OMB Dividing Head Help

Charts for 40:1 dividing heads are published in the Machinery's handbook and likely any other machinist's handbook; so far as I have seen, only rotary tables are made in 90:1 ratio.
 
pontiac428 said:
Looks like a winner! I probably would have it pulled apart by now to clean the internals and familiarize myself with its functions.
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I’m a bit of a bull in a China shop, my first thoughts are always tear it down and see how it works however, my reading suggests that the better quality ones have taper bearings that need pre loads etc are necessary. Taper bearing preload setting is all voodoo stuff to me so I’d rather get a manual with hopefully a schematic and maintenance details before Stepping forward with spanner’s in hand
 
Hi Brino
It’s definitely 40:1ive done a wind around. I’m wasn’t the guilty party who wrote the 40 on it.......Neanderthal who ever they were
 
benmychree said:
The end gearing is for differential indexing so that prime numbers can be indexed, and also so that spirals may be cut. If this is a 40:1 ratio unit, info pertaining to any other universal dividing head of the same ratio would be appropriate.
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Thanks, that’s sounds really interesting. Any pointers to info on using the end gear to index primary numbers?
 
A nice bit of kit!

Info on differential dividing here:


I've yet to see a complete set of charts and have developed a pc app that calculates both indexing plate and differential dividing solutions based on what plates and gears you've actually got. I gave up with tables. Happy to send a copy over, be great to get some feedback.
 
Wow, Lo-Fi, that’s a brilliant link. Is that your video? Super informative.
Typical though my lathe has a gear cutting box so I don’t have any gears to make up a train. I can see exactly how it’s extremely useful as the plate size on indexing head is fairly small preventing I believe the development of high hole counts leaving gaps on what could be indexed.
I’d love a copy of your spreadsheet, thank you it’s appreciated. I’m fairly new to forums, so not sure how you‘d send stuff to other members. If I need to do something please just let me know.
 
Not my video, but one I used extensively when researching how to get the best out of my dividing head. Don't worry about lack of gears: mine only came with a single gear. I cut the rest myself!

The other cool feature of the aux input on a dividing head is the ability to gear it to the table feed and spiral mill, cut helicals, make cams... All sorts of interesting stuff.
 
Deema said:
I’m a bit of a bull in a China shop, my first thoughts are always tear it down and see how it works however, my reading suggests that the better quality ones have taper bearings that need pre loads etc are necessary. Taper bearing preload setting is all voodoo stuff to me so I’d rather get a manual with hopefully a schematic and maintenance details before Stepping forward with spanner’s in hand
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I say, "let sleeping dogs lie", a lot of damage can be done by the well intensioned in disassembling the innards of a sophisticated mechanism.
 
Lo-Fi said:
Not my video, but one I used extensively when researching how to get the best out of my dividing head. Don't worry about lack of gears: mine only came with a single gear. I cut the rest myself!

The other cool feature of the aux input on a dividing head is the ability to gear it to the table feed and spiral mill, cut helicals, make cams... All sorts of interesting stuff.
Click to expand...
Find a copy of Brown & Sharpe's book, "Practical Treatise of Milling and Milling Machines", it presents all phases of the milling processes in a clear simple manner, right down to the calculations for dividing, both simple and for prime numbers, spiral milling, and is complete with tables of dividing and tables of leads for spiral milling. All the info. pertains to the dividing head that you have (40:1 ratio). Cincinnati Milling Machine Co. also published a similar book, but much more wordy and technical.
 
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