Slotting and Broaching tool for the Lathe

[jjr2001]

I have tried the "no tool method" by just using a cutoff tool in a tool bit holder and that works but it does
put a lot of stress on the carriage gear train. (Manual Feed Gears). There are a lot of examples on the net
using a dedicated tool in the tool post. I tried that method but with my little lathe rigidity was missing.
So I reverted to mounting the new slotting tool with a tool post riser and removing the compound and QCTP.

The block of aluminum is 3" by 4" and about 1.75" thick. The bushings are 3/4" ID and 1" OD.
The hole for the bushings was simply bored straight through. I added a hole (set screw plug) in the top
of the tool body so that I could fill the area surrounding the ram with oil. The bushings were a slip fit and
then I set them with blue loctite so the oil does not leak out.

Ram is 3/4 drill rod with factory finish and it is a nice sliding fit in the 3/4" bushings. The handle is 1018 steel
and is 3/4" wide and 1/4" thick. I used either shoulder screws or allen cap screws for all fasteners. The link is
a chunk of brass that is kept well lubed in use.

First trials with it mounted on the riser showed that it would rotate against the riser when high forces were applied.
I solved that with the little steel clamp that locks the slotting tool block to the riser. Works fine now.

The boring bar type tool holder was going to be the tool bit holder of choice but after trying my "rota-broach" type
tool bit I think they will be fine for some types of work.

There is a test piece in the chuck in a couple of pictures. The nice thing is that this tool will broach out a round hole to
be square by using one of my square broaches. The square broach can be used internally or externally. I was also able
to make the square broached hole larger by rotating the chuck 90 degrees and moving the cross slide in a few thou at a time.
Then by moving the tool up or down with shims the square cut could be enlarged to whatever you wanted. Using the smaller
tool bit and enlarging the square hole with it will keep the forces lower than if going to a large bit.

I need to make more tool bits for smaller sizes and will do that next. It looks like the tool will be very useful
putting keyways in gears and shafts for my model engines.

Cheers, JR