[lucas]

Very nice build.

How did you make the text on the keyboard?
I have the same and don't know how to do it: nice and finger resistant.

Will you add a cable strain relief?

[artificerjon]

Thank you for all your kind remarks about my attempt at the indexer. I have a drawing of the adaptor I made which I can send in various formats and can also point anyone who is interested at the motor supplier and driver supplier. It would be appropriate to do that off forum so if you let me have your email address either via a private message or leave your email address here I will get back to you.

[Georgie]

Thank you for all your kind remarks about my attempt at the indexer. I have a drawing of the adaptor I made which I can send in various formats and can also point anyone who is interested at the motor supplier and driver supplier. It would be appropriate to do that off forum so if you let me have your email address either via a private message or leave your email address here I will get back to you.

HI,
I'm interested to know if anyone has made any PCB's for the electronics and keypad for Steves project and can I purchase a set anywhere ?

I have made my 4th axis which I will drive using my CNC router but I also want to use it with a hand held controller on my bench mill.

It uses a 3" chuck driven by a Nema23 stepper using a ratio of 6:1 drive pulley.

Hopefuly someone can help.

Thanks

George

[arvidj]

...

The motor is a NEMA 17 sized 1.8A per phase unit I obtained from China via eBay ...

...

The drive unit is made by UI Robot Technology in China, another eBay purchase, and is ideal as this 2A unit mounts directly on the back of the NEMA 17 motor.

...

A really nice job.

Can you provide more information about the motor vendor you used on eBay and especially the drive unit vendor? I like the idea of having the controller right on the back of the motor ... assuming it is not in a liquid cooled environment or where chips might be a problem ... but was not able to easily find the vendor.

Thanks,
Arvid

[artificerjon]

In answer to the questions which have arisen from my post about the completion of my indexer :

1) The motor supplier has similar motors available on eBay, see : CNC Nema17 for 1.7A, 3400g.cm, 40mm length, 4-Lead 2 phase Wantai Stepper Motor | eBay though if you do an eBay search for NEMA 17 a number come up including both 1.7A and 2.5A per phase units.

2) The driver unit supplier also has more available on eBay, see : Stepper Drivers, Stepper motors items in stepper driver store on eBay!.

3) The couplings came from Arc Eurotrade, see : Oldham Couplings - Arc Euro Trade


Usual disclaimer I have no connection with any of these suppliers other than as a satified customer.

If you want a copy of my drawing of the motor/table adaptor send me your email address via a private message & I will email the drawing to you.

[artificerjon]

Following a number of requests I have attached the drawing in pdf format of the adaptor I designed & made to join the NEMA 17 motor to my Sherline rotary table. It also includes details of the modifications I had to make to the table worm housing. I ensured concentricity of this register by turning between centres with the centres resting in the I/D of the sealed bearings (having first removed the worm shaft). Sherline advise you to NOT remove the housing but I guess this is for their protection against those who would do this then complain to Sherline if the adjustment of worm & wheel is not all it should be !!

The 10mm slot in the adaptor is there to give access to the coupling clamp screws and I assembled the adaptor so that the slot is at the bottom.

In order to fix the motor driver to the motor back face I had to replace the original 3mm motor assembly screws with longer ones. When tight these should leave about 3 to 4 mm of thread inside the hole on the motor mounting face to allow room for the screws which attach the adaptor to the motor.

The housing assumes the use of the 19mm O/D coupling I purchased from Arc Eurotrade, details on the forum. I used this as it was the smallest I could get. Unfortunately I had to purchase the end parts with 4mm & 6mm bores then bore & ream them out to 5mm & ¼” I/D to suit the motor and table shaft. Not shown on the drawing is a spacer which goes between the back of the coupling on the table shaft and the face of the inner race of the bearing. Mine came out at 0.28” length and was ½” O/D x ¼” I/D (sorry to mix metric & imperial dimensions). This is needed to eliminate worm shaft end float. To use this spacer the plastic coupling disc needed a hole boring in its centre the same diameter as the width of the cross slots in the disc, this is to accommodate the head of the button head screw which holds the coupling and spacer together. I found the screw needed a small amount machining off the O/D of the head to ensure the disc had some room for radial float.

When assembling the coupling, having first attached the adaptor to the table, slide the spacer on to the worm shaft followed by the coupling half then insert the screw into the end of the shaft (the end of the shaft should lie just BELOW the face of the coupling so that the screw can pull the coupling & spacer tight against the face of the bearing inner race. To tighten the coupling onto the shaft alternativly adjust the coupling clamp screw and the shaft end screw untill both are fully tightened, the coupling is tightly clamped to the shaft and the coupling and spacer are tight against the bearing.

These details and drawing are offered without any warrenty as to their suitability, the use of the details and/or drawing are at the users risk.

[arvidj]

I want to thank you for all of the detailed information you have provided.

[arvidj]

Would anyone care to speculate as to the recommended torque requirements are for an 8 inch rotary table? It would seem that with a 90:1 worm gear ratio lots of torque would not be required, but I have no idea what a realistic value would be.

I would prefer to use a NEMA 23 motor rather than a 34 but want to make sure I have enough umph to make it work.

[Georgie]

I plan to build this indexer. It's just what I'm looking for.

I have already completed my 4th axis and have it running under mach 3 on my router machine.

