Confusion at very first hurdle


zoebuckle19@...
 

Hello everyone, I'm a new member and I'm really interested in this project, iv a question to ask about the cnc/wemos instructions, the gearing states that I'm suppose to have

GT2 12T, 6.35mm bore, 6mm belt... for the DEC shaft

GT2 16, 6.35mm bore 6mm belt... for the RA shaft

2x GT2 48T, 5mm bore, 6mm belt...for the steppers is this suppose to be the other way around ? As in the 48t for the mount and the 12t and 16t for the stepper motors?

Upon looking online i cannot find 6.35mm 12t or 16t, they all seem to be a 6mm bore, or am I wrong, sorry for the news question, I'm just trying to make sure I understand before attempting a build

Thankyou in advance for any help and info on this


Howard Dutton
 
Edited

On Sat, Feb 12, 2022 at 02:57 AM, <zoebuckle19@...> wrote:
2x GT2 48T, 5mm bore, 6mm belt...for the steppers is this suppose to be the other way around ? As in the 48t for the mount and the 12t and 16t for the stepper motors?
Yes 48t on the mount and smaller pulley on the motor [very very rare that one would want it the other way around but it does happen sometimes.]

Upon looking online i cannot find 6.35mm 12t or 16t, they all seem to be a 6mm bore, or am I wrong, sorry for the news question, I'm just trying to make sure I understand before attempting a build
The often used NEMA17 motors are almost always 5mm and that bore is common due to the 3D printer market.


ssalb
 

Also, check the diameter where you will pot the 48T  pulleys, it’s likely those need the 6.25mm bore. I didn’t pay attention to this with my eq5 and bought 5mm ones - later I had to buy new ones 


Drew 🔭📷🚴‍♂️
 

It would be good to have more information on your mount. At first glance it does seem like you have things backwards. Usually the pulleys are for reduction. The small gears would be mounted to the steppers. The steppers have a 5mm shaft. So your 12T and 16T pulleys would have a 5mm bore. Both of these are available.

Your 48T pulley would have the 6.35mm bore. This is 0.25" which would be matched to the worm gear shaft size. Many worm gear shafts are 6mm, so knowing what mount you have is needed.

The belts would be GT2 6mm width. The number of teeth is calculated by the distance between the two pulleys.


 

This outfit out of Greece has many pulleys in various bore configurations.

https://grobotronics.com/

They were the only ones I found last year that had flanged pulleys in 48T and 60T with 6mm bore.  I think George Cushing used to provide a freebie (if you mailed him the pulley and paid for return postage) and bore out a 5mm pulley to 6mm.


George Cushing
 

Tell us the mount you are converting. 0.25" worm shafts are pretty scarce. 


George Cushing
 

Won't be much meat left on a 12T after it's bored to 0.25" Some filament feeders are made with 1/4" shafts. Is that what you have?


George Cushing
 

I do? Well sure. I invested in 5, 6mm & 0.25" straight flute reamers. Well, O.25" wa inherited from Uncle Henry, who worked at a federal armory established by Geo. Washington after returning from service in the Pacific. It may have followed him home...


Peter Boreland
 

I think you will find McMaster has 1/4" shaft GT2 12t and 16t pulleys. Not sure on the 12t, but that is rather too small I would think? Very fast delivery and a great company.

Peter


Peter Boreland
 

On reflection, I think you have this backward. The small pulley goes on the motor that are mostly 5mm for nema 17. The large pulley goes on the worm which is 1/4" or 6.35mm. 

Peter


Chad Gray
 

12t 5mm bore you can get on AliExpress.


On Wed, Feb 16, 2022, 11:42 PM Peter Boreland via groups.io <pcboreland=yahoo.com@groups.io> wrote:
On reflection, I think you have this backward. The small pulley goes on the motor that are mostly 5mm for nema 17. The large pulley goes on the worm which is 1/4" or 6.35mm. 

Peter


 

On Wed, Feb 16, 2022 at 02:53 PM, George Cushing wrote:
I do? Well sure. I invested in 5, 6mm & 0.25" straight flute reamers. Well, O.25" wa inherited from Uncle Henry, who worked at a federal armory established by Geo. Washington after returning from service in the Pacific. It may have followed him home...
LOL, sorry George if I volunteered you for this.  I thought I remembered a post from you saying you had a lathe and a 6mm bit and you could make quick work of the pulley.  Maybe it was someone else ;-)


zoebuckle19@...
 

