Benchtop Slip Roll

[BrooklynBravest]

Designed this, started the build on it today. So far only cut the side plates, 1/2” mild steel. (Because they fit the take up bearing mostly)

At the rate i start and follow through with projects it will probably be completed in 2024.

It’s only gonna fit 24” wide max, hopefully be able to roll 3/16.

Lower rollers will use oil impregnated bronze bushings. Pillow blocks don’t seem necessary and are gigantic for the application.

Designed it in fusion 360.

I was going to plasma cut the screw holes but decided against it in the name of accuracy.

[farmersammm]

If you're able, try to simulate a heavily loaded shaft using both types of bearings...........bronze, and ball bearings. You'll find the difference to be HUGE.

I have a large piece of equipment that's hand operated. I was forced to redesign it, when I found that steel bushings caused incredibly heavy resistance. Substituted deep groove ball bearings, and it was like night and day. It actually made an otherwise inoperable design into a really pleasant machine to operate.

[farmersammm]

A bushing supports a much larger area of a shaft, which translates to increased friction. A ball bearing is akin to a wheel on a rail car........very little area of surface contact. Less surface area, less energy required to do the same amount of work.

[BrooklynBravest]

A bushing supports a much larger area of a shaft, which translates to increased friction. A ball bearing is akin to a wheel on a rail car........very little area of surface contact. Less surface area, less energy required to do the same amount of work.

I was kind of hoping it wouldn't be an issue I didn't consider how much side loading it would have :/

I'll have to check my model and see if i can incorporate a 2 bolt pillow block.

[tapwelder]

Any calculation on the force the bolt and top bar will accept?

[SweetMK]

A bushing supports a much larger area of a shaft, which translates to increased friction. A ball bearing is akin to a wheel on a rail car........very little area of surface contact. Less surface area, less energy required to do the same amount of work.

Hmmmmmm,, it is really kinda opposite of that concept,,
a bushing has LOTS of surface area, so the force per square inch is low for a bushing, allowing lube to remain between the shaft, and bushing.

A bearing on the other hand has a tiny amount of surface area, the force on the shafts will cause the bearing roller to push right through the lube.

When the bearing pushes through the lube, metal on metal contact occurs, and galling is the result.

Bearings require higher speed of rotation, because the bearing uses the speed to maintain lube on the rollers.

Back in 1979, I built a rather large machine that pulled polyester fabric through a furnace, at a slow speed,,
The bearings looked enormous, compared to the force of the fabric, but the fabric was moving slow,,

After only a few days, the bearings started to fail (there were dozens of bearings) ,,,
THAT is when I learned about bearings requiring a minimum rotational speed, to stay lubricated.

I changed the machine to all bushings, and there were no more failures.

Also, a bushing can be designed from dissimilar metals for the shaft/bushing interface.
Even if contact occurs between the two metals, galling is far less likely to occur, as compared to two hardened pieces of steel coming into contact.

Bearing fail so easily due to slow or no motion, that some large machines have to maintain constant minimum speed rotation, simply to keep the bearings lubed.

So, for slow or no rotation, bushings operate MUCH longer,,

[Fab54]

Was that cut with a CNC plasma cutter?

[SweetMK]

Here is some info in galling,,

https://en.wikipedia.org/wiki/Galling

"Galling is adhesive wear that is caused by microscopic transfer of material between metallic surfaces, during transverse motion (sliding). It occurs frequently whenever metal surfaces are in contact, sliding against each other, especially with poor lubrication"

"Galling can occur even at relatively low loads and velocities, because it is the real energy-density in the system that induces a phase transition, which often leads to an increase in material transfer and higher friction."

[acourtjester]

I built one a few years back and use 1" pillow block bearings for the shafts, worked very well. Since I only wanted cylinder with out taper, I did not have the adjustable ends. I did roll and new hand wheel for it from 1" square 11 Ga. tube.

[BrooklynBravest]

I built one a few years back and use 1" pillow block bearings for the shafts, worked very well. Since I only wanted cylinder with out taper, I did not have the adjustable ends. I did roll and new hand wheel for it from 1" square 11 Ga. tube.

That is beefy!

Was that cut with a CNC plasma cutter?

It was yes

[N2 Welding]

Hmmmmmm,, it is really kinda opposite of that concept,,
a bushing has LOTS of surface area, so the force per square inch is low for a bushing, allowing lube to remain between the shaft, and bushing.

A bearing on the other hand has a tiny amount of surface area, the force on the shafts will cause the bearing roller to push right through the lube.

When the bearing pushes through the lube, metal on metal contact occurs, and galling is the result.

Bearings require higher speed of rotation, because the bearing uses the speed to maintain lube on the rollers.

Back in 1979, I built a rather large machine that pulled polyester fabric through a furnace, at a slow speed,,
The bearings looked enormous, compared to the force of the fabric, but the fabric was moving slow,,

After only a few days, the bearings started to fail (there were dozens of bearings) ,,,
THAT is when I learned about bearings requiring a minimum rotational speed, to stay lubricated.

I changed the machine to all bushings, and there were no more failures.

Also, a bushing can be designed from dissimilar metals for the shaft/bushing interface.
Even if contact occurs between the two metals, galling is far less likely to occur, as compared to two hardened pieces of steel coming into contact.

Bearing fail so easily due to slow or no motion, that some large machines have to maintain constant minimum speed rotation, simply to keep the bearings lubed.

