TRIAC Mill Spindle Project



Here are my drawings of the project so far.

Its basically two pairs of angular contact bearings mounted back to back and separated with a distance that will rotate with the spindle axle. The lower pair will be held in place and the upper pair will be able to slide inside the housing with heat expansion.

There will be centrifugal seals both at the top and the bottom the spindle. These will be aided with clean air that is introduced tangentially with the spindle axle at the tool side. This air will circulate with the spindle and at the same time push outwards and hopefully take coolant and dust with it and thus away from my precious bearings. Some air will go the other way, upwards in the spindle, through the bearings (that is why the air needs to be CLEAN) and out through the top seal where is will work the same way as in the bottom.

Hopefully the air will also act as cooling for the spindle. And as I intend to use grease in the bearings I do not think that it will harm the bearing lubrication.

I have not yet decided on material in the housing. I plan to outsource that part and thus I can choose more freely and no being kept to what I can machine.

Another question-mark is the thickness of the housing around the upper pair of bearings. As I will retrofit my existing mill with this spindle I am forced keep within certain measurements and

this make the upper part of the house a bit skinny for my liking. I do have a choice to mill out material from my head and make a little more room, but I rather keep the alternative to go back to the old setup in worst case. The outer diameters of the housing are, 100mm, 80mm, 73 mm. The inside upper diameter is 62 mm. This leave a wall that is just some 5.5 mm thick. I can perhaps get it to run the 80 mm outer diameter all the way up, thus increasing the wall to around 9 mm. Not sure which way to go. Have to check the mill head before I decide

More speed, more power, more movement, more coolant, more light..