Oh I'm sorry you guys I'd only just saw these messages, I dont know how to navigate through the forum properly just yet, I did manage to get the right gears, it must be a typo on the instructions, I dont know if I need to open a new thread about this but is there qnywerw I can find the operating instructions on how to actually use this with stellarium and the onstep app please 


 

On Thu, Feb 17, 2022 at 09:53 AM, <zoebuckle19@...> wrote:
Oh I'm sorry you guys I'd only just saw these messages, I dont know how to navigate through the forum properly just yet, I did manage to get the right gears, it must be a typo on the instructions, I dont know if I need to open a new thread about this but is there qnywerw I can find the operating instructions on how to actually use this with stellarium and the onstep app please 
Zoebuckle - I made a first attempt reply to your other thread regarding using the app and connecting with Stellarium
main@onstep.groups.io | Step by step guide for interfaces ??


ybaransky
 

What are good sources for all the parts other than the stepper motors here in the US, namely the pulleys and belts, small plates to make standoff parts to attach things to mounts, machine screws to attach motors and plates to mounts, cases to enclose the electronics,  and so on.  When you order the wrong component from Asia, shipping time becomes much more important for the replacement. 
I thought the resource page here was a great idea, but it is not getting populated.
thx
-yurij


Ken Hunter
 

I agree... There should be a lot more participation on the Resources page. You can find a lot of
the parts you need on Amazon and eBay. Mouser will sell you a single 10 cent item though you
will have to pay for the expensive USPO or other shipping method. I keep a small stock of parts
as does George Cushing, Some vendors from China advertise optional fast shipping for a small
additional fee and some of them have Stateside "middle-men" that can get you parts in a week.
You have to read the full shipping details on Ali-Express or the other sites.

You can start a new subject anytime but I suggest something like "Resources - 5-way switch"
or something similar to get the  ball rolling.

I mentioned the Lathe and 6mm drill for opening up the 5mm to 6mm gear holes. Again, it
is the shipping costs that all add up.

What parts are you missing? I have button Caps of nearly all colors including the 5-way switch
cap that AFAIK are not available unless you 3D print your own.


Peter Boreland
 

McMaster has belts and pulleys for 1/4" bore. https://www.mcmaster.com/pulleys/for-belt-trade-size~gt2/

Being able to get a belt quickly is a major convenience, as I could not be quite sure what sizes I needed.

You have to buy from George Cushing or china for the 5mm bore stuff.

Peter


George Cushing
 

Yes, I think I made that offer when this was a smaller club. Not sure it's worth the $4 out and $4 back shipping it would cost these days. MPJA.com has wheels in 0.25" at "fair" prices. 


George Cushing
 

Stock Drive Parts for pulleys and belts. For aluminum eBay. In addition to pulleys, project boxes and steppers, MPJA.com or StepperOnline. 

I have most of the PCBs, passive components, semiconductors to build the controllers, project enclosures and a modest selection of belts and pulleys. 


Robert Benward
 

I found these guys to have a small supply of pulleys and a very good supply of GT2 belts in 2mm increments.  They have 1/4" bore (6.35mm) and 60T.  Some are in 9mm wide, which can still be used with 6mm belts.  Pretty fast delivery considering they are in China.  I think I got most of my pulleys from Amazon though, but my belts from here.

https://www.robotdigg.com/product/475/24-Tooth-GT2-Pulley

Boring holes:  I recommend a precision reamer to enlarge holes.  Drill bits can vary and gouge the sidewalls and they are not known for super accurate holes.  Reamers come in tolerances above and below the target size.  Some can be had at exactly target, and others 0.0005" under or over.  This will keep the wobble to a minimum, but they are not cheap.  Use letter or number drills, or metric and drill under as close as you can then use a reamer.

https://www.mcmaster.com/reamers/system-of-measurement~metric/reamer-size~6-mm/

The one above is 0-0.005mm tolerance (0.2mil).  $24

Bob

P.S.  Found this, dual harmonic drives mounted 90deg to each other.  50:1 reduction.  A mini equatorial ready to go!
https://www.robotdigg.com/product/1978/Harmonic-drive-4th-and-5th-AC-rotary-axis-for-CNC-machine