PM 940 Z axis fine feed back lash question

[Sticks]

I have had my mill for about a month now, and the fine feed on the Z axis has 1 full revolution on the hand wheel before the quill engages, which makes it interesting when drilling and plunge milling. I have to tighten the quill lock what I would call excessively to keep it from grabbing, and yet still turn with one hand. I have already trashed 3 carbide endmills, and scrapped two parts from it grabbing and plunging.

Anybody know if this is normal for this model, and is there an adjustment?

PM Tech support response is disassemble and inspect to see why I'm getting so much play.

 

[ddillman]

That is not normal for any model, but I don't know about adjusting it. You will need to disassemble it.

 

[verbotenwhisky]

I have had my mill for about a month now, and the fine feed on the Z axis has 1 full revolution on the hand wheel before the quill engages, which makes it interesting when drilling and plunge milling. I have to tighten the quill lock what I would call excessively to keep it from grabbing, and yet still turn with one hand. I have already trashed 3 carbide endmills, and scrapped two parts from it grabbing and plunging.

Anybody know if this is normal for this model, and is there an adjustment?

PM Tech support response is disassemble and inspect to see why I'm getting so much play.

The only issue I have with my fine feed is occasionally when I release the lock the quill drops substantially so I have gotten in the habit of clearing my work piece before adjustment requiring it be unlocked.

 

[pontiac428]

The quill feed wheel needs to turn a little to engage when you move the feed lever. Give yourself more head room and you shouldn't have an issue. I don't use my quill for most milling procedures, I prefer the knee, reserving the quill for power feed moves like drilling and boring. I don't really like the sound of your quill dropping a little when you plunge, that should not be happening. Perhaps some linkage adjustment is needed?

 

[B2]

fine feed on the Z axis has 1 full revolution on the hand wheel before

I have a PM940M-CNC-VS. Purchased a few years ago. At that time the non-CNC version had a power down feed as well. So I think your newer machine is different from those. However, I suspect that the fine down feed is very similar. On mine there is a big black knob at the center of the larger manual down feed levers. When I tighten up/lock the manual down feed levers via the this friction knob the fine adjustment knob still works but is stiff. Three is some form of clutch in there. I do not notice a large backlash to get started. I think this stiffness/friction is the way it is suppose to be ..... to avoid the problem you have described. I have not actually tried using this fine adjust with an end mill as my machine is CNC and so is not needed. However, I have used it many times to do drilling and it does not grab the work and pull the drill into the work. I have not looked inside to see if there is an adjustment for this friction, but there maybe. I do not try to use the mill with the quill lock loose as there is play in the x and y directions. So even when manually drilling I keep the quill lock pretty snug. This is probably standard practice for most folks.

PS. There is a drawing and photo of your clutch in the PM manual that is downloadable.

Dave L.