renovating a rotary table

[ian weeks 1Participant @ianweeks1]

Dear All , Some advice needed. Some years ago I was given an 8" rotary table by a friend who had replaced it with a shiny new vertex model .It came with the warning that it was solid but a bit "uneven". I have not needed to use it till recently when I discovered that the 120deg holes I was spotting were more 118-122 spacing. There is backlash but the markings seem very well and evenly marked . I had thought I had been careful about the backlash but it seems I will have to adjust this out if I can . I do not know the manufacturer[?Indian] and have no manual. I cannot identify how to adjust for the back lash.Any advice would be appreciated[ If it needs tota stripping no matter it owes me nothing and might be an interesting project-if it ends up dud so be it -Ian

[ian weeks 1Participant @ianweeks1]

[Les Jones 1Participant @lesjones1]

Hi Ian,

There was an article in MEW No.181 (Oct 2011) titled "Improving a low-cost rotary table" that may help you. The construction of your table is probably different but it will probably give you an idea what to look out for.

Les.

[KWILParticipant @kwil]

Whatever you find, remember to always advance in one direction only to minimise backlash effects. If you overshoot, back off some distance and then approach again from the original direction ONLY.

[JonParticipant @jon]

Agree with that Kwil, backlash wont make a scrap of difference that way.

If you think logically as i do this for something else i wont mention. Soon as the play is taken up, the backlash is taken up and will perform as if theres none.

Ian i think the graduations will be pretty accurate, make sure the handle ends up in same position every indexing.

[Gone AwayParticipant @goneaway]

If the backlash is entirely caused by the radial separation adjustment of the worm/wheel then advancing in one direction only will deal with it (although you may as well adjust it to minimise it consistent with free turning). Same situation/technique as backlash in a milling table feed.

If (as has happened to me in the past) you have axial play in the worm, you will find that minimising backlash effects as above will not effectively deal with the problem and you should track down and fix the cause.

[ian weeks 1Participant @ianweeks1]

dear all , thank you for your helpful advice . yesterday took the backplate off and inspected the worm main gear and worm shaft . Play was in the worm shaft. the handle end had been fitted with a detent and division plate . with the detent arm 'nipped between 2 nuts. was a simple task to adjust these to take up back lash and now very smooth. also with aid of Myford oil gun gave the oiling points [and the room /my shirt/ most of the garden] a hefty dose and this had a magical effect. Only down side was put back on before counting teeeth on main gear. when I get a chance will do so . Thanks again Ian

[Les Jones 1Participant @lesjones1]

Hi Ian,

why not just look how many degrees are marked an the scale on the handwheel and divide this into 360. An alternative is to note how many degrees the scale on the table moves fo one revolution of the handle.

Les.

[ian weeks 1Participant @ianweeks1]

Dear all

Thank you for yor helpful replies .Yesterday had a few spare minutes so a light touch with a wire brush and some paint and its as good as new . The ratio of worm to wheel is 1:72 and I have 4 division plates which I think cover the divisions as supplied by the cincinnati company for their tables [but mine is a 715e 8 inch as supplied by various indian manufacturers] The dividing attachment and plates appear original [not bad quality but definitely not up to my theil] However the fingers are missing [or perhaps never existed]. So last 2 tasks are to fabricate some fingers and work out suitable mounting sleeve and to track down a printable dividing table for 1:72 ratio and laminate it .I know I can do each number from scratch but I'm lazy and the table that came with the Theil Is laminated and hangs on the machine- soo handy. I have found a table for 15 and 18 holes but not for those I have – any pointers to helpful sites would be appreciated [ Also if I have to do it myself will have to learn to use a spread sheet and that is what my at presenly t absent offspring are for!] Regards Ian

[Michael GilliganParticipant @michaelgilligan61133]

Ian,

If you decide to go the Excel route; this looks a good place to start

http://www.ameng.com.au/files/dividing%20head%20calculator%2040%20to%201%20ratio.xls

it is currently set for 40:1 and is protected … but the instructions for changing the ratio are included.

MichaelG.

 

I see that the Adverts are intruding again … Apologies if I caused that by pasting a long hyperlink.

Edited By Michael Gilligan on 04/04/2012 08:46:42

Edited By Michael Gilligan on 04/04/2012 08:51:21

[Michael GilliganParticipant @michaelgilligan61133]

For info …

I have just looked at the html for the page

That hyperlink in my previous post is at least 12 characters too long for the layout.

