PM 932 PDF quill downfeed levers.

[av8ter]

Hello. Somewhat new to the group and my first post here. I have a PM 1236 and a PM 932 PDF. My question is about the 932. When running the fine down feed or power down feed with the quill downfeed levers out they like to fall back to the manual (course) position. I have some parts I make that are cut at 30 degrees so with the head tipped over that much it happens every cut. Has anyone ever modified and installed some kind of detent spring/ball type of thing?

 

[9t8z28]

I just had the powerfeed gearbox off and although I did not take apart the handwheel assembly I am not sure if it is possible to add a spring or detent. On a slightly different topic, I have wanted to make the handles 2 piece so that I can remove one when it gets in the way of the work. Do you think its the weight of the handle (gravity) that is causing it to disengage or is it vibration?

 

[av8ter]

I just had the powerfeed gearbox off and although I did not take apart the handwheel assembly I am not sure if it is possible to add a spring or detent. On a slightly different topic, I have wanted to make the handles 2 piece so that I can remove one when it gets in the way of the work. Do you think its the weight of the handle (gravity) that is causing it to disengage or is it vibration?

I think it's a little of both. When the head is tilted over 30 degrees it really does it a lot. Not so bad with it at 90 straight up. Only kicks out now and then. Shorter handles would keep them out of the way of work but would also require more effort to manually run the quill down. Depending on whether or not one had eaten their Wheaties it might not be an issue. I have been able to just run the head up or down the column some to position the feed handles out of the way but I will eventually run into a job that won't fix the problem. I did unscrew one of the plastic knobs once for clearance.

 

[9t8z28]

I think it's a little of both. When the head is tilted over 30 degrees it really does it a lot. Not so bad with it at 90 straight up. Only kicks out now and then. Shorter handles would keep them out of the way of work but would also require more effort to manually run the quill down. Depending on whether or not one had eaten their Wheaties it might not be an issue. I have been able to just run the head up or down the column some to position the feed handles out of the way but I will eventually run into a job that won't fix the problem. I did unscrew one of the plastic knobs once for clearance.

If it still disengages at 90 degrees then I would think that something other than the weight of the handle and vibration is causing it. When I disengage the downfeed on my mill it doesn't pop out easy. I have to give it some force. Maybe I can try to measure the force required to move the handles. I have a scale that goes to 14lbs. I hope it will be enough.
Have you had your power downfeed gearbox off to clean it?
Also, not sure if you have had your handwheels off yet but all you have to do is remove the allen head bolt and pull it up. You might have to wiggle it a bit for it to come off
When I mentioned shortening the handles, I meant only to remove the handle when it got in the way of the work such as when milling at a specific depth and traversing the X-axis. Sometimes the handle gets in the way. If I was to be drilling I would re-install the handle for that opp.

 

[av8ter]

If it still disengages at 90 degrees then I would think that something other than the weight of the handle and vibration is causing it. When I disengage the downfeed on my mill it doesn't pop out easy. I have to give it some force. Maybe I can try to measure the force required to move the handles. I have a scale that goes to 14lbs. I hope it will be enough.
Have you had your power downfeed gearbox off to clean it?
Also, not sure if you have had your handwheels off yet but all you have to do is remove the allen head bolt and pull it up. You might have to wiggle it a bit for it to come off
When I mentioned shortening the handles, I meant only to remove the handle when it got in the way of the work such as when milling at a specific depth and traversing the X-axis. Sometimes the handle gets in the way. If I was to be drilling I would re-install the handle for that opp.

If you come up with a way to make the handles easy on-easy off please post it up. That would be handy and from the sound of it that is a common complaint. I've had the whole mill apart. I didn't tear down motors but everything else came apart. My power downfeed levers move very easy. I bet it only takes a pound or two to move the levers. I'm sure vibration is the issue.

 

[9t8z28]

If you come up with a way to make the handles easy on-easy off please post it up. That would be handy and from the sound of it that is a common complaint. I've had the whole mill apart. I didn't tear down motors but everything else came apart. My power downfeed levers move very easy. I bet it only takes a pound or two to move the levers. I'm sure vibration is the issue.

I will post it here when I mod it. All I am going to do is cut off both arms, only leaving an inch or 2. Then I will turn down and thread the od of the stub. Lastly I will make new handles keeping the length the same as the originals. The only problem I foresee is getting the handles off. Those knurled pins are stubborn. I hit em pretty good and they didn't budge. Have you had your handles off?
Tonight I will measure the force to disengage the powerfeed and report back here. Maybe Ill even pull the entire handwheel off again and have a better look at the mechanism.

 

[9t8z28]

Last night I used a trigger pull gauge to measure the force required to disengage the powerfeed handles. I got slightly mixed results. .25lbs. to .5lbs. was the most consistent force required to disengage the handle but on occasion I got 2lbs. I tested both handwheels individually with the arm engaged pointing straight down and the gauge horizontal while pulling towards the X-axis powefeed. Keep in mind that I have removed the long cylindrical handles and replaced mine with 1.5" plastic balls so there is a difference of about 3" where the force was applied.
While performing this test I thought of a way you might be able to temporarily fix the issue. Take 2 rubber bands and slide each one down the handle. Connect the 2 bands by either tying them together or use a zip tie to secure them together. You could also try and move the bands up the handle further but you would need to put a spacer so the rubber band pulls straight back on the handwheel. I know most will think this is stupid and would never do this to their machine but it's just to get you out of a pinch.
I did not pull off and take apart the handwheel assembly but I am thinking maybe you can install a spring behind the clutch actuator inside the handwheel hub. If there is enough space or a provision behind the clutch actuator, maybe you could use a spring with just enough pressure to keep the handwheels engaged and not create any biding issues with the normal operation of the mechanism.