Tools for Super 7

Easy sharpening.

Easy centre height resetting.

Unless you get a piece of HSS that's prone to chipping along the length of the bar... took me ages to figure out why it was going blunt so fast!

Neil

A couple of recent postings give details of how to make up a tangential tool having a rhombus shaped shank set at 12 degrees. How critical is this setting and on what basis is it derived?

All the Tangential tools I’ve seen have had Square section shanks. The general advice I read many years ago was for the bit to tip 12° forward and 12° to the left as you face the machine. I’ve made several to that spec and they work fine. Anyone tried anything different?

This is the last one I made.

I use a piece of 1/4" square "Stellite" in my tangential tool holder, I always sharpen it on the side of the wheel so I get a flat cutting face and then keep a really keen edge with an occasional touch up with one of those cheap diamond hand file thingy's.

Unless I need a specific shaped form tool for something, this is my "Go To" tool every time now. The surface finish it produces is superb. The Stellite tends to keep a sharp edge for much longer than regular HSS tool steel.

Phil

I may have a jaundiced view of this opinion owing to my Super 7 being a Long Bed model and having a VFD and 1hp 3 phase motor, but using insert tooling I regularly take 10mm reduction cuts on 30mm stainless bar with blue chips flying.
If you need to save money, have short arms & long pockets or have plenty of time to play at a grinder and shimming tools coupled with insufficient work to keep you going until you drop off your log then inserted tooling may not be for you.
If you want to be able to rotate or swap a worn or chipped edge in seconds and carry on with your work then inserted tooling just might be for you, the variety of forms available means that most of what the naysayers trot out on this subject is woefully out of date.

Just to clarify:

I use CCMT0604 tips for roughing. The 100 degree corner, to use the tips where I have chipped the 80 degree corners, usually by being careless and banging the tool into the work. (An activity that can be expensive! )
The swarf comes off a lovely shade of brown or deep blue, when roughing, and leaves quite a good finish. Although high speed, high volume production work is what carbide tools were originally designed to serve.

A CCMT0604 tip is used in the Boring Bar, and produces very good finishes, with a fine feed.

The tangential tool is used for for finishing, since a freshly sharpened toolbit will take a cut of 0.0005" (0.0127 mm ) or so!

According to Eccentric Engineering, their tool holder can be used to hold round toolbits, or ones ground for screwcutting.

You use whatever works best for you, with your equipment and materials.

Howard

Stellite particularly has a 'favourite' orientation. If you look at a new piece it will have a small notch ground on one edge at the end. This should be the upper edge when being used conventionally as it's the strongest orientation.

Doesn't affect your tangential use just a FYI.

Yes that’s right. Someone gave me a couple of old broken solid carbide mills so I use one in the Eccentric tool for cutting hard stuff like cast Iron or HSS.