Could the site developers please look at allowing word-wrap for hyperlinks?

MichaelG.

[Martin WParticipant @martinw]

Ian

I have written an Excel programme that generates the division table which shows all the available division ratios for a set of plates for any table. Basically you input the Division ratio of the table in and the hole counts from the plates, it does the rest and presents you with a table that can be printed out. Alternatively it can be limited to just one row so that it displays all combinations that provide a required division ratio. For each available ratio it displays the number of complete turns plus the plate hole increment.

If you would like a copy then please pm me with your email address and I will get a copy to you. Due to current commitments it will probably be after Easter.

Regards

Martin

[Les Jones 1Participant @lesjones1]

Hi Michael,

You do not have to make all of the hyperlink visible. It can be hidden behind any section of text. For example Michael gilligans link Thyis should take you to your link.

To do this type in the text you want to click on to go to the link. Highlight this text. (Drag th curser accross it with the left mouse button pressed.) Click on the link button and put the URL in the URL box.

Les.

[Michael GilliganParticipant @michaelgilligan61133]

Les,

Thanks for the advice … I will try that next time.

Somewhat reluctantly however; as I generally prefer to see hyperlinks disclosed in full, for the sake of security.

​MichaelG.

[Gray62Participant @gray62]

MichaelG,

I understand how you would like to see the full hyperlink displayed however, due to the limitations of this forum software, long hyperlinks often 'mess up' the formatting of the site, which is why the advice is given to effectively hide the full link behind a text anchor. Failing this you can also utilise tinyurl links, all of which are a safe way to embed hyperlinks within a post.

The software behind this forum is less than optimal but I doubt the publishers are ever going to listen to us, we have been complaining about it since its inception!!!

So we are stuck with 'workarounds'

I limit my postings on this forum for that very reason!!!

regards

CB

[Gone AwayParticipant @goneaway]

Posted by Michael Gilligan on 04/04/2012 15:57:13:

Somewhat reluctantly however; as I generally prefer to see hyperlinks disclosed in full, for the sake of security.

Just hover your mouse pointer over the link and your browser should show you the actual link.

Tinyurls don't do this (or at least don't show you the final destination) and are the least secure since you have no idea where you are being ultimately redirected. It's not uncommon for them to be used maliciously. Personally I never click on them unless I'm very sure of the source

[Michael GilliganParticipant @michaelgilligan61133]

CB and Sid,

Thanks for the helpful comments.

It's not your problem, Sid; but I will just mention that the iPad [which I prefer to use for browsing] does not do hovering … an inevitable consequence of the touch screen.

MichaelG.

[Gone AwayParticipant @goneaway]

Yes, I see the problem, Michael. You can do it (sort of) on the iPad by holding your finger on the link until you get the pop-up, selecting <Copy> and then pasting into something (such as the "Notes" app). Not very convenient though admittedly.

Might be worth Googling around to see if there's a better way. There's all kinds of tricks that I stumble across for the iPad – especially if you have twelve fingers

Then again, a malicious link is unlikely to be targeted at an iPad or its apps/OS.

[Michael GilliganParticipant @michaelgilligan61133]

Sid,

Thanks for the thoughts … although what you suggest does rather spoil the "feel" of interacting with the device.

Whilst it is most unlikely that any malicious code would be introduced into the iOS, there is a distinct possibility of one being redirected to a site that one would rather not visit. [Paranoid … Moi ?]

My ultimate safety check would be to look at the source code for the page [*] … but that really does ruin the intuitive experience!

MichaelG.

[*] using this clumsily named, but extremely clever, App

HTML5, CSS, JavaScript Snippet Editor

Please Note: I have no connection with Angel Software Studio

[ian weeks 1Participant @ianweeks1]

Dear All ,

Just a quick note to say thank you for your advice and a special thanks to michael and Martin for the Excel advice and program. Hope to get time to play with these this weekend. As an aside ,having taken a little trouble with the table I am pleasantly surprised and I wont be as quick ,rash or cocky in future in dismissing the quality of these Indian products .I may just have been given a surprisingly well made one but having played the other night and randomly spotted holes in some scrap .and then transfered the 'scrap' to my Theil dividing head and re spotted the holes to compare– they were [sorry] spot on!!

just have to make or badge some 'fingers for it now as these were missing when I was given it.

Kind regards and thanks again Ian

[Author]

Posts