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Best way to couple motor to lead screw

X-Y table has two X-axis handles so X lead screw is bushed at both ends. Y-axis is bushed only at the front, rear end of Y lead screw floats (not bushed) and does not extend beyond housing. I'm able to couple motor shaft to lead screws quite easily by removing any handle and using a suitable coupler. However, for the Y-axis, it's preferred to drive the screw at the rear instead of the front where the handle would normally be. Does this make any sense;

  1. Drill and tap rear of Y screw dead center (machine shop)
  2. Cut head off partially threaded cap bolt with matching size thread
  3. Screw bolt into rear of Y screw
  4. Support bolt using matching sleeve bearing (or self aligning bearing) in pillar block type support
  5. Couple motor shaft to bolt using flexible coupler if necessary
Reply to
oparr
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How about:

  1. Have machine shop turn down back end of lead screw to fit flexible coupling.
  2. Independently mount motor in appropriate position using a bent-to-fit bracket.
  3. Mount leadscrew-coupling-motor-bracket.

Fred

Reply to
Fred R

Motor needs to be at least 5" from rear of lead screw (saddle clerance limitati>

Reply to
oparr

OK. coupling - short shaft - coupling - motor This avoids misalignment loads on motor while providing torsional stiffness in both directions of rotation. The lead screw is not perfectly straight, plus it will see thermal expansion. It also will be displaced from the motor shaft by both an offset and an angle.

The motor bearings will thank you and reward you with long life - theirs.

Fred

Reply to
Fred R

OK. coupling - short shaft - coupling - motor This avoids misalignment loads on motor while providing torsional stiffness in both directions of rotation. The lead screw is not perfectly straight, plus it will see thermal expansion. It also will be displaced from the motor shaft by both an offset and an angle.

The motor bearings will thank you and reward you with long life - theirs.

Fred

Reply to
Fred R

Thanks for your suggestions but I don't want to cut the lead screw other than facing off a mm or so. Still favoring rigid shaft extension and no doubt the machine shop will suggest installing an oversized rod then cutting it down to size while turning the lead screw to minimize runout.

The motor will be mounted using a 1/4" rubber "gasket". This is in addition to flexible coupling.

Motors are $25.00 a pop and their 1/4" sleeve bearings are $4.00 a pop. The brushes may go before the bearings anyway.

Reply to
oparr

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