Holding irregular parts with an old gear

Wild hair ... inspired by the round shaft that @Winegrower has in his photo ... cut a "lengthwise" vee in one of the gear segments, so it will more securely clamp onto round parts. If the part being held has a flattish surface, you can put the vee'd segment against the vise jaw.
 
Aaaahh K, twisted my arm: here's what I'll call Downtown Clamping, Home Shop Address.
We've directed attention to one remedy, a semicircular adjuster compensates misalignment of shaped parts between parallel jaws.

This is not my creation, but one sample of others I've made.
Secure clamping relies on directing pressure quite figuratively 'through' the part to an opposing fixed surface; as in moving and fixed jaws of a vise. And whether vise, clamp, or hold down; they like parallel surfaces best. But that's just not always 100% feasible.

Just as a C-clamp needs a swivel pad to correct out-of-plane surfaces, this can take serious pressure, using a swivel action, for tapers, radii, curves and compound surfaces, as in cast or forged parts. Self adjusting, it uses less space, very advantageous when a vise is used.

This is a lathe or mill project, or combination of the two. A little planning will allow making two at a time. Test fits while work proceeds. Heat treating is not needed, or recommended; any steel will do. Only 'requirement' [grossly over-stated], a decent surface finish on swivel area mating to block.

Physical size isn't critical, use steel and adjust to suit material available. Procure two bearing balls, example uses .75/ 19mm. This block is about 2 1/2" long, 1 5/16" high, and 1" deep. The radius inside block [not through] and chord is 1". Allow .002-.004 clearance on one side.
The chord has two pockets bored to slip fit the bearing balls. Ball end milling can be used, but isn't required. If pocket is ball-milled, pilot drill around 1/4 ball diameter and somewhat beyond 1/2 the ball diameter. Seat depth is .020-.030 deeper than 1/2 the ball diameter; for staking. Before assembly, grind flats with any manner at your disposal, nice if close to same height. Lightly stake the balls in place to be retained, not locked. Top edge of chord is grooved for a roll pin pressed into the top plate. In the groove are 2 roll pins at 45° keeps chord from swiveling out of the block.
Top plate is countersunk for 2 #10 flat head screws, tapped in block.
This works in vises, hold-downs and a variety of fixturing.
Uni_Jaw.jpg
If amplification is needed, feel free to post or email questions.
 
@Toolmaker51 - Wowsers! That double swivel action should do a great job on just about anything. I'm impressed!
 
Lightly stake the balls in place to be retained, not locked.

7milesup said:
What does that mean?
Click to expand...

Hole diameter just larger than ball, and deeper than half diameter. Rim of hole is prick punched, so the deformed material retains the ball section. Staking could also be a ring around same rim, formed by a hard version of an arch punch.
 
re "Thinking Out Of The Box";
A friend of extraordinary skill and knowledge elevates that oft-used statement thus.
Thinking out of the box is good, yet a box has finite coordinates, or points of reference. Instead, "Think Out Of The Sphere" as that employs Infinite coordinates.
 
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