Belt drive to Lathe Spindle

[Richard]

I have a Denford Viceroy lathe. For those not aware this lathe has a
link-belt drive from the countershaft then gearing for full speed and
back gear. All of the gears are in mesh and running whilst in either
option. This means that it is irritatingly noisy (and I am going deaf!).
The racket is exacerbated by the fact that some gears have missing or
repaired teeth.
The link-belt ends up with oil on it from lubrication of the gears and
bearings which means that I get belt slip under load.
I am thinking of removing all of the gearing and driving the spindle
with either a timing belt or a mult vee belt. I appreciate that the
spindle has to be removed to allow a belt to be fitted or replaced.
The motor is 0.75Kw 3 phase and I have an Allen Bradley inverter
controlling.
Has anyone done something similar and would like to comment?
Thanks for the interest.
Richard

[David Billington]

Post by Richard
I have a Denford Viceroy lathe. For those not aware this lathe has a
link-belt drive from the countershaft then gearing for full speed and
back gear. All of the gears are in mesh and running whilst in either
option. This means that it is irritatingly noisy (and I am going
deaf!). The racket is exacerbated by the fact that some gears have
missing or repaired teeth.
The link-belt ends up with oil on it from lubrication of the gears and
bearings which means that I get belt slip under load.
I am thinking of removing all of the gearing and driving the spindle
with either a timing belt or a mult vee belt. I appreciate that the
spindle has to be removed to allow a belt to be fitted or replaced.
The motor is 0.75Kw 3 phase and I have an Allen Bradley inverter
controlling.
Has anyone done something similar and would like to comment?
Thanks for the interest.
Richard

I can't help with any experience of modifying a Denford lathe but
Contitech have a detailed design guide for poly V belt drives which is
pretty comprehensive and I have used it on a few occasions in the past
see http://www.powerparts.it/contitech_pdf/CONTITECH_multirib.pdf . Pay
particular attention to the details about driving and driven ratio as it
may be beneficial as IIRC above a certain ratio the driven can be a
plain rather than poly V pulley which simplifies the drive. I've done
that myself using the outside of a brake drum as the driven element and
all worked well. I have also machined my own poly V pulley using a
single point tool to cut the grooves and the DRO for spacing, worked well.

[Richard]

Post by David Billington

Post by Richard
I have a Denford Viceroy lathe. For those not aware this lathe has a
link-belt drive from the countershaft then gearing for full speed and
back gear. All of the gears are in mesh and running whilst in either
option. This means that it is irritatingly noisy (and I am going
deaf!). The racket is exacerbated by the fact that some gears have
missing or repaired teeth.
The link-belt ends up with oil on it from lubrication of the gears and
bearings which means that I get belt slip under load.
I am thinking of removing all of the gearing and driving the spindle
with either a timing belt or a mult vee belt. I appreciate that the
spindle has to be removed to allow a belt to be fitted or replaced.
The motor is 0.75Kw 3 phase and I have an Allen Bradley inverter
controlling.
Has anyone done something similar and would like to comment?
Thanks for the interest.
Richard

I can't help with any experience of modifying a Denford lathe but
Contitech have a detailed design guide for poly V belt drives which is
pretty comprehensive and I have used it on a few occasions in the past
see http://www.powerparts.it/contitech_pdf/CONTITECH_multirib.pdf . Pay
particular attention to the details about driving and driven ratio as it
may be beneficial as IIRC above a certain ratio the driven can be a
plain rather than poly V pulley which simplifies the drive. I've done
that myself using the outside of a brake drum as the driven element and
all worked well. I have also machined my own poly V pulley using a
single point tool to cut the grooves and the DRO for spacing, worked well.

Thanks for the interest David. I have used the Gates drive calculator.
My ratio is only 2:1 so I do need to groove both pulleys unfortunately.
I have used Micro-V before, I designed a belt drive for my X2 mill and
machined all of the pulleys myself so like you I am quite happy with the
machining, still have the tool I ground! It looks as though I need to
lose the minimum speed pulley on the cone to gain enough room for the belt.
Richard