Lubricating rollers for saw infeed/outfeed

[winchman]

I've been installing rollers on the infeed/outfeed arrangement our local steel supplier uses to cut metal to length. The twelve ten-inch long rollers are made from 1 1/2" schedule 40 pipe with a bushing on each end made from 1 5/8" round bar. The supporting shaft is made from 3/4" round bar. The bushings are one inch in length.

I wanted to drill a hole in each end of the shaft with a cross-drilled hole for lubricating the bushings, but they assured me they'd never get greased or oiled. I feel like I've got to come up with inexpensive, but long-lasting passive solution to keep some oil on the bushings.

The best idea I've come up with so far is to put several eight-inch pieces of fiber rope inside the rollers, and saturate them with 80/90 weight oil. I figure the rope will flop around as the rollers turn, and some of the oil transferred to the shaft will migrate into the bushings. Will that be worth the trouble? Any better ideas?

Here's the section I'm working on. There's another one like on the other side of the saw. Each section will have six rollers. The beam is 10x14, and it weighs 68 pounds per foot.





In addition to installing the rollers, I'm shortening the height of the support frames, adding adjustable feet, and adding a fence to keep small stock from slipping behind the uprights. I'm also going to build a cradle between the two pieces to support the saw.

Here's the clamping arrangement I used to set the rollers 1/4" above the top of the beam while welding the shaft supports in place.

[mattthemuppet]

Why not sealed ball bearings? Cost more but the service life should be longer. All the conveyors I worked on sorting veggies used that system.

[DR]

You can buy pre-made feed rolls with sealed ball bearings on the axles. Not dirt cheap, but neither is your time to make rolls.

[boslab]

Why not sealed ball bearings? Cost more but the service life should be longer. All the conveyors I worked on sorting veggies used that system.

More or less what I'd do, the last conveyor I used hydraulic lip seals outboard to prevent the dirt getting in, it's still in use fending off mill scale a couple of years later, the seals were the shaft seals you find on the outboard side of hydraulic Rams
Mark

[winchman]

I suggested both using sealed bearings and buying the rollers, but they wanted to use the pipe and round bar. The rollers work surprisingly well dry, but I'd really like to keep a little lube on them for the long term.

The shaft has a hole on one end for a hitch pin clip. The other end has a washer with two flats so the shaft itself doesn't turn in their supports. All the wear will be on the bushings and the shaft, and the shaft can be rotated half a turn to get some more life out of it. It's not that hard to make new ones, either.

So, is the oil-soaked rope worthwhile?

What about filling the roller part way with graphite or something similar?

[Abner]

First, who has a shop that nice(?) I don't consider myself envy prone but I'm making an exception.

I like your idea of oil and rope or old cotton socks perhaps. Would it work to put in an O ring? I have no idea of the wear it might get or the life span.

[Hal]

Try brass bushings that have oil in them. I can't remember what they are called.

Hal

[winchman]

The problem with putting bearings in the pipe is that it won't fit inside the spindle of the lathe (a 13" Cincinnati tray top), and the OD of the pipe isn't round enough to be able to use the steady rest. That also makes it difficult to install oilite bushings at this point.

The OD and surface of the 3/4" round bar isn't consistent enough to use an O-ring or oilite bushings.

I made the bushings with a slight taper on one end, and drove them into the pipe with a rubber mallet before welding them in place with several short beads around the ends. I had to grind a groove in the bushing to clear the weld bead in the pipe, so oil will probably leak out there.

[cameron]

The rope with oil sounds good to me. If you ran a bead all around the bushings to seal against leakage, you could fill the pipes with oil almost to the bottom of the shafts, and oil would only seep out when the rollers were actually turning. Probably not a big concern if the place is like the typical steel suppliers premises.

[Abner]

This is starting to sound like they are penny wise and pound foolish. I dislike situations where cost seems to be a determining factor in an industrial situation like that. I hope this turns out OK for you.

[boslab]

How about boring the tube ends for the bearing od, deep, like x2 bearing thickness, then grease pack followed by lip seal for same size as bearing od?
Mark

[BCRider]

For what you are suggesting I think that would work well. Just need a way to get the rope in and not burn when you weld the plugs into the end and then a way to get the oil into it. At least I'm assuming the plug/bushings will be welded in place. You'd place the rope sections in through the holes for the shafts before slipping then onto the shafts I'm guessing? Same for the oil? What about some time down the road for adding more oil?

