Brian, in this example we'd obviously only have a 25% overlap. Our aim is to get the amount of overlap as high as possible but still allow us to thread them without cracking. Like I said, the '5' was too cautious and I should have used a slightly smaller hole.
The 'feel' would be fine, as the depth of the cut is what determines the 'snug-ness' of the mating parts.
If we only used a taper tap and an un-adjusted split die ( or one of those solid ones) then we wouldn't have any control over the depth of the cut, irrespective of how big the hole was and what diameter we turned the male piece.
The male and female parts in this topic are actually very tight and I would either have to re-tap with a 'second cut' plug tap or squeeze the die and re-do the male part.
If I had bought the taps in a set of three ( 1st, 2nd and 3rd cut ) then in this instance, retapping with would be the best choice. To try and increase the '5'
Ok, I know that the purpose of the set is to progressively extend the threads into a blind hole but as the taper tap ( of a set )does more work than the other two, then hopefully the less worn 2nd or 3rd tap would remove a bit more material as well.
This is where the use of a metal lathe is so good as these cut depths can easily be adjusted.
In a nutshell though, what we want to ensure is that only the triangle ( or preferably just most of it) from the zigzags is removing material. If the turned part is slightly too big or the hole is slightly too small, then we actually use the flat surface of the flute to remove material.
Hope this helps:biggrin:
The 'feel' would be fine, as the depth of the cut is what determines the 'snug-ness' of the mating parts.
If we only used a taper tap and an un-adjusted split die ( or one of those solid ones) then we wouldn't have any control over the depth of the cut, irrespective of how big the hole was and what diameter we turned the male piece.
The male and female parts in this topic are actually very tight and I would either have to re-tap with a 'second cut' plug tap or squeeze the die and re-do the male part.
If I had bought the taps in a set of three ( 1st, 2nd and 3rd cut ) then in this instance, retapping with would be the best choice. To try and increase the '5'
Ok, I know that the purpose of the set is to progressively extend the threads into a blind hole but as the taper tap ( of a set )does more work than the other two, then hopefully the less worn 2nd or 3rd tap would remove a bit more material as well.
This is where the use of a metal lathe is so good as these cut depths can easily be adjusted.
In a nutshell though, what we want to ensure is that only the triangle ( or preferably just most of it) from the zigzags is removing material. If the turned part is slightly too big or the hole is slightly too small, then we actually use the flat surface of the flute to remove material.
Hope this helps:biggrin:
