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

minorthreat
Posts: 43
Joined: Tue Apr 24, 2012 4:34 pm
Location: Boston, Ma

Re: Dual Drive Setup (with driveshaft)

Post by minorthreat » Thu Jan 03, 2013 5:16 pm

Here is my drive shaft. I have the larger spark fun steppers (nema23) so i went with a 1/4" shaft.

The drive shaft is riding on these bearing: http://www.mcmaster.com/nav/enter.asp?partnum=57155K337
This coupling joins the drive shaft to the stepper shaft:http://www.mcmaster.com/nav/enter.asp?partnum=2424K11
I had a pack of flanged bearings lying around so I used those for my idler pulleys
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WillAdams
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Re: Dual Drive Setup (with driveshaft)

Post by WillAdams » Mon Jan 21, 2013 5:42 pm

How many of these parts could one get from Inventables? Where can the balance be sourced?

- Dual Drive Shaft --- there are a lot of choices for round stock --- what should one use?
- need a pair of pulleys --- https://www.inventables.com/technologie ... -mxl-pitch (one can be recycled from the Shapoko?)
- motor recycled from Shapeoko
- 21 4 AS 1420 - 1973 - M3 x 10 ISO metric hexagon socket head cap screws ( https://www.inventables.com/technologie ... -cap-screw )

Other necessary things:
- a pair of flanged bearings which match the end plate hole size --- buy from a local hobby shop which specializes in RC models?
- 1 SMS003 Dual Drive Bearing Pocket
- 18 2 pololu_1203 Pololu Universal Aluminum Mounting Hub for 5mm Shaft Pair
- 19 1 57485K65 Metric Set Screw Shaft Collar Steel, 5mm ID, 12.7 mm OD, 6 mm Width
- 22 4 ANSI B 18.2.4.1 M - M3 x 0.5 Hex Nut

The dual drive shaft really appeals to me since I want to reserve the extra stepper controller for a 3D printing head.

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 02, 2013 10:40 pm

Is there such a thing as a pulley w/ 2 shaft collar like ends w/ set screws which could double as a coupler?

If there is, a dual-driveshaft upgrade could be reduced to:

- pulley/coupler
- 5mm metal rod
- flanged bearing 5mm i.d. 13mm o.d.
- recycled pulley (placing the belt on the outside lets it function as a shaft collar)
- belt
- 2 belt mounts

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

cvoinescu
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Re: Dual Drive Setup (with driveshaft)

Post by cvoinescu » Sun Feb 03, 2013 1:33 am

WillAdams wrote:Is there such a thing as a pulley w/ 2 shaft collar like ends w/ set screws which could double as a coupler?
Not in plastic and aluminum, because there would be no way to slide the plastic over the aluminum insert if it had collars at both ends -- unless one collar was built-in, and the other one press-fit. Metal pulleys are made by turning a piece of MXL aluminum extrusion down at both ends, and press-fitting a flange at one end and a collar at the other end. I see no problem in turning a slightly longer piece to accept collars at both ends, except that it's unlikely that something like that exists as a standard component. I haven't seen anything like that, and I've scoured the internet far and wide trying to find good quality 18MXL pulleys at decent prices. I would have noticed an oddity like that.

I like the idea a lot, with several caveats: 5mm may be too thin and may whip; the pulley/coupler will be hard to find; and don't the newer ShapeOkos have 22mm holes in the motor plates?
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 » Sun Feb 03, 2013 2:58 am

cvoinescu wrote:I like the idea a lot, with several caveats: 5mm may be too thin and may whip; the pulley/coupler will be hard to find; and don't the newer ShapeOkos have 22mm holes in the motor plates?
Thanks!

To make matters worse, closest I've been able to find locally thus far is 3/16.

As an alternative to a coupler one could try grinding off half the motor shaft, grinding a matching flat on the 5mm rod, and using the set screw on the pulley to hold things together (along w/ a shaft collar and bearing at the end to preclude longitudinal pulling and it should hold) --- is the motor shaft replaceable?

