Anyone here use a notched V-Belt on their lathe?

Thinking about picking up one of those notched V belts that have lower bending resistance, seems like that will translate to slightly more power available for turning on my 9A. The main issue I can think of is that it will also mean less surface area in contact with the large countershaft pulley, but i'm not sure if that will be a problem since it's so much larger than the small one, it has to have more surface contact.

Anyone have any thoughts one way or the other?

I've always thought the point of notches was to allow the belt to conform more closely to small radius sheaves. That's where they tend to slip first. Large radii, slow belt speeds? Ne'mind the notches.

Yeah, the pulley on the motor is only 2", so a pretty tight curve

Domodude17 said:

Yeah, the pulley on the motor is only 2", so a pretty tight curve

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Useless tight. Notched belt will help, but it is still in the same category as spending years of yer life at pissing up a rope. Two fixes:

- Convert that stage to Poly-Vee or Micro-vee "serpentine" multi-groove. Those do tighter curves better. Automotive parts-bin or salvage can find you the pulleys and a spring idler.

- Go up to 3 /12" or 4", still legacy Vee. Spring for two roller-bearing pillow blocks, a shaft, pulleys .. and have added another countershaft stage to get the RPM where yah need it to be.

Even in "Z" section belting, let alone "A", a 2" pulley isn't good for much but selling more belts off the back of f**king them up faster.

Would a toothed timing belt work on the large flat countershaft pulley? Seems like that would be even better than a serpentine belt

Domodude17 said:

Would a toothed timing belt work on the large flat countershaft pulley? Seems like that would be even better than a serpentine belt

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LOL!

Oh, yes, but...

I have a combo milling machine (USMT "Quartet") with so damned many of the early-day "Gilmer" trapezoidal "tooth" pattern that USMT must have been getting co-op advertising to showcase the damned belting!



IF.. you can find surplus wheels on the cheap.

Problem is that they aren't pulleys.

They are actually a form of "gear" and must be made to the same sort of rigid pitch-line / tooth-count and expensive tolerances. Read "not easy to DIY". Not even with a mill or shaper, the correct profile of form cutters, and a good indexer or Dividing Head. Too easy to get WRONG.

By contrast, the circumferential grooves for a Poly-vee or Micro-Vee are easy lathe work, and don't ALWAYS even have to exist. Lots of SB's are using them with no grooves on unmodified flat-belt pulleys. We do that on 10EE for the surfacing feed belt as well in place of flat belt. Tips of the tiny Vees's sorta mush-down, grip is great. Two-inch, I'd cut the gooves nad to a good fit. or jsut find a ready-made pulley.

It's only a SB nine. Not a 100 HP motor.

Domodude17 said:

Would a toothed timing belt work on the large flat countershaft pulley? Seems like that would be even better than a serpentine belt

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They aren't running the groove side toward pulley with serpentine belts.

They turn belt inside out, so that flat side of belt is against pulley, or the normal up side is down.

But maybe you know that, and are thinking the ribbed side of timing belt would work like an upside down version of this thread topic of notched vee belt.

texasgunsmith said:

They aren't running the groove side toward pulley with serpentine belts.

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Yes, we most assuredly are!

They transmit more power that way, even with no matching grooves.

Think of it as a flat belt (barefoot) with squishy grooves (rubber boots!). The deck doen't have mating grooves nor is a highway ribbed to match snow tires.

The back side of any of legacy vee, Poly/Micro Vee, or synchronous belt is able to manage an IDLER, but is not meant to transmit any significant power.

Wrong materials and construction for it.

Double-angle Vee and double-sided synchronous etc. are built for that.

thermite said:

Yes, we most assuredly are!

They transmit more power that way, even with no matching grooves.

Think of it as a flat belt (barefoot) with squishy grooves (rubber boots!). The deck doen't have mating grooves nor is a highway ribbed to match snow tires.

The back side of any of legacy vee, Poly/Micro Vee, or synchronous belt is able to manage an IDLER, but is not meant to transmit any significant power.

Wrong materials and construction for it.

Double-angle Vee and double-sided synchronous etc. are built for that.

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Really ? I'm sure I have seen them run upside down on lathes.

I can't 100% remember, but I seem to recall someone running it right side up, and over time had wore some grooves in their flat pulley, from the grooves in belt riding in the same location continuous. But I truly don't recall the details.

On engines, you have crank, fan, alternator, and tensioner at minimum. So contact area for each pulley is smaller. Assuming a lathe with just two pulleys, that would be close to 75% contact area per pulley. I would guess that's enough grip, but I have not personally gone this route on anything.

