Decision support on an indexing rotary capability

extropic said:
Clock work,
Your detail photography is great but you're not displaying the "big picture". Please show "overview" photos, then zoom in.
You mention "a ring with two 5mm grub screws holding the shaft" but I don't see it in any of the photos. Where is it?
WAG = The grub screws have done damage where they bit into the soft shaft and that's why the ring is hard to remove. Keep trying. Can you see shaft damage through one or both of the grub screw holes?
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Absolutely fantastic call on the messed up threads. That was exactly the problem. Sincerely appreciated.

My epic choke (today) was not realizing that once I got that bunged up ring off the shaft and could extract the worm "carrier" that the ball thrust bearing would itself then literally leap out with the worm. So glad I read all those engineering books.... I need to drive over to the brain institute and get another dose of the "magic peanut butter", if you know what I mean.

Photos of the work post reading your suggestion:

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Leverage setup to drag the ring free

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Success shot, like the group photo at the end of Wonder Woman:

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The result of having a grub impinge directly on a thread shown. I guess they grant tenure in off-shore machine shops. It's 24tpi but just a shade under 17mm. I obviously need to go check something but I trust the 24... the gauge just dropped in perfectly. Shaft.. messed up. Ring... it'll survive. I'll go out on a limb and say I don't have a die for that particular shaft thread... any further thoughts? Triangular jeweler's file maybe?

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So here's the grease. I looked closely at the the locations/paths of the ball oilers and conclude there are oil areas fed by the oilers, and 3 grease areas:

1 & 2: The big bearings supporting the plate in the casting... i.e. front and rear. And..
3: The worm.

The oil ports just don't talk to these places. So grease it shall be there. Anyone recognize or care to take a shot at that yellow stuff on... everything? Sorta like bringing a consultant into the room with the mainframe and asking him what he thought the software error was by just looking at it from the doorway. Of course, back when there were real computers (11/70 and the Seaview) you actually could tell from across the room. I digress... I'll put oil on the rest when I assemble and test it and report back how it performs.

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Charly Gordon
 
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Yes, use a triangular (proper name = tri square) jewelers file to cleanup those threads. Be sure to clean everything so no filings get into the lubricants.

Reassemble with a short slug of brass (or an actual 5mm brass screw cutoff) under each setscrew. The 17mm thread form will bite into the brass and prevent it from turning and the setscrew will do it's job without damaging the 17mm thread.

I don't worry too much about having "the perfect" lubricant for these types of light duty applications. I would probably use (have used) white Lubriplate. Maybe someone else has a specific recommendation.
 
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extropic said:
Yes, use a triangular (proper name = tri square) jewelers file to cleanup those threads. Be sure to clean everything so no filings get into the lubricants.

Reassemble with a short slug of brass (or an actual 5mm brass screw cutoff) under each setscrew. The 17mm thread form will bite into the brass and prevent it from turning and the setscrew will do it's job without damaging the 17mm thread.

I don't worry too much about having "the perfect" lubricant for these types of light duty applications. I would probably use (have used) white Lubriplate. Maybe someone else has a specific recommendation.
Click to expand...

Thank you and sincerely appreciate the correct terminology. I know my grease usage on motorcycles, boats and tractors but just seizing the opportunity to learn in the new-to-me domain of shop machinery. I'd loved to know what that yellow stuff is... very thick... not hardening or skinning over like cosmoline... the manual doesn't have a peep about lubrication though averaging out the recommendations of manuals for other tables makes the "what" of selection simple but less the "why". I also notice that the oiled/sliding surfaces show a black graphite like content.. perhaps a moly grease. As an FYI if anyone knows of a good one, I'm looking for a good book, preferably 30's thru 50's, for machine design with hopeful a discussion of lubrication. Thanks again.

CW
 
kd4gij said:
You can get soft tip set screws that won't mar those threads.
https://www.mcmaster.com/#set-screws/=1d47x4a
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The problem with using a soft tipped setscrew bearing on threads is that turning the setscrew causes the soft tip to be scarfed away by the peaks of the thread. Using a separate piece of brass, between the setscrew and shaft, it becomes non-rotating as the setscrew is tightened for the first time.
 
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The brass tipped setscrews that I have used the tip would rotate in the screw
 
kd4gij said:
The brass tipped setscrews that I have used the tip would rotate in the screw
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I've never seen what you describe but they certainly could exist. I've bought various sizes from McMaster and all brass tips have been rigidly attached. I don't know if they're bonded or press fit but I've never noticed any relative rotation. McMaster doesn't mention such a feature in their description.
If I remember, tomorrow I'll sacrifice some samples to see if I can turn the brass with pliers. It could happen.

Now that I'm thinking about the issue a little more, McMaster sells brass balls and dropping a 5/32 brass ball into the hole before installing the M5 grub screw might work a treat. Brass Balls
 
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My absolute final post on this holy grail search:)...

Hours of "research" (that term has been rendered utterly devoid of meaning by the web) has resulted in the discovery of APPARENT special needs of a yellow-metal worm gear... both parts of that have meaning... yellow metal, and worm gear. The open nature and pressures that can be involved appear to suggest a grease is preferable to an oil... stays on better and less frequently disassembly and reapplication. Perhaps a #2 is not far off as far as NLGI ratings go. The yellow metal part suggests to stay away from greases that contain additives hostile to bronze, brass, etc. like some EP additives do. Add this to the suggestion for this particular table cited in the previous entry to use a "multi purpose gear grease" which as best I can tell thru my "research" is mostly a made up term but might be a technical writer encapsulating a concern for yellow metal by saying "gear". So... I can go buy me $500 worth of Lubriplate Gear Grease (ain't going to happen) or just put it back together and let my estate worry about it. The latter not being how I'm wired on most things.

It's INCREDIBLE how a life in ilfe/mission-critical engineering and getting on planes to FORCE rooms full of smart guys to make the best possible technical decisions DESTROYS fun at literally anything after you stop doing that:) Perhaps origami or bird houses is for me. Ok.. no more shall be typed in about rotary tables by me. Enjoy:)

CW
 
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