Z axis power feed advice sought

[tonyfoale]

I had a bad fall some months back and damaged my left shoulder. I am now starting to get back in the workshop but I find that winding the Z axis crank on a Bridgeport mill is hard going for my left arm. As a result I am considering using a long stroke hydraulic jack to replace the current screw lift but the easiest way would be to buy a ready made electric winder, but I have heard reports of short life spans.

I measured the torque required to wind the handle to be between 90 and 110 inch lbf and the following unit is claimed to be rated for 650 inch lbs. That suggests that it should have a long life span.

This post is directed at those with real world experience with these Z axis winders. Are they worth fitting?

[gatz]

There are other sources for that model , one on Amazon;

https://www.amazon.com/RATTMMOTOR-XY...8&sr=8-19&th=1

Also, if a 460 lbin unit would work;

https://www.amazon.com/dp/B0BTDFBKDD...1zcF9kZXRhaWwy

[tonyfoale]

There are other sources for that model , one on Amazon;

https://www.amazon.com/RATTMMOTOR-XY...8&sr=8-19&th=1

Also, if a 460 lbin unit would work;

https://www.amazon.com/dp/B0BTDFBKDD...1zcF9kZXRhaWwy

Many thanks. You did not answer my question but your links are to much cheaper sources of the same items and that is very useful info. In general I avoid looking at US sources because shipping is so expensive but not in the case of those in your links. Thanks again.

[gatz]

A jack would not retain the gradations for the Z axis, unless you equipped the mill with a DRO on that axis; it would still be quite a challenge to obtain the desired setting.

i adapted a Milwaukee Hole Hawg for just this purpose, but made it easy to put on & take off so that the normal handle or crank.could be used.

link to article…

Power Feed for Knee Bridgeport & Clones

Other people have made adapters for drills or (air) ratchet wrenches. Much simpler.


Do a google search for

Z-axis crank

[albertq]

Hi Tony, yes those Z-axis power feeds for raising and lowering the table are very useful. I use mine all the time and saves all that hand winding whilst keeping handle pressed to stop spring disengaging the handle. I would definitely recommend it if you frequently need to raise and lower the table to accommodate the job and the tool length. It has rapid up and down and speed control knob so easy to use.

[metric_taper]

I purchased the same import unit (Align brand from Harbor Freight) >20 years ago and put it on my Wells-Index mill. It absolutely (I'm age 67) was the right thing to put on the mill.
I did have to make a new shaft to the bevel gear that mates with the lift jack screw on the knee. I also made a mounting stand (I think that's what it's called) that replaced the original dial scale 'tick' mark and bearing access cover for the shaft. I pulled the original one out, I think I used some 3/4" bar stock to copy the original bearing lands and bevel gear pilot and flat for a set-screw (which I thought was odd for the torque needed to hand cranking).
I needed the new shaft for the extended length (I used some 4inch round bar that was 1.25" thick cutoff for the mounting stand), also to make clearance for the cross feed power unit (which is rotated at a 45 degree angle for the fwd/rev feed lever, which I had to shorten). This feed unit needed the table lift to be further out to give that clearance.
At the end of the new longer shaft I put the original crank handle. I do use that for the exercise. But the power feed makes quick work raising up the knee. I keep my 12" rotab with 3jaw chuck stored on the left end of the table, and mostly have the 6" machine vise on the mid right side of the table.
Sorry for the long story. I've not had a single issue with any of these import power feeds. They did a better job at copying Servo brand's mechanism. And they all have the problem of a very small sweet spot of feed control on the potentiometer. There's no feed back even in the Servo brand power feed. Just a PWM SCR (in the table feeds 150inlb, TRIAC in the table feed 250+inlb) simple circuit using the mains frequency as the PWM frequency. Either no movement, to too fast with less then 10degrees of the speed pot angle from slow to fast.
They all use universal brushed motors. And the biggest part of the fwd/rev mechanism is levers with cams to control microswitches, and swaps the electrical ends of the field windings in the circuit.
I don't think you can go wrong.

[tonyfoale]

I purchased the same import unit (Align brand from Harbor Freight) >20 years ago and put it on my Wells-Index mill. It absolutely (I'm age 67) was the right thing to put on the mill. .

67, a mere child then? I'm only 80.