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.

Monday, August 9, 2010

Scrounging up materials - tips, etc

I am alive – I’ve just been burning the candle at each end, the middle, and a few other places.  Mostly work demands due to a sudden change in my shifts, but one thing upon another and I haven’t had as much time, or energy, to sit down and update this site.

I did get to do some cleaning in the shed on the weekend just gone, and as part of that I  photographed these two useful tips.

Firstly I need some STRONG steel rod for a couple of upcoming projects. One source of high tensile rod is the rod in a gas strut. I always keep my eyes open for any of these being tossed out, and I opened another 2 on the weekend in front of the camera. NOTE: opening these can be dangerous – I take precautions, but don’t blame me if you get hurt doing this!!!

Figure 1. Gas struts as recovered from being tossed out

The cylinder is filled with pressurized gas and oil. Near the end where the rod comes out there is some crimping which acts like a seal/ travel stop. I dress in appropriate PPE ("Personal Protective Equipment - in this case - ear-muffs, face-shield, leather apron) and work with the grinder and cut area pointed away from me. The first longitudinal cut in that area will suddenly release the gas and oil – I point that in a safe direction and let it vent out. Then once vented, I cut 3 or 4 longitudinal cuts for about 20-30mm above the crimped line. This allows me to remove the rod with it’s piston/ seals captive on the end.

Figure 2. Longitudinal cuts through crimped area to allow piston and seals to be pulled out of cylinder

I then grind off the peened over section of rod, and remove the piston/ seals from the rod.

Figure 3. Showing the peened end of the rod in the piston

The result is a strong, straight length of high tensile steel which has a polished surface. I now have 4 of these rods, one will be used to make the mast/pillar for the magnetic DTI base, another for my upcoming taper turner project, and the other 2 (matched pair) will be set aside as candidates for a Z axis slide in my CNC mill project. The photo below shows the 2 recovered rods on the RHS of the grinder.

Figure 4. Salvaged high tensile steel rods.

A useful tip I picked up from one of the contract firms I saw at a worksite…
We all have had a retractable steel tape measure break on us from time to time, I used to throw them out when I realized I “never get around to fixing them” – Not anymore.

Figure 5. Broken 8m tape measure

Instead I now open them up carefully

Using some heavy duty scissors (good tin-snips will do here as well) I carefully cut the measuring tape into useful pieces

Figure 6. Opened tape measure and snips

Since Oz is a metric country, most tape measures will have meters (with or with out imperial markings on the other side) so I cut the tape on the multiples of 1 meter.

Figure 7. Tape cut on meter markings

The resulting pieces are used as “disposable” yard sticks – useful for taking to messy places, using at the welding table, etc.

Figure 8. Seven 1m "yard sticks" made from one broken tape measure

I keep a stash of them threaded in the frame of the shed door – always there ready for use whenever I need a ruler for measuring something.

Figure 9. About 15 yard sticks threaded in the door frame of the shed.

I have 2 broken tape measures I haven’t cut up yet “in storage” for my CNC mill – these will be affixed on the sides of the axes for quick positioning/ verification under jog/ MPG control.

If I have time, I’ll put up the account of the other salvaged/ scrounged useful junk I worked on during this weekend’s clean up. (free shim steel and “free” parallels)

Time - it always comes back to that - a question of what to do with the limited amount you have each day...