[kolias]

What is the reason to have stepper motors with dual shafts? Looking online there are not a lot with dual shafts
Thanks

[phomann]

What is the reason to have stepper motors with dual shafts? Looking online there are not a lot with dual shafts
Thanks

The main reason was to attach an encoder to the stepper on a handle for manual adjustment.

Note that it should not be used as a drive shaft as the bearing at that ind is not up to it.

Cheers

Peter

[kolias]

The main reason was to attach an encoder to the stepper on a handle for manual adjustment.
Note that it should not be used as a drive shaft as the bearing at that ind is not up to it. Cheers Peter

Thanks Peter, looks like "steppersonline" is the best place so far to buy motors with digital drivers but when I asked about dual shafts he said No. I normally use dual shafts to attach a home made hand wheel for adjustments on the Y axis since I drive it slaved to A axis but I can manage without the hand wheel. I also asked if he can supply a BOB with a parallel port and he said No, so I will source the BOB from others.

[joeavaerage]

Hi,
it matters less where you buy than selecting the right ones. To many stepper are made with high inductance and are poor for CNC. The high inductance ones
tend to have the highest torque, which is what attracts buyers and can be made cheaply. Low inductance steppers tend to have lower torque despite having higher current
and be more expensive....but are hands down better than high inductance types.

For 23/24 size stepper look for 1mH-2mH, 1mH preferred and reject anything over 2mH.
For a 34 size stepper look for 2mH-4mH, 2mH preferred and reject anything over 4mH.

Craig

[kolias]

Hi,
it matters less where you buy than selecting the right ones. To many stepper are made with high inductance and are poor for CNC. The high inductance ones tend to have the highest torque, which is what attracts buyers and can be made cheaply. Low inductance steppers tend to have lower torque despite having higher current and be more expensive....but are hands down better than high inductance types.
For 23/24 size stepper look for 1mH-2mH, 1mH preferred and reject anything over 2mH.
For a 34 size stepper look for 2mH-4mH, 2mH preferred and reject anything over 4mH. Craig

Many thanks Craig, I knew about the inductance property, for NEMA 23 what I get is 3.8mH the lowest but I will look again if I can find ones with a lower value. But I also think the motor driver should be "Digital" and the majority on the web they just say "Motor Driver".

[joeavaerage]

Hi,

for NEMA 23 what I get is 3.8mH the lowest

That's not the worst I've seen but still double what you want. Keep looking, don't settle for anything over 3mH at the outside, and for my money I would not get anything over 2mH.

Peter Homman responded to your post, and he sells steppers, including this one which is 570 oz.in and 2.1mH, would be a very good candidate.

https://www.homanndesigns.com/index....30689e11p2fcm5

But I also think the motor driver should be "Digital" and the majority on the web they just say "Motor Driver".

They all are. Some are more sophisticated than others, but its small beer by comparison thre the stepper. Choose the driver with the highest possible in put voltage,
I'd suggest no less than 80VDC.


Craig

[kolias]

What is "D-cut Shaft Length: 20mm" ? I dont understand the D-Cut what it means

[phomann]

What is "D-cut Shaft Length: 20mm" ? I dont understand the D-Cut what it means

It’s the “flat” that they put on the shaft for the set screw to fasten against.

Cheers

Peter


Sent from my iPhone using Tapatalk Pro

[kolias]

It’s the “flat” that they put on the shaft for the set screw to fasten against. Cheers Peter Sent from my iPhone using Tapatalk Pro

I didn't know the "flat" is called D-Cut, thanks

[kolias]

Craig you are talking about 570 oz.in motors and 80VDC max drivers, all my previous machines had 280 oz.in motors and 50VDC max drivers and never had a problem moving my 3/8” thick aluminum gantry with a water cooled spindle. I just cant imagine where you will need anything more than what I used. I understand you are using your machines to cut steel/SS and perhaps in this case the numbers you mentioned are more appropriate, mine are designed for hobby/light commercial use.

I also know about the “homanndesigns” wonderful site but he is in the “southern hemisphere” and shipping to “northern hemisphere” will be quite expensive.
Nicolas

[joeavaerage]

Hi,
firstly the higher voltage is about speed WITHOUT missing steps. 50VDC is now entry level at best, do yourself a favour and get high voltage drivers, they cost but pennies
more than lower voltage units so you might as well have them. If 280oz.in is good enough then carry on but if you ever start losing steps you'll think 'I should have spent and
extra $10 and got those bigger ones'.

“southern hemisphere” and shipping to “northern hemisphere” will be quite expensive.
Nicolas

Ask him. Last week I had some Canadian dude saying that I (in New Zealand) was closer to China than he was......he was wrong...not much in it, but he is 500km closer than I am.

Craig

[kolias]

Hey Craig, I thought you will remember who I am, the “Canadian dude” is me, Forum name is “kolias” real name is Nicolas. You have helped me in the past a lot and I appreciate you knowledge.

I haven’t purchased anything yet but looks like what I will buy is a “set” with no options to ask for any changes. I’m still looking and perhaps I may find a place which will give me a choice.
Nicolas

[joeavaerage]

Hi,
yes I knew it was you....just trying not to rub it in.

Recommend that you get 'good' steppers and drivers, they will last many years, the modest extra you would pay for good as opposed to average will be rewarded over and over again.

Craig

[kolias]

Hi Craig, from the attached picture which of the 2 stepper motors is better? The second one it says to wire "Bipolar (Parallel)".
I know they are not big to your standards but for my needs they will do the job. Both cost the same and not sure I will buy them but for comparison I would like to know.
Thanks
Nicolas

[joeavaerage]

Hi,
the 3.6mH one should be disregarded, its inductance is just too high.

The second on with 2.2mH wired bipolar parallel is best, 2.2mH is fair, but only fair.

Craig

[kolias]

Hi,
the 3.6mH one should be disregarded, its inductance is just too high. The second on with 2.2mH wired bipolar parallel is best, 2.2mH is fair, but only fair. Craig

Thanks for your time Craig
Nicolas