01-03-2014, 12:47 PM
So, after some pondering, experimenting and Domestic interuptions - more later - I came up with a plan.
I decided to have a fixed end and a removable end. Two removable ends would probably have been more convenient, but a lot more work.
This is the final Drawing:-
Fixed Ends first - just a bit of Brass Turning really. I knurled the Section that goes into the Plastic to give it some grip, and added a dab of Glue to be sure.
The Free Ends were a bit more tricky but not too bad. The next sensible size up for Tapping was 7/16" UNF, the Tap Drill for which is 25/64". When I fished the Drill out of my Box it proved to be 3/8". Ah, well, get one on order - it's not the sort of thing that the local places keep.
Drilling and Tapping was straighforward, and I'd salvaged a couple of old Biro Springs, so it was just a matter of loading them up with Cells and Testing.
Actually, no. While the Cells are a nice snug fit in a 3/8" Hole they fell in to the Tapped hole and landed any way up. I tried all sorts of angles and methods but to no avail. I only lost 4 while trying
In the end a made a Loading Tube with a 3/8" Hole out of a bit of Nylon, plus a short bit of Streel to push with.
It worked fine - just load the Cells into the Tube where they're a snug fit then push the Cells Vertically into the battery. I could then turn it over and screw in the Free End using the two little indentations in the end and a pair of small pointy Pliers.
Fitted to the Protimeter they work fine, and the Loading Tube and Pusher sit nicely in the space where the original Battery would have fitted.
As far as I can tell the House is pretty Dry so that's a relief.
Would I do it the same way again? Possibley not, although it would depend on how many I was making.
Am I taking Commissions? No.
Should I paint them Red? Don't know.
Alan
I decided to have a fixed end and a removable end. Two removable ends would probably have been more convenient, but a lot more work.
This is the final Drawing:-
Fixed Ends first - just a bit of Brass Turning really. I knurled the Section that goes into the Plastic to give it some grip, and added a dab of Glue to be sure.
The Free Ends were a bit more tricky but not too bad. The next sensible size up for Tapping was 7/16" UNF, the Tap Drill for which is 25/64". When I fished the Drill out of my Box it proved to be 3/8". Ah, well, get one on order - it's not the sort of thing that the local places keep.
Drilling and Tapping was straighforward, and I'd salvaged a couple of old Biro Springs, so it was just a matter of loading them up with Cells and Testing.
Actually, no. While the Cells are a nice snug fit in a 3/8" Hole they fell in to the Tapped hole and landed any way up. I tried all sorts of angles and methods but to no avail. I only lost 4 while trying
In the end a made a Loading Tube with a 3/8" Hole out of a bit of Nylon, plus a short bit of Streel to push with.
It worked fine - just load the Cells into the Tube where they're a snug fit then push the Cells Vertically into the battery. I could then turn it over and screw in the Free End using the two little indentations in the end and a pair of small pointy Pliers.
Fitted to the Protimeter they work fine, and the Loading Tube and Pusher sit nicely in the space where the original Battery would have fitted.
As far as I can tell the House is pretty Dry so that's a relief.
Would I do it the same way again? Possibley not, although it would depend on how many I was making.
Am I taking Commissions? No.
Should I paint them Red? Don't know.
Alan
