document the 1/4" drive shaft option, along w/ Tom Smith's which is already on the wiki and the couple of others which are on the forum we should have everything nailed down pretty well. The one issue I'm seeing is the size of the hole on the plates being different for different batches --- need to look up which batch that changed on, and we also need to get the engineering drawings on github up-dated to reflect the change. I figure we'll have a table, working from small / inexpensive to larger / more expensive and complex from top-left to bottom-right w/ all the details and purchase links and price totals in the right column.

Once we get this done, I'd really like to see it as a project on Inventables like the dual drive option. If that's not happening, I guess I could look into stocking the parts as kits. Ordering the couplers in bulk should keep the price down, and everything but the drive shaft would fit in a flat rate box. If you're interested, send me a PM.

William
Shapeoko 3XL #0006 w/ Carbide Compact Router w/0.125″ and ¼″ Carbide 3D precision collets

WillAdams
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Re: Dual Drive Setup (with driveshaft)

Post by WillAdams » Sat Feb 16, 2013 4:20 am

And some more snags:

- reversed my bolt order (long M5s, short M3s), so ran around this evening getting M5 bolts --- still need to source 45 or 50mm M3s --- suggestions on places to look?
- looks like the Z-axis threaded rod is in the way, so will have to do the longer Y-axis so I can double up the Makerslide on the X-axis which should move that out of the way
- so I also need 70mm M5s and probably some more spacers and washers --- will have to see if I can manage all aluminum spacers

Can anyone think of anything else I missed?
Shapeoko 3XL #0006 w/ Carbide Compact Router w/0.125″ and ¼″ Carbide 3D precision collets

WillAdams
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Re: Dual Drive Setup (with driveshaft)

Post by WillAdams » Sat Feb 16, 2013 11:10 pm

I forgot to mike the 1/4" music wire --- it's too large for the coupler or pulley to fit.

Managed to get 50mm M3 pan head machine screws and other odds and ends (at the local True Value), and was able to drill the holes for dual Makerslide so once I sand the wire down or source a properly dimensioned rod, I should be all set.
Shapeoko 3XL #0006 w/ Carbide Compact Router w/0.125″ and ¼″ Carbide 3D precision collets

WillAdams
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Re: Dual Drive Setup (with driveshaft)

Post by WillAdams » Sun Feb 17, 2013 1:45 pm

Now that we have an official dual motor Y-axis drive kit, price comparisons are a bit easier:

$58.42 for the https://www.inventables.com/projects/sh ... -drive-kit

To get only the items the two upgrades have in common we subract:

$16.94 Stepper Motor - NEMA 17
$3.00 3 ft. Stepper Motor Cable
$2.50 Terminal Block
=====
$22.44
(but should also account for a 4th stepper driver, $9.95--$11.95)

We need to set off the motor so as to not lose working area:

$2.00 25285-14 50mm 0.5mm 10 M3
$6.00 25312-08 0.7500 in 10
$2.00 25287-03 Zinc Plated 3.1mm 7mm 10 .45mm - .55mm

Ideally the screws would be 45mm the longer screws will need washers to make up the difference (I used 3 M3 and 5 M5) if one isn't willing to cut them. Nylon spacers would be cheaper, ~$1.60 --- I was able to pick up 4 steel 1.5" 7/32" rolling pins for $1.60. However, this arguably should be done for the motor as well, so as to not lose working area, so we'll call it a wash.

Assuming a 1/4" drive shaft we need to switch out the 5mm pulley for a 1/4"

$6.25 25204-03 .25"

+0.75

Inventables has 1/4" aluminum rods in the following alloys --- not sure which would be best for a drive shaft. For an 18" length (a stock Shapeoko needs ~17") prices run from

$4.21 24792-30 1/4" 18" (2011)
$10.71 24793-02 1/4" 18" (2024)
$1.21 24794-09 1/4" 18" (6061)
$2.26 24795-02 1/4" 18" (7075)

and Home Depot has ``Everbilt 1/4 in. x 36 in. Aluminum Round Rod'' for $4.21 and True Value hardware stores stock K&S Engineering 1/4x36 ALU RND Rod for $3.49

Anyone know the tradeoffs for these alloys? (I went ahead and asked the Inventables folks about this)

$4.21

We need a shaft coupler --- I was able to find them on eBay quite inexpensively, but I think the perfect solution is to use an over-size one which would connect the drive shaft to the pulley, allowing the belt to move to the outside:

$12.00 6.35mm to 12.7mm Linear Motion Control Couplings 1/4 x 1/2 In Encoder Clamp Shaft Coupler Diameter 25mm Length 30mm at http://www.fscoupling.com/635mm-to-127m ... p-139.html (Amazon has the same for $13.99)

This essentially makes the dual-purpose pulley--coupling I wished for above.

