Archive for November, 2014

The History of Lubricants

Friday, November 28th, 2014

Imagine what a pat on the back that smart fellow received when he discovered that applying animal fat to the wheels of chariots made them run more easily. I’ll bet he earned a day off for that one!

We’ve come a long ways since those primitive discoveries of using lubricants. Kathryn Carnes, features editor over at The Society of Tribologists and Lubrication Engineers took a look at the most critical moments in tribology’s history (the study of interacting surfaces in relative motion – i.e. friction, lubrication, and wear).

I’d like to share a few with you on the subject of lubrication in this brief history lesson.

As you might think, evidence of lubricants being used begins in ancient Egypt.

Many illustrations were left by the Egyptians showing large objects and stones being pulled across flat ground, or wooden planks. This was possible when people would pour down liquids before the object, so as to lubricate the surface area. For many tasks, olive oil was the lubricant of choice.

It’s been documented that the Egyptians also used pitch, which is a solid form of petroleum, for mummification. There are also biblical accounts of pitch being used by Noah as he built the ark.

By the 1600s, settlers in Pennsylvania were witnessing the native people’s collection of crude oil that had found its way up to the Earth’s surface. It was collected and used as fuel and medicine.

“To this day (and likely for many years to come) the influence and scope of petroleum lubes is unparalleled”, noted Kathryn.

Theories on hydrodynamic lubrication popped up between 1883 and 1905, when research showed that adding a fluid film would separate the surfaces of machinery, preventing wear and reducing friction. The increased pressure forces the surfaces apart, creating what’s called hydrodynamic lift.

Thanks to this discovery, we have slider bearings and journal bearings, both heavily used in machinery and vehicles.

The quest for synthetic alternatives began in 1877, when French chemist Charles Friedel and American James Mason Crafts developed the first synthetic hydrocarbons. It wasn’t until 1929 though, that commercial development of synthetic hydrocarbons occurred, by the Standard Oil of Indiana.

During the 1930s and early 1940s in Germany, synthetic fuels, rubber, lubricants and waxes would emerge on the market.

For those cases where liquid lubrication would not suffice, interest in self-lubricating materials was strong in the 1940s. The most famous of these was the discovery of PTFE (or Teflon) by Dr. Roy J. Plunkett in 1938. He came to this discovery in the midst of testing tetrafluoroethylene as a refrigerant.

That brings us to the discovery and application of elastohydrodynamic lubrication (EHD). In EHD, pressures are high and lubricant viscosity rises, assisting in the formation of an effective film.

Understanding EHD has led to the development of rolling element bearings, an invention which has allowed us to operate machinery and vehicles at a wide variety of speeds and loads, with very low friction or wear.

I hope you’ve enjoyed this look at how things were done in the past, and how they’ve led us to where we are today. I can only imagine where we will be in ten more years, or one hundred.

Original article from The Society of Tribologists and Lubrication Engineers can be found here.

How-To Replace Snow Blower Bearings

Friday, November 21st, 2014

Hopefully, after reading our last post, you’ve decided to give your snow blower a good check-up. This is especially necessary for machines 5-7 years old, as that is generally when wear-and-tear and rust will start affecting ol’ trusty.

Following our previous post, How-To Replace Snow Blower Belts, today we will go over replacing the bearing within the snow blower. We’d recommend doing this if you are replacing the belts even if the bearing seems in good shape, if for no other reason than you’ve already taken the machine apart!

As previously mentioned, once you have removed the old belts from your snow blower, you’ll want to inspect the pulleys. If they wobble or spin easily, the bearings will need to be replaced.

Don’t worry, it won’t take long.

Step 1. Position the snow blower so that the pulley is face up and you can easily work on it. Then, remove the nuts holding the pulley in place. (Sometimes rust causes the pulley to stick, so you’ll want to gently rock it back and forth while pulling).

Step 2. Loosen the screws around the sides of the adapter in order to pull the adapter off. Again, rust may make this difficult. I’d recommend using some oil in this case, and it should come off pretty easily.

Step 3. Once the pulley is off, pull the Woodruff key out from the slot (or tap it out with a screwdriver and a hammer), and remove the bolts at its base in order to pull off the cover.

Step 4. Now you can see the bearing. To pull it out, you’ll want to clean the shaft thoroughly and apply some oil or WD40.

Tip: If you find it particularly difficult to get the bearing out by hand, try using a puller.

