Lathe Toolpost Stud Thread

[Techo1]

If you look at commercial fastener threads under magnification ie. profile projector you will see that the thread forms are not exactly 55 or 60 degrees and generally not even a true Vee with flanks poorly formed by the rolling process.

[nadroj]

I think metric is far superior, not only for being based on a nice measurement system that is easy to use and transfer from one field of work to another, but because it is sticks to the one number format and is readily scaleable.

There must be something in the imperial system. Italy uses British Standard Pipe thread for water supply valves etc.
Could it be that common metric threads aren't coarse enough?

Jordan

[scottyd]

Right you are pipeclay, I thought there was others, but my memory was incorrect. 1/2in a very common size though, making the two standards differ by threadcount is a big call.

[electrosteam]

The saga continues.

The QCTP brass insert was pressed out and and the precision bore in the body confirmed at Dia 18.
Interestingly, the insert was a relatively loose fit into the precision bore and tight in the body.
A new stepped bush was made to match the Dia 18, and the Dia 30 recess in the Topslide.

Before installing the new arrangement, with a 3 mm aluminium packer plate, the QCTP was disassembled and cleaned.
The photo shows that one of the cam operated drawblocks showed significant cracking.
The Algra agents, Modern Tools (Vic), were contacted and two new drawblocks purchased.

The installation is now considered complete.
The photo shows the brass insert and the cracked drawblock.

Algra Brass Insert Cracked Drawblock 20131124.jpg

I will add a yearly QCTP strip/inspect/clean check to the maintenance schedule.
John.