Another stepper motor powered rotary table

Having used my 6 inch Vertex rotary for 2 years I wanted to find a better way to mount a chuck that didn’t consume unnecessary Z axis height and with the chuck removed also provide a platform for workholding that was more flexible than just 3 T slots. That went one step further (pun intended) with a desire to speed up manual operation. This is the result, which is as compact as I could achieve and prevents the often-seen massive overhang of the stepper motor hanging off an adaptor tube of some sort. The stepper driver and division controller is from Steve at World of Ward which gives increments down to .01 degrees with standard stepper driver settings.

The design uses an inner sleeve over the existing indexing spindle housing and is located by 3 grub screws that conveniently fit into the existing machined recess in the housing. A slim profile NSK ball race with metal shields provides swarf protection without the drag of rubber seals and which supports an outer sleeve onto which a toothed belt pully is mounted which is fixed by 2 grub screws, these locate into matching dimples in the outer sleeve. The bearing takes about 80% of the small belt pre-tension load, the remaining small radial load is taken by the worm spindle. The drive from the outer sleeve to the worm spindle uses the same keyway as would normally be used to locate the standard indexing handle and the sleeve is located axially using the existing handle hex cap head screw and washer.

I have a strong dislike for unprotected wires as seen on many projects with stepper motors. By chance I found an existing 3D model for Nema 23 size motors that was downloaded for free and sent to a 3D printer bureau. This link will give you a choice of end covers and with a lock type multi-pin connector the electrical connection is robust and can be easily disconnected. **LINK**

After a lot of usage for indexing by degrees and divisions and also for accurate profiling I am pleased with how it all works and would like to thank Steve Ward for all his help with the initial set up.

Edited By mike robinson 2 on 09/01/2023 11:1

The 6 inch mounting plate is 0.8” thick and has 1 central 6mm reamed hole ½” deep (so a dowel wont fall right through) and 42 M6 tapped holes, 2 groups of 12 on 2 different PCD’s, the inner ring of which matches the Pratt Burnerd chuck mounting. The remaining holes are in a grid pattern. The 3 chuck location blocks were doweled in place and the chuck location register diameter machined in situ. This does not necessarily provide centre precision but does provide repeatability for relocating the chuck assuming the adaptor plate has not been removed. Centre accuracy measured at the chuck mounted 5/8" dowel pin was .0002” total indicated runout.

A few examples of the work for my Bolton Marine triple are included. The rotary table together with the DRO fitted to my Tom Senior E type mill (see other album) helps me be both precise and confident enough not to have to mark one part from another. As for speed, a few seconds for an index and your back to drilling another hole.

Profiling and stub drilling centres on the High pressure lower cylinder cover

Low and Intermediate cylinder casting, note the cylinder bleed holes which are angled that exit 3/64" from the cylinder face.

Lower cylinder covers and tooling sleeves to prvent damage to the LG2 bronze

7BA (overlength) test studs fitted

Tapping High Pressure cylinder stud holes 7 BA

Very neat!

Very nicely done. I especialy like the motor conection cover. What are you using to drive the motor and is there a read out. A picture would be nice.

David

Excellent! Are drawings available, would save me reinventing the wheel

Very nice - is the black finish on the adapter plates paint or anodysing?

Superb !

Great pictures too.

Bear........

supb

Thanks to all for the comments.

The controller is from Steve Ward here https://www.worldofward.com/ You can buy a kit or purchase ready made. There is a download section for manuals etc if you wanted to take a look at some of the details. The controller includes a adjustable setting to take into account any backlash.

The black finish is just satin black spray paint on top of a base coat of Upol #8 acid etch primer.

I don't have any drawings beyond my initial design but I will clean them up,check them and will re-post here when available. I am not sure how to share them so your suggestions appreciated.....

Mike a good question! I've been here since 2009 and even back then people were asking to be able to post files formats other than jpegs. You might be able to save your drawings as JPGs and post as photos, but for dxf etc it's best to upload them to a file sharing site such a Dropbox and post a link.

Nice work Mike.

Mike

I too am impressed with your project (and the photographs!), rather than struggle with forum software and its limitations, why not write it up for an article in MEW?

I'm sure Neil and the readers would welcome it.

Ian P

Ian, thanks for the motivation. I will give it a shot and see what Neil thinks.

Mike.

Looks very good. Did you 3D print the back cover or buy it? If you bought it could you point me in the direction of where from. I've found sites where you can down load the files to 3D print it, but as I don't have a printer that's not an option.

Ian J

Hi Ian, as above I downloaded the 3D model of the stepper end cover from here **LINK** this link will give you the available design options then I uploaded to a 3D printing service to generate the model. You can search for such services but here are links to 2 of them https://www.3dpeople.uk/ and https://www.hubs.com/3d-printing/united-kingdom/

Hope that helps

Very nice work Mike.

The motor end cap sounds like a good business opportunity for some entrepreneur, come on Ketan!

I think you can already buy them????

Tony

Well I've searched amazon and eBay to no avail, just one supplier in USA, which isn't going to work with postege and import duty. Anyone know a UK supplier, might be cheaper than getting a one off printed.

https://www.automationshop.co.uk/sy57-back-cover-ip40.html

I have previously designed & printed my own using 4-pin XLR connectors, the two motors I have, both same NEMA size, have diffeent mounting holes, but the one linked to seems to cover that option.

Baldric

thanks