Ryobi Pillar drill RDP5016s

[Nozzle]

A place like Bearing Boys will flog you some belts. Measure up roughly whether it's size A B Z etc, then the length then just buy a few that are similar sizes if you're concerned your measurement isn't accurate enough

Nozzle

 

[SFK]

Nozel,
Bearing Boys are a great suggestion, but the middle pulley is free to move, the motor has a tensioning movement, there are multiple pulley combintations and you need the inside diameter of the pully.
I think I would find that hard to measure.

But if I was to I would use the following system of ONLY measuring the diameter of the inside of the pulley, and the lengh between the front and back pulleys (never to middle pulley) when the mortor is in a central tensioning position.

So assuming
π = PI , 3.14
d = diameter of the inside half way up grove of the pulley
l = length between the front and back pulleys (never to middle pulley).

For a 2 pulley system you need one belt with:
Length = Circumference + (2 x the length between the pulleys)
Length = πd + 2l

or for a 3 pulley system you need two belts each with:
Length = Circumference + ((2 x the length between the pulleys) divided by 2) >>>as the middle pulley is at halfway so half as much needed.
Length = πd + l


Tiger, with your coment that 'mechanical things is not my forte', I would try the two bits of string first:
1) With a bit spare at each end, make two pen marks 31inches appart whilst the string is straight.
2) Then tie string together, using the spare end bits to make the knot, trying to make the sure the two pen marks touch each other as you tie the knot.

SFK

 

[lostinthelight]

If the diameters of drive and mid pulleys are not too different then a less complex way if there is a clear path would be to ditch the mid pulley ?
After reading the data plate of drilling capacities, there should be adequate number of speed variations from the two remaining ones for most uses ?

 

[Burnerman]

I hinted at that one in #16 - it may be necessary to remove the central pulley though.
For sure, it will make calculating the belt length simpler......I can't say I've ever come across this arrangement before - more common being 6 stepped pulleys.
John

 

[lostinthelight]

I hinted at that one in #16 - it may be necessary to remove the central pulley though.
For sure, it will make calculating the belt length simpler......I can't say I've ever come across this arrangement before - more common being 6 stepped pulleys.
John

Sorry missed that one John..mind fogged on a 4”screen at the early hour and those n’s d’s and l’s . I’m not that good with formula and calcs but use cut old belts or the OH’s sewing tape to measure...and what about pitch circle diameters which is where some suppliers quote their sizes by?

 

[Burnerman]

Using an old, cut belt....now that is an idea!
Can't say I've heard about PCD specifications though......I have a Eriks outlet not too far away and more often than not they give me a belt one size either side of my calculations - as I always get it wrong
Eriks took over J H Fenner power transmissions - both excellent companies and it didn't matter to them whether you wanted a mower belt or a 3' bearing for a ship propeller
John

 

[lostinthelight]

Ive found in the past that a belt say marked as B46 could be different lengths from different manufacturers depending on where they measure from
https://www.linearmotiontips.com/v-belt-pitch-length-datum-length/

 

[Tigger90]

After googling and measuring and not finding any real information on the pillar drill I contacted the seller and asked if I could return it. They accepted, the drill has been returned and I have my £20 back
Thanks all for your help