And we need a flanged bearing:

$6.72 Kilian F-160 1/4" Bore, 13/16" Minor Diameter, 29/32" Flange Diameter, 1/4" Wide Flanged Bearing available at Amazon http://www.amazon.com/Kilian-Diameter-F ... B003XU6QW0

The motor hole will need to be adjusted in size --- a 7/8" tapered reamer should work for that, (though I worry about making such a large hole), or you can make a bearing plate out of HDPE and mount it w/ M3 screws. Or, one could find the proper sized bearing (found by searching on .25 i.d. instead... $6.49, but not a small parts item, http://www.amazon.com/2500-Flange-Flang ... B002HAXAFI )

$23.68 (or less) versus $32.39 or ($22.44 if _not_ using a 4th driver)

My build came in at quite a bit less (if I only counted actually used parts) --- the roll pins are a nice savings, the aluminum rod was cheap and I got a 5mm--6.35mm coupler off eBay for $3.97.

The 5mm variant should in theory be cheaper, but it's not, given the parts I can find. For reference:

$10.77 Tool Steel Round Rod, Ground Finish, Grade O1, Annealed, Meets ASTM A681 Specifications, 5millimeters Diameter, 36" Length, Precision Tolerance http://www.amazon.com/Annealed-Specific ... B0050RMUT2
$6.79 F624ZZ Miniature Flanged Ball Bearing 4x13x5 mm Shielded by ESI Bearings http://www.amazon.com/F624ZZ-Miniature- ... B009H6X1TK
$7.49 http://www.pololu.com/catalog/product/1203 plus 8 #4-40 Machine Screws, 1/2" Length, Phillips http://www.pololu.com/catalog/product/1962 (25-pack). $23.11 Ruland PSMR16-5-5-A Set Screw Beam Coupling, Polished Aluminum, Metric, 5mm Bore A Diameter, 5mm Bore B Diameter, 15.9mm OD, 20.3mm Length, 1.36 Nm Nominal Torque http://www.amazon.com/Ruland-PSMR16-5-5 ... B0060M1XLM (from China on eBay, purchased from Member id bluestone002, this was $2.99 + $1.56 s/h)

The drive shaft is in place, see signature, (though the pulley was a nerve-wrackingly tight fit, despite test fitting in the store), so just need to install the belts, square the machine, bolt it down and tighten things up.

To do:

- source a 1/4"--1/2" coupler and move the motor belt to the outside as theorised above
- drill new holes for the idler wheels so the belts can be flipped over and work out suitable mounts / end plates
- organise the above and add it to the wiki, merging w/ Tom Smith's --- I was thinking a table w/ columns for different shaft sizes....
- anything else I forgot....

William
Shapeoko 3XL #0006 w/ Carbide Compact Router w/0.125″ and ¼″ Carbide 3D precision collets

g2ktcf
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Joined: Wed Feb 13, 2013 8:35 pm

Re: Dual Drive Setup (with driveshaft)

Post by g2ktcf » Tue Feb 19, 2013 9:10 pm

William,

Just wanted to share this with you.

http://www.sdp-si.com/eStore/CoverPg/Dr ... onents.htm

I have found some nice deals with these guys. I think the drive shaft is preferable over the dual motor system and I cannot wait to get mine unit working so I can start upgrading! (finished bolting everything together last night!)

Cheers,
Chris

cvoinescu
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Re: Dual Drive Setup (with driveshaft)

Post by cvoinescu » Tue Feb 19, 2013 10:04 pm

g2ktcf wrote:http://www.sdp-si.com/eStore/CoverPg/Dr ... onents.htm
The SDP/SI catalog is huge. Is there any item in particular that you were thinking about?
Proud owner of ShapeOko #709, eShapeOko #0, and of store.amberspyglass.co.uk

WillAdams
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Re: Dual Drive Setup (with driveshaft)

Post by WillAdams » Tue Feb 19, 2013 10:20 pm

At one point in time, I found some things on that site, but never enough to justify an order --- we really need a vendor / list page.

Chris, as I noted, mine is in-place, just need to get ``one more thing'' --- let me know if you have any questions or suggestions for the drive shaft page on the wiki:

http://www.shapeoko.com/wiki/index.php/Drive_Shaft

I'll try to combine the above w/ that page so we'll have it all in one place.

William
Shapeoko 3XL #0006 w/ Carbide Compact Router w/0.125″ and ¼″ Carbide 3D precision collets

WillAdams
Posts: 8608
Joined: Mon Apr 09, 2012 6:11 pm
Location: Pennsylvania --- south of the Turnpike, East of US-15
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Re: Dual Drive Setup (with driveshaft)

Post by WillAdams » Sat May 11, 2013 3:04 am

Combined.

I think we've got all the implemented versions pretty well-documented, plus 2 theoretical versions which should be fairly straight-forward to implement.

Interesting things:

- rotated the motor so I could use the NEMA 23 holes for the idlers --- looks pretty cool:
wfa-shapeoko-rotated-motor.jpg
wfa-shapeoko-rotated-motor.jpg (214.71 KiB) Viewed 2662 times
- may need to add a bearing at the motor end --- was thinking a 1/2" oil-impregnated bronze thrust bearing would be a good choice --- thoughts on how to secure it?

- the 60mm M3 screws are holding better than I expected them to at that length, but I still wish there was a way to mount the motor closer w/ belts outside

Just need to file out some slots and drill two holes, then I can finish putting it together (tomorrow).

William
Shapeoko 3XL #0006 w/ Carbide Compact Router w/0.125″ and ¼″ Carbide 3D precision collets

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