I want to make it dual purpose and use it on my vertical mill. The gear ratio is 6:1. 10tooth on the stepper and 60 tooth on the chuck drive. Do I need extensive modifications to the code so I can run the indexer with my set up.

Thanks

George

[kwackers]

Hi George,

It should work fine. If you're running a half step motor then that's 6*400=2400 steps per rev.
So just enter 2400 in setup ("Set Steps per 360").

Cheers
Steve

[Georgie]

Hi George,

It should work fine. If you're running a half step motor then that's 6*400=2400 steps per rev.
So just enter 2400 in setup ("Set Steps per 360").

Cheers
Steve

Great, thanks Steve. Methinks it's a trip to Maplins this weekend, they have some pre-sensitised copper clad board so I might have a go at making the PCB.

George

[RomanLini]

For metal machining with a size 23 stepper you would do well with about a 4mm lead screw, so for each motor revolution the cutting tool travels 4mm.

If the worm gear is 90:1 at 50mm radius (100mm diam) it travels 314mm per 90 rotations, or about 3.5mm per motor rotation. So for light machining of metals you would probably be ok with jobs up to about 100mm diameter and maybe more, but of course it depends on the actual motor and motor driver, and also the cutting tool and material. That is also worst case, ie the tool moving at 90 degrees to the table.

Personally I think you would be ok, but that's just a guess based on a very rough calc. Maybe someone with actual experience using a size 23 motor on a 90:1 table can offer feedback?

[allaces]

Steve,

I'm looking for a stand alone handheld controller like this for indexers I sell. Would you consider making them for money?

Please respond to [email protected]

Thanks,
Ray

[allanwinks]

Hi all
I am completely new to CNC and have started to build a router when i came across Steves wonderful digitiser. I have read my way through all the posts and wondered if anyone has a comercial PCB for sale? I have made them before but my success rate isnt high.

[Georgie]

Does anyone have a spare PCB for the Rotary indexer, failing that did anyone use Mach3 to cut one and would they care to share the code?

Many thanks

George

[Me2]

G’Day All,
I have been running my rotary indexer on my Rotary Table (ratio 90-1) for the last 18 months with no problem. Needed some more power so upped the driver capacity and added on a larger power supply still running great.
I acquired a dividing head recently (ratio 40-1) and added on the stepper with a ratio of 1.75 – 1 through the timing pulleys. This brought the ratio up to 70-1. Setup the second profile with that number running in half stepper mode.
When setting up to divide say 24 divisions the screen read out goes – 0, 14.02, 29.02, 45.00, 59.02, 74.02, 90.00 etc. The same sort of thing happens in degree mode using 15 degree steps. The strange thing is if I change the worm ratio back to 90 it works perfectly. I am absolutely stumped about what to do. I’ve reset the factory defaults no change I don’t know what to do next. I’m using the Hex Code 2.11. Has anybody else experienced this problem? If you have, what did you do to overcome it? If all else fails I’ll try programing another chip and see if that makes any difference.

Cam

[arvidj]

G’Day All,
I have been running my rotary indexer on my Rotary Table (ratio 90-1) for the last 18 months with no problem. Needed some more power so upped the driver capacity and added on a larger power supply still running great.

Cam

Sorry, not an answer but a question.

What size rotary table do you have?

What size and torque motor did you have ... i.e. the one that appears to be too small?

What size and torque motor did you upgrade to ... i.e. the one that appears to be an adequate size?

And possibly an answer to you question. ... Look back thru this thread as I remember seeing a similar situation discussed and Steve explaining what is happening.

If I recall correctly the "display strange numbers" has to do with the internals software keeping track of "position" as one of 36000 discrete positions ... 360 degrees with .01 degree resolution ...

... the software doing integer math and not floating point math ... i.e. the concept of a value ... even intermediate values in any calculation ... having something other than zeros to the right decimal does not exist ...

... and some rations having "nice" numbers when integer math is taken into account ... i.e. 36000 divided by 90 is 400 ... a nice whole number that fits well with the integer math concept ... but 36000 divided 70 is 514.2857142857143 which is a number that does not fit well with the integer math concept ... and what you see is the byproduct of arrangement.

Arvid

[kwackers]

Sounds like you're using an older version of the firmware. If you trawl back through the thread you'll see someone else had a similar issue which I looked into.

Turned out there was a bug in the display routine - the position is correct, it's just not reported correctly.
I just checked on mine (to be sure) and with a ratio of 70:1 the position is correctly reported.

You could just ignore it, as I said the actual position is correct, failing that you need to reflash the chip with the latest firmware and it should all be good.

(I'm fairly sure that versions of the firmware that require you to enter the number of steps per 360 degrees work correctly, but as I said if you trawl back through the thread you should find the point the bug was fixed)

G’Day All,

When setting up to divide say 24 divisions the screen read out goes – 0, 14.02, 29.02, 45.00, 59.02, 74.02, 90.00 etc. The same sort of thing happens in degree mode using 15 degree steps. The strange thing is if I change the worm ratio back to 90 it works perfectly. I am absolutely stumped about what to do. I’ve reset the factory defaults no change I don’t
Cam

[gandalf1]

Change your belt drive to a different ratio, 90:40 and you should get back to the original setting.
John.

[Me2]

Thanks Steve,
The latest Hex Code (2.12) is post 128 for anyone else looking for it.

Cam