This is a great lesson in why it is often easier and cheaper to buy something than make it. You can get a 3rd Hand Jig for under $7.00 which functions reasonably well and even has a magnifying glass. But as with many things that is too easy a route to take.
Some 3/8” steel chucked in the lathe.
Groove cut.
A Shaplane radius tool is used to turn a ball end. Setup takes a while but once done it’s easy to get relatively uniform results.
The finish is pretty good.
One down…
I needed 6 but I cut seven, just in case. Notice there’s a bit of variation in the turned down shanks. As you can see by the precision CAD drawing I’m not that worried about tolerances. The goal was to make a functional third hand tool as rapidly as possible.
Dressing the stem a bit.
Drilling a hold for a push fit on the shank of an alligator clip.
The alligator clip ends are a bit springy so they will stay put in the hole. Later I may make a better tweezer to replace them.
Setting up the vise so a hole is drilled on center. The ruler trick works well.
Drilling…
Three pieces with 1/4” holes.
Drilling for a #8 tapped hole.
Three pieces done.
Drilled and reamed a 5/8” piece of steel rod for the shank of one of the ball pieces.
Drilled for a #8 screw.
Another part done.
Drilling three pairs of steel plates. Two holes for the balls and one for the #8 screw (one piece clearance, the other tapped.)
Tapping.
Almost done, sort of.
Matched pairs screwed together.
Ends radiused for clearance and aesthetics.
Drilling some brass rod for a press fit on the heads of the #8 SHCS.
Knurling.
Cutoff.
Knurled heads pressed on the screws. Note that I sanded and polished the parts.
All together. It mounts in one of my Panavise bases. Once tension was set on the screws it holds well in position and adjusts relatively easily. Whole thing took about 4 hours not including the time spent cleaning up the shop afterwards…
Sunday, October 23, 2011
Making A Third Hand Jig
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6 comments:
Very nice. What are you going to do with the $7 you saved? ;)
Best,
JBR
It goes towards the $600 I just spent on a used makerbot...although my accountant says that's not how finance works.
You should put some hemostats on there, instead of those weak clips. They lock, and I much prefer that to the weak clips.
Yup, that's the next project, putting better grippers in place.
I would like to know your thoughts on the SHAPLANE Radius Tool, I have a 10K myself and would like to get a ball turner. What model are you using? I was looking at the model that does the 1 5/8 inch ball-item# A1-248-05.
Thanks for you time.
I have the smallest one, the 1-5/8" ball. It works ok but setting the toolbit is a bit tricky - you have to measure between the back of the toolholder and the tool tip. It would be easier to use in a lantern toolpost rather than a quick change toolpost. I think the Holdridge ones are superior and there are other options such as making an "up-and-over" style or getting one of the inexpensive OMW ones.
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