Scroll plate and Jaws design for self centering chuck

[cka3ka2]

I'm trying to design a small 3 jaw chuck, but I'm stuck, because I don't know how to make "teeth/grooves" in jaws so they can match spiral on the scroll plate. I designed scroll plate using spiral function in Fusion, then positioned all 3 jaws in the center and used combine option to cut out grooves in them, but I don't think this was right approach because as jaws move diameter of the spiral changes so teeth get stuck. I'm stuck and jaws are stuck 🙂 Please help me 🙂

[jhackney1972]

Please attach your model, I would like to take a look.  If you do not know how to attach your Fusion 360 model follow these easy steps. Open the model in Fusion 360, select the File menu, then Export and save as a F3D or F3Z file to your hard drive. Then use the Attachments section, of a forum post, to attach it.

[cka3ka2]

Hi John. Thank you, here's the model attached.

[etfrench]

The flanks of the teeth on reversible jaws are not parallel or the same radius as the scroll.  They are also offset from the centerline of the jaw.

Unfortunately, I don't have a three jaw chuck with single direction jaws.

It's probably more accurate to say the scroll is not aligned with the centerline of the jaw😁

It's easy to see when the jaw is just being engaged by the scroll.

[etfrench · Accepted solution]

The inner face of each tooth on the jaw needs to match the maximum outside circumference of scroll.  The outer face needs to match the minimum inner circumference.  You'll also need to a little clearance.  Each tooth needs to be the same shape.

[cka3ka2]

Wow thank you so much! I think I understand now. I will try to redesign it tomorrow. I really appreciate it, thank you everyone who replied!

[cka3ka2]

One more question. How would you model the other 2 jaws? They usually have different groove pattern due to the order of insertion into the chuck...

[etfrench]

The pattern of the teeth on all of the jaws is the same, just shifted in or out to match their location on the scroll.  I would create a tooth pattern component, then adjust its position on the jaw component.  There are multiple ways this could be done.

p.s.  The outer ring of the scroll should pass through the same gap in the teeth on each jaw when the tips of the jaws are the same distance from the center.