I cross posted this on HM forum, Precision Mathews sub forum because its the 'same' machine but not PM. Thought I'd bounce off you guys in case you have ideas.
I have a (not PM) but likely identical Taiwan 935-VS mill. I'm not sure if I just never noticed a sound that has always been there, or maybe hearing it different recently with the speed set at similar RPM on recent machining op. When I first turn it on, its the silky smooth motor running sound for maybe 5-7 secs. Then it kind of makes a low frequency in & out, low hum, maybe a second in duration, spaced 3 seconds apart at say 1000 rpm. Its not a problematic vibration or anything. If I put my finger on the underside of the cover plate & squint my eyes, it seems to corresponding to where the noise is coming from. If I switch to low gear noise is either gone or barely perceptible (hence my guess rpm/harmonic?).
From what I can see of the parts, schematic, that bottom cover is below where the sliding cone discs & a spring is located. I could readily visualize the spring doing a bit of shimmy like this, although it could be any combination of sliding/moving part.
Any comments? Any advise before removing the cover plate? Will parts come flying out or is it just sealing off the assembly inside? I undid the cap screws, it didn't drop off so thought I'd ask first (but could also just be new machine paint in the crack).There is kind of a circular boss in the casting although I don't think it holds a bearing attached to the drive shaft assembly or anything. I see a (45) spring flange but assume that just retains the spring etc. & not connected to the plate?
I have a (not PM) but likely identical Taiwan 935-VS mill. I'm not sure if I just never noticed a sound that has always been there, or maybe hearing it different recently with the speed set at similar RPM on recent machining op. When I first turn it on, its the silky smooth motor running sound for maybe 5-7 secs. Then it kind of makes a low frequency in & out, low hum, maybe a second in duration, spaced 3 seconds apart at say 1000 rpm. Its not a problematic vibration or anything. If I put my finger on the underside of the cover plate & squint my eyes, it seems to corresponding to where the noise is coming from. If I switch to low gear noise is either gone or barely perceptible (hence my guess rpm/harmonic?).
From what I can see of the parts, schematic, that bottom cover is below where the sliding cone discs & a spring is located. I could readily visualize the spring doing a bit of shimmy like this, although it could be any combination of sliding/moving part.
Any comments? Any advise before removing the cover plate? Will parts come flying out or is it just sealing off the assembly inside? I undid the cap screws, it didn't drop off so thought I'd ask first (but could also just be new machine paint in the crack).There is kind of a circular boss in the casting although I don't think it holds a bearing attached to the drive shaft assembly or anything. I see a (45) spring flange but assume that just retains the spring etc. & not connected to the plate?
