Fitting a backgear to a variable speed lathe.

[Mark P.Participant @markp]

[Mark P.Participant @markp]

Hello all, I have been thinking about fitting a backgear to my Warco WM250 lathe,my thoughts were to increase the torque available at low revs.Anyone got any thoughts on the subject eg. pros, cons and practicality of this idea?

 

Regards Pailo.

[Steve WithnellParticipant @stevewithnell34426]

Hi Pailo,

 

Sort of did this on my Sieg C6, not a “back gear” but added an extra ratio to give me torque at the bottom end – it was easy to do on Sieg, but part of that was down to ArcEurotrade being excellent on spares provisioning.

 

The Sieg C6 was in two versions, a conventional six speed belt drive and a variable 0-2000rpm known as the C6B.

 

ArcEurotrade got me the C6 components so I could add the conventional belt drive back into my C6B! Bit of a cheat really but it’s made my C6B very versatile.

 

I think the photos are in my albums on this site, if not I can soon do that.

 

Steve

[Gordon WParticipant @gordonw]

I did a similar sort of mod to my asian lathe. made a large pulley to fit over the existing big pulley on the spindle. My pulley came of an old lawnmower, and is ally but for low use work like mine can be made from plywood, don,t even need a V groove for the belt. You will of course need a longer belt and may have to move the tensioner. Also on mine have to run with the belt guard open, so can’t really recomend it. PS this is the first lathe I’ve ever had with a guard.

[Steve WithnellParticipant @stevewithnell34426]

 

 

Here you go – low speed the belt runs from the lay shaft pulley to the spindle and high speed is a belt direct from the motor shaft pulley to the spindle pulley.

 

This is the new pulley I made for the motor shaft. The grooved part was done with a 5/8 tap held in the toolpost, so really easy to get the grooves “right” (idea copyright John Stevenson). This is a good match to the spec of a Contitech Poly V belt. Mine has run for years now and it’s showing no signs of abuse at all.

 

The tensioner needed a mod to work with the new arrangement, but again simple stuff (you can see the slotted plate I made to re-mount the original tensioner wheel).

 

 The outcome of this effort is that I have a lathe which has good torque from 40 – 2500rpm,  instead of circa  150 – 2000rpm.

 

Steve

Edited By Steve Withnell on 04/09/2011 17:13:38

[Michael Cox 1Participant @michaelcox1]

Hi Pailo,

I added a layshaft to my minilathe to reduce the speed by a factor of about 2. More details are on my website:

http://mikesworkshop.weebly.com/speed-reducer.html

I hope this helps

Mike

[adyParticipant @ady]

A high torque system is a must IMO.

My own backgear was broken when I got the old girl and it took me months to make the gear to fix it.

Worth the effort though, it turned my lathe into a different animal, my hobby lathe was transformed into a pretty serious bit of kit.

 

So if you’re going to get serious about latheing you should figure out something for a decent reliable low gear/high torque system, I can assure you, you will have zero regrets.

[Mark P.Participant @markp]

Thanks for the replies chaps,that settles it then next project coming up fit a backgear!

 

Regards Pailo.

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