Rotary table indexer

Jimbojones

Active Member
#2
Was wondering how your project turned out. I have a controller from Sherline that runs a small table (4") but would like to build something with a larger motor for larger tables e.g. 6 or 8"
 

Johnwa

Ultra Member
#3
I’m patiently waiting on some timing belts from China. I thought I ordered them early enough to be ahead of the Xmas rush, but apparently not.
 

Jimbojones

Active Member
#4
hmm...my stuff from china has been taking 4-6 weeks for "bigger" things and sub$10 parts taking up to 3 months...you may have some more waiting to do. Still am eager to see how it turns out.
 

Bofobo

M,Mizera(BOFOBO)
#5
Same problem with shipping delays here. Not just china either, although they are slower, i waited 2+ months for a letter mail from the UK
 

Jimbojones

Active Member
#6
Had an order that came USPS/Canada Post took 5 days to get from ON to here after it left Customs....yet one of my suppliers shipped goods from India in 3 days via DHL and didnt even pay express service.

Hey John: any idea what capacity the stepper you're using in conjunction with the size of table you want to mate it to? I realize it doesn't take a bunch of power to turn a table but I know the Sherline I have lists 50lbs horizontal and 30lbs vertical...having that kind of mass on the table would cause some drag on the drive and I'd want to keep the stepper relatively small so it doesnt impede mounting the rig to the table...but big enough that you don't fry it.
 

Johnwa

Ultra Member
#7
Most if not all the spindle and rotary table drives I’ve seen use a medium sized NEMA 23 — 300 oz.in or so..
I’m planning on a pulley driven spindles, as my goal is an indexer for gear cutting so there won’t be any significant weight involved.

You can attach any driver that accepts 5volt signals to the electronic indexer so there really is no real limit on stepper size.

I’ve put a Pololu 2amp drive inside the case, if it isn’t enough I’ll use a bigger external driver.
 

Colten Edwards

Fabricator
Premium Member
#8
one thing I found when ordering from china, is that if you send them to a stateside location, you can have them extremely quickly. I used to work for a company that had a office in Paducah,KY. I was using it to send parts to that I couldn't have sent to Canada, and then having that office forward them. I had ordered some china parts, and forgot to switch addresses. within 2 weeks I had my parts in the Canadian office. I did this quite a few times and it was consistant.
 

Johnwa

Ultra Member
#9
I just got my refund from aliexpress. The belts were shipped through “Yanwen Economic AirMail”. Between aliexpress and Amazon I’ve had about 10 orders shipped through them. Every single one never arrived on time.
OTOH I’ve already received items ordered in January through other shippers.
 

Johnwa

Ultra Member
#11
Attached are pictures of my index controller that I brought to the last meetup IMG_0522.JPG IMG_0523.JPG . I had an arduino Pro Micro so I used it. A nano would work just as well. Both of them have standard pin spacing which makes it easier to connect the keypad. I'm using as 18V lithium supply so I used an 8V regulator to drop the voltage to the arduino.

I used a 330 oz-in stepper and a pololu driver. The pulley ratio is 4.2 and I'm using 16 microsteps for 3200 steps per rev. These have to be entered as integers but since they are multiplied together, I entered a table ratio of 42 and 320 steps. With a step delay of 500 usecs, it has enough torque that it is difficult to hold the spin index wheel tight enough to get it to miss steps. With a step delay of 250 usecs I'm pretty sure it missed an occasional step when starting to move.

I've also attached a picture of my 18V powerpack. I found the 3D stl file for it at https://www.thingiverse.com/thing:352094

Detailed assembly instructions for the controller can be found at http://www.homemodelenginemachinist.com/showthread.php?t=26744
 

Attachments

Susquatch

Well-Known Member
Premium Member
#13
Attached are pictures of my index controller that I brought to the last meetup View attachment 3047 View attachment 3048 . I had an arduino Pro Micro so I used it. A nano would work just as well. Both of them have standard pin spacing which makes it easier to connect the keypad. I'm using as 18V lithium supply so I used an 8V regulator to drop the voltage to the arduino.

I used a 330 oz-in stepper and a pololu driver. The pulley ratio is 4.2 and I'm using 16 microsteps for 3200 steps per rev. These have to be entered as integers but since they are multiplied together, I entered a table ratio of 42 and 320 steps. With a step delay of 500 usecs, it has enough torque that it is difficult to hold the spin index wheel tight enough to get it to miss steps. With a step delay of 250 usecs I'm pretty sure it missed an occasional step when starting to move.

I've also attached a picture of my 18V powerpack. I found the 3D stl file for it at https://www.thingiverse.com/thing:352094

Detailed assembly instructions for the controller can be found at http://www.homemodelenginemachinist.com/showthread.php?t=26744
I'll find my way through your post in due time. I do like the idea of an electronic indexer.

In the mean time, I noticed that you used a Makita 18v Tool battery. My big 8" Meade LX200 telescope is also 18V, so I did the same thing. But I didn't make a 3d printed connector. I just bought their cheapest 18V tool. It happened to be a flashlight. I ripped it apart, made an epoxy plug lid for it that included a regular 2 pin socket, and it has worked great ever since.