V-belt adjustment

[Singermania]

Like I said, you were bound to get some serious technical advice.  Trying to work out deflection from a given centre force is a bit serious, not withstanding that all A or V belts are not created equal and will flex or stretch a bit differently.    Really its simple enough, if its too loose it will slip, if its too tight it will bind up the machine and the belt will practically ping if you flick it with your finger.   Its a wet rainy day here and am catching up on some leisure time, hope everyone out there is also having a good Sunday.

[Art]

Hotter than the hinges on the door to hell here, but finally some rain to cool it off a bit.  Isn't it supposed to be winter down your way, it should be raining or snowing.

Art

[Wizcrafts]

I spray belt no-slip from auto parts stores on my v-belts on my Cowboy CB4500. That way I don't have to overstress the belts and bearings.

[Evo160K]

Thank you good people one and all.

[Singermania]

You're right Art, its Winter here, but up in Queensland its usually shorts and t shirts all year round, so long pants and socks is cold for us..

[Gregspitz]

just after reading this thread..I started sewing with my roller foot machine with the speed reducer in thicker material and the belt slipped!  quick slight tightening AND used some belt dressing I had from the auto parts store that I spread evenly on both belts with a small sponge...and it seems to be working better than ever!

thanks everybody AGAIN!!!!!!!

have a great day

[GPaudler]

Though it's often cited and is about as scientific as most people care or need to get, a simple measurement of V-belt deflection really isn't very meaningful. 

It's not important but understanding the mechanics might help someone if slippage should become a problem. It's helpful to think of it in terms of friction due to surface contact. A skinny belt on small wheels has much less surface contact than a fatter belt on big wheels so will need less tension to resist slipping. The material and finish of the wheels makes a difference as do the material, age and condition of the belt.

Wiz's suggestion to use belt dressing available from auto parts stores in spray cans or squeeze tubes is good, especially for older, oxidized belts, for achieving maximum friction.

So sure, try adjusting for 1/2" of deflection (though how hard are you pushing?) and if it doesn't slip, then you're good. If it still slips, make sure that your V-grooves and belts are clean and rust-free and treat your belts to some dressing.

[graywolf]

"How hard are you pressing?"

Should be just enough to take up the slack. That is all you are interested in.

Belt dressing, auto transmission fluid works very well. Don't soak, just dampen.

Once again, I am writing from the viewpoint of a electro/mechanical engineering technician with with about 60 years experience. Sewing machine repair, I am just a hobbyist.

[Evo160K]

You people are awesome.  Thank you.