GearHeads Corner

Well, I wasn't sure where to put this, but I figured someone here might know and this category seemed broadly appropriate...

...does anyone know where I might find a set of plans/diagrammatic drawings for an old (1800s) topping tool (also a "rounding up tool")? I've been digging for patents etc., but haven't had much luck yet, and the tools themselves haven't been in wide use for quite a long time.

I'm referring to this sort of thing:
http://goldmachinery.com/?s=rounding+up+tool

I'm sorta considering building one purely for the hell of it, but cannot afford to just buy one and copy it.

Hi:

  Interesting tool, I hadnt seen one before. A kind of desktop hobbing
machine of sorts. I suppose they call it a topping tool as they use it
to get the cycloidic leaf tops from a gear made of squared teeth?

  Interesting machine. Please let me know how it looks if you start
building one. Looks like quite a neat project if you have the shop
for it.

Art

Yep, they seem to have been used for situations (watchmaking, not clock making) where it was easier to run a slitting saw around a circle, and then load the result into the topping/rounding tool to get the final tooth form. They mainly seem to use what are often called Carpano cutters (although there may have been more than one manufacturer of said cutters); these were fairly interesting little widgets -- basically disks, with one little section being cut nearly loose, bent up out of the plane of the disk, hardened, and then fitted with a little screw.

The screw, when tightened, tries to force the "sprung" section back down into the plane of the disk. Thus, by adjusting the screw, you can finely control the width of your cut while still using just one basic cutter for each "module" (they used their own numbering scheme described here: http://www.vintagewatchmarket.com/horol ... tters.html ).

I still only barely understand these things, but they're kinda nifty.

Thanks for the info Mand,  however I'm unable to connect to link..  http://goldmachinery.com/?s=rounding+up+tool 

Anyhow, Until a few days ago, I was oblivious to how this tool really worked, so thanks for sharing.


Cheers
Bob
:D

Weird, are you using Chrome? The link goes to a machinery reseller on the East Coast, and they don't use HTTPS, so some installations of Chrome may stop you from going there (I mean, if it's been set to avoid non-HTTPS sites as being a security risk).

Alternatively, then, there are several listed on eBay at the moment (some for staggering sums); if you search for "rounding up tool" you'll find most of them (folks seem to list these using varying phrases, some wrong, so they can occasionally be found hiding under other search terms. I've seen at least one described as being a lathe, for example.)