Mk2 Tangential Tool Holders

Having made my new tool post and proved that it worked well, I wanted to update my old tangential tool to work with the new tool post. While I was at it, I made an additional one with a different design.

These were machined from the same 50 mm × 50 mm bar of EN1A that was used for the body. This was a little wasteful as 50 mm × 32 mm would have been more appropriate, but I was keen to take advantage of the better machinability of EN1A compared to EN3 or EN32. I only really needed one tangential tool holder as I was simply wanting to replace my existing holder with some minor improvements. However, since the methodology of making these tool holders requires two to be made at a time, I thought it would be interesting to try something a bit different with the "spare" holder.

Conventional Tangential Tool Holder

The first tangential tool holder is similar to my existing holder, except that the part that attaches to the tool post and the part that holds the tool bit are a single piece (rather than being screwed together). This makes the manufacture more complicated (especially tapping the holes for the retention screws), but allows for material removal along the top of the tool holder. This provides a reference surface. When the tool bit is placed in the tool holder, the tool holder is held on a flat surface such that the tool tip is on the same plane as the reference surface. The tool holder is then set for centre height and every time the tool is removed and resharpened, the tool can be easily re-set to the correct height.

If you have a relatively modern browser, you should be able to drag the model below around with your mouse to look at it from different angles. Note that the model is relatively large so it might take a little while to fully load all the parts.

It seems you are using an outdated browser that does not support canvas :-(

Round Tangential Tool Holder

One of the key advantages of the tangential tool holder is that it is very easy to sharpen (and re-sharpen) the tool bit. This is especially true with a quick change tool post and even more so with a reference surface so the tool can be replaced in exactly the same position every time. One of the other tools I use a lot is a tool with a large radius cutting tip. This is described in Harold Hall's excellent introduction to lathe use (see SK2 on page 18 and photo 4 on page 23). This can only take very fine cuts, but produces a beautiful finish. However, it needs to be sharpened regularly and is a little awkward to get exactly on centre height as it is typically set up for turning rather than facing. As an experimental alternative to this, I decided to make a tangential tool holder for a piece of 8 mm diameter HSS. While the normal benefit of a tangential tool holder of being able to take deep cuts doesn't really apply to this tool, it is extremely easy to sharpen (with the same sharpening jig as used for the normal tangential tool) and it uses a simple reference surface on the holder to ensure a consistent centre height. It is easier to make than the conventional tangential holder as it only has a simple 12° angle rather than the compound angles seen in the conventional tangential holder.

If you have a relatively modern browser, you should be able to drag the model below around with your mouse to look at it from different angles. Note that the model is relatively large so it might take a little while to fully load all the parts.

It seems you are using an outdated browser that does not support canvas :-(