A Tale of Jam Chucks and Sunbursts

[nuhobby]

Recently I'd posted a new segmented (coffee) Travel Mug in the Santa's Projects thread here. This new pretty one was for the better half, to replace a 4-yr-old one that was delaminating and quite stained at the open joints. It's shown in the picture here sitting on top of the headstock.

All along I knew the delamination of the old one was because I never jointed the glue-up pieces well in the first place. I remember stupidly clamping it "real tight" during glue-up to keep it from "sproinging apart" where there were gaps due to a bowed piece.

Ahh heck -- being too sentimental to throw out the old one, I was recently perked-up by terrydownings's (yes, I pronounced that like Gollum does) recent mention of Jam Chucks. Next thing you know, I'd made a jam-chuck to go in the metal sleeve of the old mug. Got it sanded down and inserted some thin veneers into the open joints. That was a big improvement but there were still deep stains near the bottom. Then I remembered the "sunburst effect" done on some guitar finishes, where a heavy stain blends into a no-stained area. So I've started adding that effect with a black magic-marker. Hey, this is kind of addictive; I don't think I'm going to throw away that old mug....

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[terrydowning]

Really nice!!

Glad something I mentioned helped someone out! This is a great example of a Jam chuck.

And a good save too! I need to find one of those kits as my current stainless mug with 10 yrs of service is dented and barely stands on its own anymore.

[nuhobby]

I had occasion to need a little jam-chuck today. I was making a custom wood knob where I wanted a 7/16" dowel-mount as well as a concave face. Hard to do all that with a single mount.

I started with a rough knob-profile and a 7/16" hole drilled with a tailstock bit. Then I parted-off:
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Next I drilled for a 7/16" short dowel in my waste faceplate wood. This became my jam-chuck:
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The jam chuck was tight enough to do my concave cutting on the knob-face, but just loose enough where I could rotate the rough knob to a position that minimized the rotational run-outs. Then I was all set to cut, sand, and polish!
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