Hi Capnahab, Looking at you photo's you have already been cutting threads? so you need to take one of two routes, either buy tips of the correct form you need or grind your own tools.

Grinding your own is not difficult even free hand, you need to buy yourself a gauge like this one **LINK** and use this to gauge your tools, you may not get perfection without a shadowgraph but you will make tools more than adequate for model engineering use. I will send you some photo's of some of mine tomorrow. You will need both 55deg and 60deg tools but you will have to truncate Whit, BSF & UN threads to accommodate the crest radii, for Metric this is not required. The gauge you will also need to set your tools in the lathe.

Alternately you can use disposable tips and you have a choice of full form or just the standard tips which are in essence similar to home ground tools in that you will have to truncate the thread. Full form does what it says on the tin — it cuts a full form thread including all radii.

For full form you need a tip for each thread pitch and form so it can be quite expensive but with standard tips you need only a small selection of each form 55 or 60 deg but you will need some with different tip radii, you could not for example use a 12tip tip with correct radii to cut a 20tpi thread but although not correct you could use a 20tpi tip to cut a 12tpi thread, obviously the root radii would be incorrect but the thread would work OK.

As far as purchasing the correct tips I would recommend using a good toll supplire who will guide you to the right product–either your local engineering supply house or MSC Supplies, Greenwood tools etc. Yes you will pay more but you will get the right grade and a tool that will do what you want. Remember you are buying 3 tools on each tip.

Sorry for rambling on but hope you glean some info from this.

John