Threading Inserts

[19brendan81]

I see that Hare and Forbes have threading inserts available for carbide tool holders. These appeal to me as im not cutting good threads at the moment and I want to eliminate my HSS grinding skills as one of the reasons.

Will a 60 degree insert allow me to cut all metric threads and a 55 degree one allow me to cut all inferior threads or do I need multiple of each depending on the thread I wish to cut?

Thanks in advance.

Brendan

[bollie7]

Brendan
60deg will cover Metric and Unified (UNC, UNF and variations) 55deg covers Whitworth (BSW) and British Std Fine (BSF).
Seriously though, if you want to save yourself plenty of money over time, learn how to grind HSS. Its not hard to do once you get the hang of it. Once you have a few thread tips ground up they will last you a long time with minor touch ups on the grinder.
Even if you stick with inserts there will eventually be a thread you need to turn where for one reason or another you won't be able to use an insert.
ie I once had to make a new cross slide nut for an old lathe. the nut was phos bronze (cause I had some) being an old machine it was an imperial thread. the thread in this case was an acme, left hand, about 1&1/4" long with and OD of 5/8". this meant the hole was about 1/2" ID
I roughed out the tool shape on a small bit of HSS, welded it to the end of a 1/4" Hi tensile bolt and then finish ground the tool shape. then cut the thread. Had to make a lot of passes on the same settings to work the spring in the bar out, but eventually got the job done. The old lathe is still work 18 years later.
Learn how to grind tools mate , you will not regret it. When you start off, just use some mild steel square bar if you can find some. once you get the hang of grinding the shape move onto the more expensive HSS.

regards
bollie7

[19brendan81]

Cheers Bollie,

Im going to use those inserts for now, and when I need to cut something odd i'll use HSS.....like for instance on the ACME thread I intend to cut for a home made grain mill that is in the pipeline.

Brendan

[.RC.]

decent quality threading inserts are also around $30 a pop...

[Retromilling]

If you want to cut a wide range of thread depths with an insert then you would be better off getting the partial form inserts and not the full form inserts.
Also don't get an insert for a fine thread and expect it to be deep enough for a much coarser and deeper thread form.
Buy a partial form insert for the deepest thread you will need and only cut as deep as each thread requires .