Sunday, August 22, 2010

Shed tips - free shim steel, and parallels

just another post to prove I'm alive, and trying to live up to my commitment to publish up the things I find useful, hoping someone else finds them useful.

Another "free" tip - shim steel
The anti-theft widgets I find inside PC software, DVDs and other packages often looks like a small rectangle. Inside is normally 3 pieces of incredibly thin steel - suitable for shimming tool bits up to 1/4" wide.
After several years of cutting these things open, only to fight with the sticky tape inside, this is the easiest way I've found to open the widget.

Figure 1 - the "unopened" widget

Using a sharp knife, slice the case near the bottom flange

Figure 2 - opening the widget

Remove the strips which you can easily - there may be one at the bottom under another layer of sticky tape - leave it at this stage

Figure 3 - the removed pieces, and one still in the case (under tape)

Cut the end off the rectangular plastic, as close to the end as possible

Figure 4 - sliced tape so the last piece can be retrieved

Insert the point of the blade between  the tape and the shim, and then slice back into the tape to cut the top off for at least 1/4".
Remove the remaining shim, discard the rubbish.

Result - Three pieces of shim, without any glue residue, or creases.

Bonus Tip  - "free" parallels
 an oldie but a goodie
Salvaged bearing races make good parallels, particularly for packing on the mill or lathe.
I took the time to dismantle a stash of saved bearings which were not worth saving (sand in the races)
Someone suggested drilling out the rivets holding the cage together - easier said than done, and it cost me a 4mm HSS drill - not again.

Figure 5 - old bearings too rough for use - destined to be dismantled

What I did was use on of my punches to drive the cage towards one side (punched in the gap between 2 balls) so the cage was deformed to the other side, then flipped the bearing and struck it back - I repeated this about 2 times and the cage broke at the point of the flexing. Using the point of the punch, I levered the cage material up, and then started winding it around the points of some pliers - most of the time the metal tore at the rivets, sometimes it broke, and all I'd do is commence from the other side and eventually all the cage was removed.
Then it was simply a case of pushing the balls all to one point in the races, and the inner race was able to be persuaded into the side without balls to drop away freely.

Figure 6 - a collection of free parallels for packing on the lathe.

Each bearing yielded 2 races with perfectly parallel sides, and a number of ball bearings which get filed away for use in detents, etc.

Speaking of detents - I pick up old disposable cigarette lighters whenever I'm out walking the dog - people are forever dropping them on the streets when they run out, or become damaged, The mainspring (the one pushing the flint up) is the perfect size for making/ replacing small detent springs (and extractor springs for rimfire bolts) - just another excuse to bring home junk, then pull it apart and file the parts.

What's on the horizon?
Webpage wise - I'll push to continue reviewing and recommending books - I can do that with little to no shed time.
Shed wise - Added 2 more projects to the "To Do" list (the "do to" list is at 12 major projects, and 23 minor projects and counting) - first is a couple of MOT spot welders (wound the first transformer last weekend), the second is building a electronics device to semi automate gear cutting... there are commercial offerings out there which do this, but the ulterior motive in this is getting my microprocessing skills back - I'm an Electrical/ Electronics engineer by training, but I spend more of my leisure time doing mechanical fitting - the irony has not escaped many people, especially myself.

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