On grooved side, the grooves do matter though. Grooves on grooved pulleys will wear to the extent, that even with a new belt, the belt/pulley will squeal, and need replacement pully. And/or the grooves on pulley become sharp, and belt sinks into it, getting sliced along each groove.

texasgunsmith said:

Really ? I'm sure I have seen them run upside down on lathes.

I can't 100% remember, but I seem to recall someone running it right side up, and over time had wore some grooves in their flat pulley, from the grooves in belt riding in the same location continuous. But I truly don't recall the details.

On engines, you have crank, fan, alternator, and tensioner at minimum. So contact area for each pulley is smaller. Assuming a lathe with just two pulleys, that would be close to 75% contact area per pulley. I would guess that's enough grip, but I have not personally gone this route on anything.

On grooved side, the grooves do matter though. Grooves on grooved pulleys will wear to the extent, that even with a new belt, the belt/pulley will squeal, and need replacement pully. And/or the grooves on pulley become sharp, and belt sinks into it, getting sliced along each groove.

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South Benders do it both ways. Some also cut the belts and lace them, Some cut the belts and glue them.

I don't understand any of that.

1959-60, we were taught to skive a taper into the LEATHER flat belt and glue it with ignorant hide glue.

It was never a problem in need of any other solution but the OEM leather belt one. Some folks just have a compulsion to outsmart themselves by making easy things harder.

SB's have typically 3/4 HP or less, max, use only a fraction of it.

The serpentines used are typically rated 5 HP or better in long-serving and severe underhood environment automotive use. Rib-count thing. They only MAKE one width, over a meter wide.

The rest is done by a "slitter" making-up various widths out of the raw "master" band stock at each given hoop diameter/length.

One popular fine-grove family is rated about .41 HP per rib. More power = more rib-count = wider belt. Published information. That simple.

I can't imagine an SB's miniscule loading wearing one of proper width out before the lathe itself is worn clear to flinders. Even the OEM leather belts last for long years.

SB's are light lathes. VERY light.

5 HP air compressor, (Dayton // El Cheapo)? Those I HAVE seen wear-out serpentine belts and shiney-wood pulleys.

CI - or the steel ones automotive uses? Not so much and not so fast.

If ANY of them are wearing sharpish? That's from slip. annnnnd ..

We are back to the door we came in through.

The pulley is too small in diameter for the loading. Or not WIDE enough for the loading and diameter.

I've run those belts on a 9" lathe with no trouble. 2" dia motor pulley sounds a bit small but I seriously doubt you'd have any issues with power transmission with the segmented belt given how poor the flat belt system is for transmitting torque. Those South Bend guys were pretty smart though because the drive system won't transmit enough torque to hurt anything.

Dobermann said:

Those South Bend guys were pretty smart though because the drive system won't transmit enough torque to hurt anything.

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LOL! One of my late parents' favorite stories, first weeks married.

Dad, a fair cook, Mum, never having learnt to even boil water, had burned the eggs, got her Irish up when Dad tried to explain, heaved the coffeepot at him.

He jouked. It missed. Hit the wall. Hardly any colour to it.

"Thanks for throwing the coffee. It was too weak to hurt anything."

He WAS wise enough to already have his arms around her before the cast iron Griswold skillet followed it, though!

You'd have to know sassy wimmin'?

I'm guessing you're referring to using them on a flat-belt lathe?

Don't forget that SB had them with V-belt pulleys as well (my 16 speed 9A).
And yes- it will use every bit of the power from the 3/4 hp, 3-phase motor driving them.

I can stall the motor, and not slip the belts if I push the DOC too far.

I run a serpentine on my Logan right-side-up with no problem. I used to run a Fenner belt on the V/flat pulleys as you see in the photos but I think I changed it to a regular V-belt with the notches. The Fenner worked fine but I just wasn't comfortable with the tabs running on the flat pulley. IMO, the notches are the way to go. Use high quality belts for smoothest operation.
Logan model 211 lathe

IMO you dont want any type of cogged belt running on flat pulleys...might just be a principle thing and not make much difference in practice.

as for the poly v belts i always ran them with the grooved side against the pulley.
never understood why anyone would turn them inside out.

iwananew10K said:

IMO you dont want any type of cogged belt running on flat pulleys...might just be a principle thing and not make much difference in practice.

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You got that shot right. The surface of the toothed side is slick - "armored" against friction, even.

As with gears, it is meant to "engage and disengage" not friction-grab.