Full profile insert.

[BelgiqueB]

Novice question, when using a full profile thread cutting insert, do you leave the stock slightly oversize and then cut the crest to the correct size using the full profile insert?

If so what is the ratio, how much do you leave the stock oversize and how do you know when you reached the correct cutting depth? For now when I get close I try on the nut repeating this step until the nut goes on smoothly.

Picture tax

 

[Lewis_RX8]

This was given to me by @Kram , Shows the depth of cut and amount of passes you need to do for the pitchs very handy.

 

[Kram]

For stock I aim for dead on or slightly under. Make a note before threading. When you think its done or one pass before, use a needle file to deburr and check same size then use it in the calculation.

Chart was given to me by another member on here, I cant remember who But I have it printed on wall with diameter dial values written on.

The screenshot from the PDF is for internal threads, I cant remember if the PDF had external but its good enough as a guide for external. Neither internal or external are exact.
I dont rely on the chart, much better to measure it. Joe Pie' has good videos on how to do one-wire measuring of threads, and DrAl's website is good for the 3 wire calculator.

CGTK - Three-Wire Screw Measurement

www.cgtk.co.uk

 

[BelgiqueB]

Thanks for the info!

I found the original PDF which has both the chart for internal as for external threading.

http://www.sumitool.com.au/wp-content/uploads/downloads/general-catalog/2015 - 2016 generalcatalogue/068 Threading Tools (SST Series).pdf

Document also answered my question about ho much you need to leave the stock oversize :-)