Dave, have you get any pictures of the existing setup/quill?
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Dave, have you get any pictures of the existing setup/quill?
A few pics here...
Attachment 19490Attachment 19491Attachment 19489
The weak spot is the joint between the coupler and the quill - there is a flat recess milled on the quill about 15mm dia and i picked up on that face, it really needs more contact above and below the bolt but then you lose more z axis travel and thats bad enough already.
Its the little round boss on the right of this part...
Attachment 19492
How much Z travel would you lose, if you bridged between the current single bolt mounting, and the end of the quill (where you currently clamp on the second spindle bracket)?
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If you were to bridge between the two, then you should get a stable piece to then mount the ball nut to.
I can see where you are coming from here, nice idea and would certain strengthen it 100%.
But as always there is a negative - it would stop me being able to fit the aux spindle.
By having the support on the end of the quill when running as a normal bridgeport, I would maybe lose 12-15mm of travel - not too bad. But to allow me space to fit the aux spindle as well below it, the support would have to be that much further up the quill, probably losing 40mm + of travel permanently - this would cause big issues when doing normal work.
But it is a nice idea though.
Rework the Aux spindle mount, so it attaches to the new adapter?
It's possible, the main draw-back is the loss of the already limited Z travel when doing normal work - this is a big pain in the wotsit really. Not so bad on the aux spindle as all the tools are so short as is the work itself.
To make it really work would need the knee setting up as an axis and diverting all tool-length measurements to that axis - this would mean cutting is done on the quill but the loss of travel would not be as serious.
I still feel the quill rack is a way forwards, won't cost much to try at least.
Maybe a totally stupid off at a tangent idea but could you build an assembly just for that purpose on the other end of the ram, then you could leave it setup and it would not get in the way of normal milling. Sorry, did not see earlier post.
Which purpose?
If you mean the auxiliary spindle - this is only mounted when i need it, that was the whole idea really - its a normal Bridgeport plus a high-speed engraving/milling machine when needed.
The back of the ram was looked at, but adding a full Z-axis of any rigidity would be a considerable task, the aux idea is less cost and means not swivelling the ram.
I have even seen a full linear rail Z axis mounted between the ram and the existing mill head - the user locked the quill up all the time and moved the whole head up and down. Sounds nice but to get it working would not be cheap or easy i feel.
Quill drive idea mk1,
gives a 16:1 reduction, takes up little space, mounts to existing threaded holes on left side of head.
Attachment 19498
Should allow both belts to be tightened by having only one moving shaft.
Anyone have a video or link to some pics of a powered knee mill conversion?
Seems a lot of people rate it but i cant find any proof! http://machsupport.com/forum/Smileys/default/smiley.gif
Still deciding which way to go.