So, for slow or no rotation, bushings operate MUCH longer,,

was this with ball or needle style bearings? I would think needle style will handle slower speeds and higher load rating but have not researched it. Longer flat round cylinders rolling vs a ball rolling on a very small surface. Hmm.

[M J D]

I would use bronze bushings with the largest size shaft as possible. If using a solid roll deflection won't be much of a problem. If using shaft in a tube, I would put rings on the shaft about a foot apart and plug weld them to the tube.

[SweetMK]

was this with ball or needle style bearings? I would think needle style will handle slower speeds and higher load rating but have not researched it. Longer flat round cylinders rolling vs a ball rolling on a very small surface. Hmm.

IIRC, they were either ball or roller, not needle.

I actually went to the bearing store that sold the bearings, the counter guys were VERY familiar with the problem.
They acted like they saw this type failure all the time.

Operating equipment slow was not the intention of a bearing.

[BrooklynBravest]

I would use bronze bushings with the largest size shaft as possible. If using a solid roll deflection won't be much of a problem. If using shaft in a tube, I would put rings on the shaft about a foot apart and plug weld them to the tube.

The rings was my plan, but like 6” apart.

[M J D]

The rings was my plan, but like 6” apart.

What size roll diameter and shaft diameter?

[BrooklynBravest]

What size roll diameter and shaft diameter?

3” probably on a 1” shaft

The take up bearing is 3/4 because 1” gets huge

[M J D]

3” probably on a 1” shaft

The take up bearing is 3/4 because 1” gets huge

Ok, maybe 1/8" material of decent width. I would guess 4-6" wide for 3/16". Mine is 3' wide. 3.5" rolls with 1.5" shaft. I've rolled 1/4" x4", 3/16" x8" or so. Full width 14 gauge. It takes quite a few runs thru it to get a small radius.

[BrooklynBravest]

Ok, maybe 1/8" material of decent width. I would guess 4-6" wide for 3/16". Mine is 3' wide. 3.5" rolls with 1.5" shaft. I've rolled 1/4" x4", 3/16" x8" or so. Full width 14 gauge. It takes quite a few runs thru it to get a small radius.

I’m really just looking to be able to make 1/8” rings. It’s unlikely i need to roll heavier.

[M J D]

You should be fine with narrow widths. One issue that you get with a " pyramid" style roller is a bit of slippage, especially when starting the roll. Also usually about 4-6" of waste stock at the ends.

[farmersammm]

IIRC, they were either ball or roller, not needle.

I actually went to the bearing store that sold the bearings, the counter guys were VERY familiar with the problem.
They acted like they saw this type failure all the time.

Operating equipment slow was not the intention of a bearing.

I seem to remember seeing a lot of tapered roller bearings on MFD tractor kingpins. FWD tractors take a lot of abuse, especially when they're carrying front end loaders. A slow application involving less than 360* rotation.

Quite a few beam trolleys have wheel assemblies that utilize ball bearings https://www.aceindustries.com/p-4035...m-trolley.aspx

Jib cranes utilize tapered roller bearings https://www.gorbel.com/docs/default-....pdf?sfvrsn=17 Quite a low rpm situation. In fact, there's not even a full revolution involved.

All slow speed applications.

I suppose it's a tradeoff. Decreased friction vs. longevity. I think in this day and age, where motors do the bulk of the work, we tend to forget that human powered machines require significantly greater adaptation to the weakness of the human body.

I can't imagine using tapered bearings on a roller project............huge amount of machining involved. But ball bearings are the next best option in the name of operator ease.

[N2 Welding]

IIRC, they were either ball or roller, not needle.

I actually went to the bearing store that sold the bearings, the counter guys were VERY familiar with the problem.
They acted like they saw this type failure all the time.

Operating equipment slow was not the intention of a bearing.

perhaps roller is what i meant. needle are very small.

[djd775]

On the bushing vs bearing debate, you need to consider that different principles are at play.

Bushings are the equivalent of sliding a big box across a floor.

Bearings are the equivalent of rolling that same box across the floor on dowels or rods.

Bushings have friction as a part of their design; in an ideal world, bearings would come very close to zero friction on the rolling elements.


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[M J D]

Bushings can take a tremendous load, all they need is a film of lubricant. Look at the forces on the steering of a semi tractor, grooved bushings with a pin.

[12V71]

Bushings can take a tremendous load, all they need is a film of lubricant. Look at the forces on the steering of a semi tractor, grooved bushings with a pin.

Yep, that's why they use bushings vs roller bearings in high pressure hydraulic gear pumps.

[farmersammm]

On the bushing vs bearing debate, you need to consider that different principles are at play.

Bushings are the equivalent of sliding a big box across a floor.

Bearings are the equivalent of rolling that same box across the floor on dowels or rods.

Bushings have friction as a part of their design; in an ideal world, bearings would come very close to zero friction on the rolling elements.


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Absolutely.

It's an apples vs. oranges thing. I'm talking about reducing operator effort, others are talking about load capacity.

Nobody ever listens to me, which is ok Perhaps, coming from a "valid" source, it's more palatable https://www.bearingtips.com/bearing-...basics-primer/

Another consideration, not mentioned yet................................shaft wear.

A bronze bushing will eventually eat a shaft. A needle bearing will also eventually eat a shaft. Even a pressure lubed babbitt bearing eventually ruins a shaft when it wears (gas/diesel crankshaft bearings). You can bank on shaft wear with any bushing.

Roller, and ball, bearings operate in a contained system. Rolling elements caged inside an inner and outer race. The shaft never comes into play (unless there's a catastrophic failure, and the inner race spins on the shaft).