Fitting a Sherline CNC indexing table on Super 7

[Alan Wood 4Participant @alanwood4]

Being a fan of the clock maker William Smith, I was interested in his use of the Sherline CNC table for indexing the Myford lathe.

While Bill shows its use there is little constructional detail of how to actually do this in his videos and books and this would have been no value anyway for me as I have a large bore S7.

I had purchased a S7LB hand crank and used this as a starting point for dimensions for the mandrel sleeve to fit into the rear of the headstock. The sleeve has a 7 degree taper grip on one end and the interface to the Sherline uses a standard 18mm collar from Bearing Boys bolted to the Sherline table.

In order to get the collar exactly centered I made a stepped bush to fit the table centre hole and with an OD of 18mm to snuggly fit the bearing collar. This was centre drilled 6mm and held in place while I drilled and tapped the collar onto the table.

The retaining shaft is a 6mm rod tapped and Loctite into the taper expander cone. The cone has a piano wire cross pin to stop rotation in the mating sleeve. Quad lateral slots are cut in the sleeve to match.

The shaft pulls the cone into the sleeve, expands the sleeve which in turn grips inside the head stock. This also pulls the sleeve into the Sherline table collar. There is a grub screw on the collar for added grip if needed.

The image below shows the parts involved.

The upper item is the sleeve.

The centre line shows the retaining shaft with taper cone and knob.

The three lower items are just for reference being the Sherline centre boss as supplied, my centering boss and an example collar.

The assembly is fixed with a simple aluminum bracket to the side of the S7 tool tray to stop rotation. This is the last thing fastened in place once the sleeve and table are mounted so there is no stress on the table.

I have done numerous checks on the repeatability of the indexing and find it excellent.

The Sherline is a wonderful piece of kit allowing any division by degrees or steps up to 999. It also has programming for multiple process steps.

If this is of interest to anyone I can do a more detailed write up with drawings and pictures.

Alan

[Alan Wood 4Participant @alanwood4]

Myford Super 7 Large Bore with CNC Sherline Indexing table

[Neil WyattModerator @neilwyatt]

Hello Alan,

That could make an interesting write up for MEW.

Neil

neil.wyatt@mytimemedia.com

[Michael GilliganParticipant @michaelgilligan61133]

Very neat, Alan

MichaelG.

[Another JohnSParticipant @anotherjohns]

Not to take anything away from Alan's work, but W. R. Smith of clockmaking fame has the same thing (but for a Sherline lathe) on the cover of one of his books; this should be a link to it:

**LINK**

I really like the Sherline company – they seem to be proactive and competing and (along with Taig/peatol) are somehow surviving as a western country building machine tools.

I've got one of their CNC rotary tables on my smaller CNC mill, and I'm thinking of updating my Unimat SL CNC lathe to a Sherline CNC lathe, but I use it mainly for demonstrations, and don't know if it is "worth it" in time and money.

Here's a link to my CNC blog – search for "Sherline" or "Unimat" if you are at all interested. **LINK** – John.

[MuzzerParticipant @muzzer]

"W. R. SMITH, BSME, FBHI, FNAWCC, CMC, CMW, CMEW, W4PAL".

Haha!

He's a radio amateur (W4PAL) but no idea about the rest.

Edited By Muzzer on 14/02/2015 13:59:49

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Muzzer on 14/02/2015 13:59:03:

… no idea about the rest.

.

FBHI is Fellow of the British Horological Institue.

MichaelG.

[Neil WyattModerator @neilwyatt]

That was the only one I recognised, but some serious digging gives:

Bachelor of Science in Mechanical Engineering

Fellow of the National Association of Watch and Clock Collectors

Certified Master Clockmaker

Certified Master Watchmaker

Certified Master Electronic Watchmaker

I think he must be into making clocks.

Neil

[Alan Wood 4Participant @alanwood4]

Hi

This was my first post and I think I should apologise for not making myself clear.

The idea for using the Sherline Table came from William Smith and featured in his various documentation. Bill is a very elderly and learned gentleman for whom I have the greatest of respect and reverence. There was no intention to infer directly or indirectly that the idea was mine.

The project and the subsequent post was an attempt to bring his concept to a wider audience and offer a practical example of how it could be implemented to engineers who had the vision to see its merits but perhaps lacked the small print of how to do it.

Again I apologise for not making this sufficiently clear

Kind regards

Alan

[Neil WyattModerator @neilwyatt]

No apology needed Alan, I thought the first few sentences of your first post make it quite clear you aren't trying to pass his idea off as your own, but that you were filling in the gaps for those who might like to try a similar setup.

Neil

[Another JohnSParticipant @anotherjohns]

Alan – agreed – I guess that I should say that I'm interested in making clocks – but need to retire, I guess. Went through Greenwich and saw Harrisons' clocks back in December when visiting the UK. Fascinating stuff.

I'm amazed in part by the interesting equipment clock makers use for their work; it's a very different mind set than the usual (and, my focus) locomotive building. It's like learning a new language.

Apologies if my post wandered away (and, took away from) your initial words – many interesting ideas to be found, and a day without learning/discovering something is a boring day, indeed!

John.

[Alan Wood 4Participant @alanwood4]

Thanks John, no problem.

Clockmaking intrigues me, hence my need to get the resources in place. I have also followed Bill's idea and made a conversion block to put the Sherline headstock assembly on the Myford vertical slide for gear cutting. I am hoping to see him at the National Convention in Chattanooga in June.

Harrison's stuff is astonishing. I have a couple of ship's chronometers which I rashly bought after having been blown away by the internals.

I looked at your CNC site and there is some nice stuff. In my working life we designed and manufactured radio communication equipment and I dumped a Bridgeport CNC lathe with Haidenheim controller on the metalshop and told them to learn how to use it to mill our enclosures. They had never seen or used one before …. didn't get a Christmas card that year. Within a few months we were producing stuff and later added a second Hardinge with Fanuc. Product was designed initially on Alibre CAD and later Solid Edge. We used SprutCam as the interpreter driver to program the machines. Those guys ended up producing some really complex stuff and in big numbers.

Anyway thanks again.

Alan

[KWILParticipant @kwil]

An alternative fixing solution would be to make the location collar part-split, using the table centre hole, retaining to the table by a short stud through the table, much as the OP has shown, but to grip the parallel ground end of the lathe spindle for retention. No need to make the expansion sleeve etc.

I have used this approach to retain a normal Myford dividing head in the same position.

Edited By KWIL on 16/02/2015 12:22:10

[ianjParticipant @ians]

This thread inspired me to build a stepper motor spindle indexer for my Myford ML7RB lathe. The stepper motor is geared down via a 30:1 worm/gear removed from a skipped motor. I built the stepper motor controller some time ago from the information found here:-**LINK** and use it on my adapted rotary table,

Ian

[Alan Wood 4Participant @alanwood4]

Nice job Ian.

Certainly cheaper than the Sherline table.

Do you get any backlash ?

Alan

[ianjParticipant @ians]

Alan.

There is a little back lash, but no more than on my rotary table. It's not a problem as long as if you overshoot you rotate in the opposite direction half a turn and then rotate back to the position originally required. There's something very satisfying building a usefull tool out off scrap ( recycled ) parts.

Ian

 

 

 

 

 

Edited By ian j on 27/02/2015 18:02:33

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