Lead out hum

[tjarkpär]

Hi,

our VMS70 with pitch13 does leave some hum/noise in the lead out, which is pretty annoying. During the cut it is fine, but when the motor speeds up, this becomes an issue.

Anybody got an idea how to get rid of it? Maxon motor is fixed on a mdf plate. Already tried loosening and tightening the belt but this is not doing it. Cant find any related threads on the forum.

Here is a rather noisy recording of a TP:

https://soundcloud.com/tjarkpaer/lead-out-hum

Thanks for your help!

[misjah]

Add rubber/padding between lathe body and motor mount and motor…the thicker the better. Using other material than mdc will help too (mine are thick all)….You won’t get rid of it all though.

[tjarkpär]

Add rubber/padding between lathe body and motor mount and motor…the thicker the better. Using other material than mdc will help too (mine are thick all)….You won’t get rid of it all though.

Thanks misjah - got a steel plate mount now and the hum is way less and lower in frequency!

[Dub Studio]

Perhaps some sort of flywheel might help.

Motor noise is usually caused by cogging, and a flywheel is essentially a form of low-pass filter. The mass of the wheel increases the inertia of the motor, which filters out sudden changes in speed (like cogging).

The only drawback with this method is that the flywheel might filter out the changes in speed that you actually want, so careful selection of the weight of the wheel will be crucial... heavy enough to filter out motor noise, but not so heavy that it slows your motor down at crucial changes in pitch.

[Radardoug]

I am sure a VMS70 would not have had this problem originally, so what have you changed?

[andybee]

after 50 years, you should replace this motors & pitch computer by something better...

[Dub Studio]

after 50 years, you should replace this motors & pitch computer by something better...

Could the Maxon be that old?

[andybee]

there are some 30years old arround, still perfectly running, but men´s will is his heaven