Sunday, October 23, 2011

Making A Third Hand Jig

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.

10221101
Some 3/8” steel chucked in the lathe.

10221102
Groove cut.

10221103
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.

10221104
The finish is pretty good.

10221105
One down…

10221106
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.

10221107
Dressing the stem a bit.

10221108
Drilling a hold for a push fit on the shank of an alligator clip.

10221109
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.

10221110
Setting up the vise so a hole is drilled on center. The ruler trick works well.

10221111
Drilling…

10221112
Three pieces with 1/4” holes.

10221113
Drilling for a #8 tapped hole.

10221114
Three pieces done.

10221115
Drilled and reamed a 5/8” piece of steel rod for the shank of one of the ball pieces.

10221116
Drilled for a #8 screw.

10221117
Another part done.

10221118
Drilling three pairs of steel plates. Two holes for the balls and one for the #8 screw (one piece clearance, the other tapped.)

10221119
Tapping.

10221120
Almost done, sort of.

10221121
Matched pairs screwed together.

10221122
Ends radiused for clearance and aesthetics.

10221123
Drilling some brass rod for a press fit on the heads of the #8 SHCS.

10221124
Knurling.

10221125
Cutoff.

10221126
Knurled heads pressed on the screws. Note that I sanded and polished the parts.

10221127
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…

6 comments:

John Bear Ross said...

Very nice. What are you going to do with the $7 you saved? ;)

Best,
JBR

Nick Carter said...

It goes towards the $600 I just spent on a used makerbot...although my accountant says that's not how finance works.

spokehedz said...

You should put some hemostats on there, instead of those weak clips. They lock, and I much prefer that to the weak clips.

Nick Carter said...

Yup, that's the next project, putting better grippers in place.

Anonymous said...

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.

Nick Carter said...

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.