Intro: Holder for a Glass Fuse
This is a free multimeter I got at Harbor Freight with a coupon. It came as a surprise, but there is a fuse inside.
See the second photo. Details about the fuse are included on the back of the meter's case, but it is easy to miss them. See the yellow arrow. The fuse is 0.5A at 250 volts. The size is 5mm x 20mm.
See the third photo. This is the fuse in the factory supplied holders.
See the fourth photo. The factory fuse holders are more flimsy than any I have ever before seen. When the fuse is removed, the holders move. The holder on the right feels especially loose and marginal. If they were made of heavier material, I would simply resolder them. But, I want to replace them. (I could just solder the fuse to leads, but I want replacement of a blown fuse not to require a soldering iron.)
Step 1: First Steps
See the second photo. Ream away rough edges and clean the inside of the brass tube with a round file.
- Tubing cutter
- Round file
- Soldering iron and solder
- Small scissors
- Pair of pliers
- Heat source (hair dryer, match, etc.)
- 9/32 O.D. brass tubing
- Heat shrink tubing
Step 2: Fitting the Tubing
I found I needed to remove nearly one-fourth of the circumference of the brass tubing so it could fit snugly around the end cap on the glass fuse. I used a small stainless steel scissors.
See the second photo. I used a pair of pliers to make the tubing fit the fuse. It was still a little loose, so I crimped the tubing just a little without the fuse to get a closer fit. Caution: These little glass fuses are delicate. I broke one by pushing too hard on it.
Step 3: Solder Leads
When the fitted brass tube sections fit the fuse end caps nicely, tin each with solder and solder a short piece of insulated wire to each for a connecting lead. Cut two short pieces of heat shrink tubing and heat to shrink.
I had hoped the heat shrink tubing would add the right amount of tension to the brass tubing, but that proved an invalid hope. Before I tried the brass tubing, I thought about using some thinner sheet brass I would bend around the end caps. It is flexible enough that the heat shrink tubing probably would have made the brass fit snugly around the end caps. Because the heat shrink tubing did not add tension, I tweaked the fit by crimping just a little with a pair of pliers.
Step 4: Solder Leads in Place
Solder the leads on your improvised fuse holder in place. Check with a continuity tester on another meter to be certain there is an electrical path through the brass tube and end cap junctions. The heat shrink tubing also insulates the metal parts of the fuse so they do not short anything on the circuit board. I also bent the connecting leads a little so the fuse and its holders are suspended above the circuit board.
See the second photo. This shows that the improvised fuse holders can be removed easily when it is time to change a fuse. I should get an extra fuse or two, cover them with tape to keep them for shorting anything on the circuit board, and store them inside the case of the meter.
This Instructable may fix something that was not completely broken, yet. But, I just did not like the very flimsy factory fuseholders. A fuse holder like this could be used anyplace a fuse is needed.