[DR]

I suggested both using sealed bearings and buying the rollers, but they wanted to use the pipe and round bar. The rollers work surprisingly well dry, but I'd really like to keep a little lube on them for the long term.

The shaft has a hole on one end for a hitch pin clip. The other end has a washer with two flats so the shaft itself doesn't turn in their supports. All the wear will be on the bushings and the shaft, and the shaft can be rotated half a turn to get some more life out of it. It's not that hard to make new ones, either.

So, is the oil-soaked rope worthwhile?

What about filling the roller part way with graphite or something similar?

Hopefully you're getting time and material on this project.

Sometimes you have to lay out the relative costs/advantages to customers. Most of us in business face the deal with customers who insist on supplying or using poor quality existing material which usually is the worst and most expensive long term solution.

[Peter S]

Winchman,

I am sure you will make something that does the job well, but here are some other ideas anyway, it might help someone.

This frame was made about 20 years ago, but now retired. The power hacksaw was bolted to the flat frame in the centre area. It requires good welding skills, but once made it cannot be put out of alignment, because there are no adjustments and the whole frame is a rigid piece).

Not shown, but the whole frame was then bolted to the floor with adjustable feet, so the whole assembly could be leveled (so coolant doesn't run down the steel being cut). The adjustable feet also raised it off the floor so it could be cleaned underneath. Furthermore, it raised the power hacksaw to a better working height.

The roller bed is made so you can walk through it.

The rollers are 50mm nominal bore, heavy wall steel pipe (the cheap stuff used for water and air etc.). The approximate dimensions of the pipe are OD 60mm, ID 51. The pipe is then bored out to 52mm at each end.

Bearings are then fitted, these are based on the self-aligning range, but with parallel OD's. So you get the advantage of a set screw/grub screw locking sealed bearing, with snap ring to act as a shoulder and a bearing ID that is sized to slide down off-the-shelf 25mm bright mild steel.

Shaft ends are faced and tapped for mounting bolts, not sure if they are tapped off-centre so the shaft can be adjusted eccentrically for fine tuning of roller heights (in case of welding distortion). Edit, just checked, no adjustment possible at rollers. The flat steel tabs locating the rollers are drilled 25mm so the shaft goes right through. This means the rollers can take more shock loads as steel is dumped on them. The bolt in the end face simply holds a fender washer in place to retain the shaft. Not really required because the shaft cannot move either way once the bearing set screws are tightened. I would make the shafts a bit longer and not tap the ends.

If fine adjustment was necessary, you could drill the flat steel upright tabs 20mm and turn a 2.5mm offset on the end of the shafts. But some means of shaft adjustment and locking then required.

Actually, the present shafts are just tapped one end, the other end has a flat steel tab welded on, I am not sure why.







The bearings shown in the last photo are actually 20mm shaft with 47mm OD.

The bearing numbers used for the rollers above are:

25mm shaft: NTN UCS 205-25 D1NR or NSK UCS 205 LD1NR.

nb, suffix D1 means regreasable,, but it doesn't matter for this application.
suffix NR gives you the snap ring.
Prefix 'S' means parallel OD.

This type of bearing is available with inch bores too, e.g. NTN UCS 205-7/8-15/16-1 DINR all have 52mm OD. UCS 204-3/4 D1NR has a 47mm OD.

There are plenty of applications for these bearings, for example an idler sprocket that can be set in the correct position on a shaft then locked in place.

BTW, I have also seen lighter duty roller beds for cold saws using ordinary sealed ball bearings fitted to steel tubes, they are just slid onto a shaft without any means of locking the bearing to the shaft. This is because there is nothing causing the inner race to spin. For example a cheap sealed 6004 bearing has a 20mm ID and 42mm OD and fits nicely into machined 40mm nom. bore heavy wall tube (tube OD approx. 48mm, ID approx 40mm). Tap the shaft ends say M10 for mounting (easier to accurately drill 10mm holes than 20mm).

[winchman]

Here's the section I've finished.





And this is the other half after the supports have been removed so I can shorten them several inches.



They told me yesterday they want a slide-out five-foot extension on the end of this section to support long pieces of flimsy stock. More fun.