Need help with making lathe tools

[arnoldb]

Judging by your pictures there's no real rule on how to make these things, you just make them to suit the job?

You got it spot-on. It depends on all the same factors as for external tools; What do you need it to do; what material are you trying to machine etc. etc. Rigidity plays a much bigger role with boring bars as well; one needs to keep them as short and thick as possible for a given job.

Regards, Arnold

 

[Dirty_Vinylpusher]

And how about a parting tool....

You made any of them?

 

[Tin Falcon]

I prefer the commercial T style cut off tools but have ground tools for small to tiny grooves.
Tin

 

[arnoldb]

I have a small lelection of home-made parting tools - no commercial ones

The blade on the far left is HSS from a wood planing machine; the parting tool on the far right is a bit of this blade that I cut off and ground into my everyday-use parting tool (it's mounted on the rear toolpost). With this one, I can easily part of through a piece of 60mm ali bar. Have only tried it on 32mm steel so far but I think it will do bigger. The parting tool second from left is a ground down bi-metal steel cutting jig saw blade; I use it for parting of small bits; predominantly 2mm brass nuts that I seem to be making a lot of... The third parting tool is the oldest one in my collection and served on the front toolpost for a year or so. You'll see that it has a generous chip breaker ground in; that works well for parting of aluminium. The "curve" on its bottom is from a dig-in at one point; it broke off in that curve shape :

Regards, Arnold