As a starting point I made a sketch to see where it was going and what was required. The sketch below shows cooling fins, but it turned out to be over the top so I made it plain instead.
I started out using a ready-made blank end MT 2 arbor. The reason is that I do not have any taper turning attachment, yet, for my C3.
I made a hole big enough to drop in a thrust needle roller bearing and then turned a brass bushing that acts as radial bearing. The thrust bearing dimensions are 21x4x8 mm and consequently, the hole is 21 mm and a bit in diameter. The hole is 25 mm deep and the bearing requires 4 mm so I made the bushing just under 21 mm long to avoid fouling the bearing.
The bearing dropped in in the following picture.
The last washer is still missing. The washer is hardened as it is against this that the rollers run and you do not want it to ware.
Next up was the brass bushing. I made the hole 12 mm diameter which I reamed to be able to use 12 mm dia sliver steel (drill rod). I also added a short collar to stop the bushing from falling down to the bearing. Then a screw locks the brass bushing to the body.
The hole is countesunk to fit a cheese head screw.
Here the screw is in place and as can be seen, I drilled an oil hole right through the screw to lubricate the rotating tip and the roller bearing. A spot of pil keeps temperatures down.
At this point the body is done and it is time for the tips. The first one is a "tip" with an M14x1 nose and a tommy bar hole. This gives me a possibility to mount any chuck or face plate from the MJ-189 as work support. The nose then has a 12 mm end taht fits into the center body.
The tommy bar hole is of course used to remove the attachment from the arbor. The shaft that goes into the body is slightly longer than 21 mm so that the tip sits against the roller bearings outer washer and gets a good thrust support.
In the picture we see the drill chuck attached, but an ordinary 3-jaw works just as well ...
... or a 4-jaw, ...
... or a face plate of some sort. Using this tip will enable several possibilities to support unusual or otherwise difficult set ups.
Imagination is the only limitation. There are a few more tips to make such as:
- An ordinary but thinner center for close work.
- A female center for pointy or thin jobs.
- A pipe center with a large diameter.
- A few differently sixed push plates to use with threading dies.
Sketchers and drawings on the different parts are shown below. Please be aware that the shafts are not 10 mm but 12 mm. The shaft length is 20 mm instead of 22 mm. The best material for the tips is 12 mm silver steel (drill rod) which fits directly into the hole in the body.
When body and tips are done it is also very useful to make a small tray where each part has its own place. Then the risk of loosing an item is less.
The above sketch gives a suggestion for a useful tray.
Another very useful accessori for the C3 has been made.
/Peter
