Tool Tuesday 7/7/2015

Tap and Die Kits

If you like to fabricate your own cases and enclosures or you need to fix a stripped out nut or bolt these two types of tools are a life saver. They are used to create threads. Taps are used for cutting threads into nuts or whatever needs to hold a bolt. A Die is used to cut threads into bolts. When using these tools you need cutting oil so you don’t ruin your Tap and Die. WD-40 and 3-in-1 oil works great most of the time but for hard metals you need Kerosene or mineral spirits mixed with a small amount (10–15 percent) of petroleum-based cutting oil. For plastic and Wood you do not need any cutting oil. Once again you get what you pay for but if you are like me then a couple of cheap sets are fine. I myself have two metric sets and a few loose standard types. If you store them out in the elements of a shed then you want to keep them oiled or rust will develop on them. Try and get a set made from Carbide, yes they are pricey.

I attend to use metric machine screws so I use both metric sets often. The only issues I run into is cleaning out the tapped holes when using the cutting oil since I don’t have my compressor anymore. The real trick to using these is staying straight because the first couple of turns is what counts because if you end up in a angle you really can’t start over.

Threaded insert

Here lets talk about threaded inserts. One name brand most machines know is called heli-coil but there are several types. When you’re building say a case out of plastic for a project you want to try and avoid using self tapping screws. There are types you just drill then press to fit the insert. Some you drill a pilot hole and screw in the insert that has some sort of massive thread design. Some would have to molded into the plastic. I myself prefer the press to fit insert. You can use a adhesive like wood glue, J-B weld and so forth. For metal I like the old heli-coil. These are used to repair or change thread size of a bolt hole. You drill out the old placement hole, tap it then add the heli-coil with some thread glue like loctite. This way if you have a oil pan on your car using M6-1.25 bolts to hold it on and one bolt hole is stripped out because the engine block is a soft aluminum and instead of tapping a M8-1.25 as it’s replacement you can use a heli-coil that will keep it the same M6-1.25 threading.

In the past I have used heli-coil on wood and plastic. Works well if you use the right adhesive. In a pinch I have used a self tapping insert by heating it up and screwing it into plastic.

Next week I’ll rant about wire strippers and crimppers.

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