x2 belt drive conversion nightmare

so my x2 gearbox went south..again. bought a belt drive conversion and what a disaster. Drive ratio in low is far too high for boring and it slips alot. Now going to repair gear box!

I converted my machine a few months after buying it and couldn't fault it - kit from lms .

I find the motor will overload before the belt slips and i do push that little mill way beyond its design parameters !

Are you sure you have the pulleys set up correctly ?

Ian .

I made my own conversion based on Jerry Rollets design....

Found the lower speed fine for boring....One of the first boring jobs I used it with, was make the large holes in some 2" square when I made my Harold Hall spin indexer.....

Im mostly trying to bore and drill copper which is prone to snagging no matter how much milk you throw at it. I love the quiet running but despite machining the small pulley down as far as possible it is still much higher geared than the original gearbox was and is now quite useless for me. I need a bigger machine!

There does sound if there is something wrong, as with John I built the Jerry Rollets design and find the speed for boring fine, and like Ian the belt never slips but the overload switches it off if I push it too far.

John

What pulley ratio is it?

Mine is geared somewhere a between 3:1 and 4:1 and have no problem using a boring head at about 60-70 rpm.

Neil

Dont know the ratio but turned the drive pulley down as far as possible but still higher geared than the original gear box

I need a bigger machine!

You just need more torque, which is gearing down

Aiming at 30-50 rpm is the way to go with most standard speed motors (1450rpm)

Edited By Ady1 on 04/05/2017 01:13:14

You answered your own question - go find a good used bigger machine. More HP with steel gearing or heavy V belts (as in a Bridgeport or similar) will cope with most anything you throw at it. JD

There is a range of hi torque motors for these machines right up to 1400W....but at silly prices. Any ideas for an alternative?

.

Yes,

Get the reduction ratio of your belt-drive sorted

... You may need to use Poly-Vee pulleys & belts

MichaelG.

Even the hi-torque motors only go to 100rpm, and a long tough job will risk cooking it

If you want real torque it's got to be a simple motor and gearing down system like they use on a lathe headstock

Thinking out of the box could you use a lathe for roughing out and the x2 to finish?

Reducing the diameter of the driving pulley is only half the story......

Dont forget, the original drive train......geared motor driving layshaft, thats the first reduction..... Then there are the two gears for high and low speed....driving the spindle.

The belt conversion drives directly from the motor to the spindle, so you have effectively missed out the layshaft reduction.

Edited By John Rudd on 06/05/2017 09:14:07

I used a timing belt and pulleys on my xj12-300 variation (3/4hp motor) and haven`t really had a problem with it ,but i have a bigger mill now as well.

Hi I had similar problems with an X2 Mill Drill so I ditched the gear drive and progressed to a Poly Vee Belt Drive and a 1.25 hp Treadmill Motor and a AC to DC reversing controller.

PM me if you want more detailed drawings in dxf or pdf format

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Eric