Step 5. Set the new bearing on the shaft and use a socket to lightly and evenly tap it into place. Be sure the bearing sticks up a few millimeters from being flush.

To finish, you’ll just need to add the cover, adapter, and pulley back on.

Step 6: Set the adapter so there is about a quarter inch of clearance from the bottom to the bearing. There should be about a quarter inch of the shaft showing at the top as well. Then, simply reapply the pulley and tighten the nuts.

Now ol’ trusty can be just that again.

How-To Replace Snow Blower Belts

Friday, November 14th, 2014

It’s that time of year again – cold, cold, cold, and snow. Before the stormy weather really gets going, it might be a good idea to give your snow blower a check-up. If you have owned your snow blower for more than 5 years, the belts likely need replacing.

Learn how to replace these belts on your own with the help of this how-to.

Tip: To ensure you get several seasons out of your new belts, buy genuine factory belts from the dealer or online. For this you’ll need your snow blower’s make and model number and the engine brand and model number.

Replacing Snow Blower Belts – 8 Simple Steps:

Step 1. Safety first. Disconnect the spark plug wire from the spark plug.

Step 2. Remove the belt cover.

Step 3. Disconnect the chute crank and deflector cable. Then, remove the bolts and split the frame away from the auger housing to access the belts.

(If you see cracks, cuts, fraying or splitting, it’s time to replace the belts.)

Step 4. Remove the old belts. Use a 12 in. extension bar, ratchet and socket to remove the upper belt guard. Then, empty the gas tank and tip the machine up so you can remove the bottom access plate. Slide each belt out, and note how the belts are routed. You will reverse this procedure to install the new belts.

Tip: Take pictures as a reference to make sure the new belts are routed the same way.

Step 5. Inspect the pulleys. If they spin or wobble easily, the bearings may need to be replaced. (This will be covered soon in a future post – stay tuned).

Step 6. Install the new belts. Reverse the process in step 4. Thread the new belts onto the pulleys. Once in place, make sure they aren’t rubbing against any parts of the snow blower.

Step 7. Reconnect the frame by reinstalling the bolts to hold the frame and auger housing together. Also reattach the chute crank and deflector cable.

Step 8. Reattach the belt cover and the spark plug.

Tip: Don’t forget to add fuel back into the gas tank. Also, it’s a good idea to keep spare belts on hand so that if one breaks, you can replace it immediately.

Now that your machine is in top shape, you’ll be ready to take on that first winter snowfall.

Tensioning V-Belts

Friday, November 7th, 2014

We’ve all been there. One after another, we see or hear about equipment failure or breakage right under our noses.

What is the cause?  If we’re not careful, it could be neglect.  Let’s not have that happen again – at least not to our v-belts. This article will be a valuable resource for you and your team when it comes to proper v-belt care. I am going to lay out for you how to properly re-tension your v-belts. And I’ll tell you why…

Do you want to prevent premature v-belt failure?

Take this precaution to ensure long and successful operation from your v-belts. Tensioning is the single most important factor necessary for continual satisfactory performance. Without it, you will see slippage and rapid wear and tear which could be costly.

The proper tension for operation is the lowest tension at which the belts won’t slip at peak load. An under-tensioned belt will slip and cause heating and cracking. An over-tensioned belt may cause stretching and reduce belt life.

For this project, you will need a tension measuring tool. There are several on the marketplace. If you need a recommendation for your specific application, let me know

First order of business is, of course, safety! Be certain to turn off power to the motor and follow lock out procedures.

In order to re-tension your v-belt, you must first measure strand deflection. To begin, measure the belt’s span in inches – the distance from the center of the first wheel to the center of the second. The formula for deflection is then this number divided by 64, or 1/64th per inch of span length.

Then place the tension checker at the center of the belt. If this is a single belt, you will need to lay a ruler from wheel to wheel for a reference.

Push the tensiometer down until the rubber part is level with the ruler. You will then need to use the tension charts for your belt to check your tension against recommended settings. Follow the chart from left to right for the belt you have in front of you. It is recommended to re-tension each belt.

Keep in mind that tension is always changing. In an ideal situation, re-tension should occur after 20 min, 24 hours and again after 48 hours for a new belt.

If this isn’t possible for your schedule, simply run the belt a few revolutions with your hand, which will help the belt wedge down in the groove of the sheave. This is called seeding.

Once properly seeded, you will notice a decrease in deflective force, which means you will need to re-tension the belt again. Each belt should be re-tensioned after 8 hours of use, or daily, for heavily used v-belts.