Good point about the design change --- the drawing files don't seem to've been up-dated.

I'm going to try the local hobby shops tomorrow. Worst case is I'll have to try 1/4".
Shapeoko 3XL #0006 w/ Carbide Compact Router w/0.125″ and ¼″ Carbide 3D precision collets

cvoinescu
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Re: Dual Drive Setup (with driveshaft)

Post by cvoinescu » Mon Feb 04, 2013 2:21 pm

WillAdams wrote:As an alternative to a coupler one could try grinding off half the motor shaft, grinding a matching flat on the 5mm rod, and using the set screw on the pulley to hold things together (along w/ a shaft collar and bearing at the end to preclude longitudinal pulling and it should hold) --- is the motor shaft replaceable?
The motor shaft isn't replaceable. I'd go for a slightly more complex design rather than grind the motor shaft. I'd put the motor on spacers, standing 30-40mm off the motor plate, and attach the shaft with a flexible coupler. On the shaft I'd have, in order: flexible coupler, bearing (in holder attached to motor plate), pulley, vast expanse of bare shaft across the machine, pulley, bearing (in another, identical holder attached to the motor plate). This seems like the simplest version that can be done with fairly standard components. Also, 1/4" shaft would work just as easily as 5mm, using 1/4" bore pulleys, appropriate bearings, and a 5mm-to-1/4" coupler. That's a big plus in my book.
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 » Mon Feb 04, 2013 2:29 pm

Unfortunately, I didn't have the foresight to order a pair of pulleys, so I'd have the flexibility to try a 1/4" shaft.

If I'm unsuccessful w/ the last 3 local hobby shops and can't find a source for 5mm shafting, coupler and collar.... Edit: I was. Broke down and paid the $7.97 to have a single pulley shipped to me, along w/ some other odds and ends.

I'd still like to work up a design which uses:

- 5mm pulley
- 3/16" shaft collar (and some technique to combine it w/ the pulley so as to function as a coupler --- drill through 4 holes and screw them together?)
- 3/16" rod
- 3/16" flanged bearing
- 3/16" pulley (or, could one sleeve the 3/16" rod and use a 5mm or 1/4" pulley? Looks like there're tubes which would work for the latter)

which I think would be appropriate for the stock size, and should be much less expensive, if the parts could be sourced.

William
Last edited by WillAdams on Tue Feb 05, 2013 1:03 pm, edited 1 time in total.
Shapeoko 3XL #0006 w/ Carbide Compact Router w/0.125″ and ¼″ Carbide 3D precision collets

Tom Smith
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Location: North Vancouver, British Columbia

Re: Dual Drive Setup (with driveshaft)

Post by Tom Smith » Mon Feb 04, 2013 3:48 pm

WillAdams wrote: - 3/16" shaft collar (and some technique to combine it w/ the pulley so as to function as a coupler --- drill through 4 holes and screw them together?)
I used one of these - http://www.pololu.com/catalog/product/1083 - to couple the motor shaft and the drive shaft, it was much easier to fit this into the small spaces I was dealing with than it was a flexible coupler. You could probably bore out one of the sides to accomodate a difference in size between the motor shaft/drive shaft as well.

Tom
_______________
ShapeOko1 191

WillAdams
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Re: Dual Drive Setup (with driveshaft)

Post by WillAdams » Mon Feb 04, 2013 6:30 pm

Thanks!

If I can source the 5mm rod it seems pretty straight-forward:

- use the 5mm rod to align the two pieces
- clamp
- use a drill press to drill a couple of holes
- tap the pulley for threads
- insert screws et voila! instant coupler

but, 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.

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

minorthreat
Posts: 43
Joined: Tue Apr 24, 2012 4:34 pm
Location: Boston, Ma

Re: Dual Drive Setup (with driveshaft)

Post by minorthreat » Wed Feb 06, 2013 8:17 pm

Mcmaster is my general goto for mech parts.

http://www.mcmaster.com/

Rod will save you money vs shaft, and it's generally pretty straight (at least straighter than HDepot rod)

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