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> Tapping block, plated heattreated 4140 steel won't rust
Tapping block, plated heattreated 4140 steel won't rust
Starting straight is the most critical part of tapping a hole-an off-angle start can not only be hard to correct, but also cause the tap to jam and make it more likely to break. This simple block has close fitting holes that easily guide a tap straight into a hole (#0-3/8").
Why is this better than a cheaper aluminum tapping block? This block is made of tough, heat treated 4140 steel, and it's plated with an even tougher layer that will keep it from getting dinged up in a shop. More wear resistant than chrome, the plating also permanently prevents rust so you don't have to worry about keeping a protective layer of oil on it.
To use, first apply tapping fluid, then turn the tap about two revolutions while holding the tapping block flush against the part surface. After this, repeatedly reverse the tap until you feel the chips break (about 1/2 turn), and then go forwards again about a quarter turn farther. Depending on the tap, material and cutting fluid, you may not need to reverse at all. Just be sure not to push too hard if you feel a sudden build up of resistance. Taps are very brittle, and once broken off inside your work, they are oftentimes impossible to remove.
How can this tapping block accommodate so many tap sizes with only 7 holes? Taps sized #0-#6 actually all have the same shank size (see the picture below of a 4-40 and 6-40 shank), so the smallest hole works on the entire #0-#6 range.
Won't the tap wrench get stopped by the top of the tapping block before the hole is deep enough? As the following picture shows, the 4-40 tap sticks out plenty far enough. In any case, taps beyond two diameters deep will have threads that are (in most cases) stronger than the screw body itself. But if you do need to tap deeper, you can always start the tap with the block, back out the tap, and then continue on knowing the tap started straight.
All tapping blocks have been checked for squareness.
Made in the USA (designed, machined, heat-treated and plated in Georgia)
* Please email us if you'd like over-night and we'll give you a quote
