Gear Coupling Repair & Rebuild - What You Need to Know

Even with lubrication, gear couplings involve tooth-to-tooth (generally metal-on-metal) contact that gradually will wear down the gear teeth. This wearing phenomenon is not unique to gear couplings... and in gearing applications such as gear boxes, who industries have been built around gear repair, rebuild, and replacement.

As such, it would be natural to wonder if worn gear couplings could be repaired or rebuilt... and, if so, what exactly that looks like.

(Being a leading gear coupling manufacturer, this is certainly a question that we are presented with on a regular basis... and are very well prepared to answer.)

To quickly cut to the chase and answer this question as briefly as possible... Yes. Gear coupling components from a given manufacturer generally have interchangeable parts that can be replaced on an as-needed basis. Seals and gaskets can be replaced. Lubrication can be changed out, and, if necessary gear coupling sleeves and hubs can be interchanged. 

Flanged "F Type" Gear Coupling

Elaborating just a bit... it is important to note that if a gear coupling hub or sleeve is changed out (giving it new gear teeth), the corresponding hub or sleeve should also be changed out (so as not to have worn teeth engaging with new "fresh teeth"). This logic means that it is acceptable to replace on half of an "F Type" flanged style gear coupling (replacing both the hub and sleeve on one side), while leaving the other side as the original. 

Bonus Tip #1: Because "C Type" continuous sleeve gear couplings make use of a common sleeve that would be new to both hubs, these type couplings are generally not suited to be changed out as a "half couplings".

Bonus Tip #2: If and when changing out a flanged "F Type" gear coupling half coupling (with new hub and sleeve on one side), it is critical that you ensure the bolt pattern matches up to the bolt pattern of the original manufacturer. As a standard, Lovejoy, and many other North American manufacturers adhere to a common bolt pattern standard that holds true through generally a size 9 gear coupling (AGMA 9008-B00: Flexible Couplings -- Gear Type -- Flange Dimensions, Inch Series).

Continuous "C Type" Gear Coupling

Bonus Tip #3: If mixing and matching flanged "F Type" gear coupling halves between two different manufacturers, it is also important to ensure that both manufacturers' products meet the required application's bore and torque requirements. (Common AGMA flange bolt patterns does not mean equivalent torque and bore ratings, and should always be checked.)

Bonus Tip #4: Prior to replacing any gear coupling, it is always worthwhile to inspect and understand how and why the coupling is wearing. Gear couplings often provide signature wearing patterns that can help alert you to potential issues (i.e. - excessive misalignment) that should be addressed to prior to re-starting a system. (The following article provides a number of great photos to help analysis gear coupling wear: Gear Coupling Tutorial - Part V: Failure Analysis (with photos).)

Final Tip: We (Lovejoy) have been selling our legendary Sier-Bath gear couplings for decades, and recently released our cutting edge HercuFlex gear coupling product line. Our engineers are world class, and we know the gear coupling marketplace and the solutions available down cold. Should you have any question or need regarding gear couplings (bolt patterns, interchanges, application recommendations, etc.)... please do not hesitate to reach out to us. We take tremendous pride in being a solutions oriented organization, and look forward to helping you and your business in the very near future.

How to Get a Replacement Coupling Fast

When the line goes down and production stops, time is money. Whatever broke must be root caused quickly, and a replacement coupling must be secured as quickly as possible. Specific to couplings, Lovejoy's application engineering department is acutely aware of how important speed of service is in such situations, and has developed a Quick Ship program exclusively to help take care of breakdown customers as soon as possible.

This program is available for jaw coupling hubs and spiders (L, C, & H types), curved jaw coupling hubs and spiders, s-flex sleeve coupling hubs and flanges, LF torsional hubs and flanges, universal joints, NEMA pump / motor mounts, gear couplings, and grid couplings. (An exact PDF document outlining the program can be found here, and if you don't see what you are looking for... please still feel free to call and we will let you know the best we can do. We carry an enormous amount of stock, so the part could be either on the shelf or easily finished to your needed dimensions.)  

 

So what exactly does the Quick Ship program look like, and how will it ensure I receive my coupling quickly? 

Lovejoy actively embraces a manufacturing concept called Quick Response Manufacturing (QRM), and championed by the University of Wisconsin's Center for Quick Response Manufacturing, which focused exclusively on optimized processes, systems, and procedures for manufacturing companies with a high mix of products, but with relatively low quantities. (This concept applies very well for Lovejoy, and its tremendous breadth of coupling product and the near infinite combination of bore & keyway combinations that exist for each.) 

One core principle of QRM is the concept of elasticity of demand, which basically states that for a factory with high mix to run effectively... there must be an ability to absorb peak demands without wreaking havoc. (For a more complete overview of QRM, check out either the University of Wisconsin link posted above or this Wikipedia article.) A common analogy or example to demonstrate this principle is an interstate during rush hour. Orders do not always (or often) come in predictably, so a company must be able to flex as peak loads hit without creating gridlock. 

Lovejoy provides customers, and specifically Quick Ship customers, elasticity of demand by having three dedicated finishing work cells set aside for the unexpected Quick Ship. Customer service owns these work cells, and the shop floor and Lovejoy's scheduling department do not schedule these cells.

When a call from a distributor comes in, Lovejoy's customer service team will quickly qualify the Quick Ship (ensuring it meets the criteria of the program inclusive of limited quantity and raw parts on hand). Once qualified, the Quick Ship order is printed directly to the Quick Ship cell. Upon completion, Quick Ship orders are immediately taken down and put on a bright red cart in front of Lovejoy's shipping/distribution department to ensure the order is promptly boxed and queued for carrier pickup. 

 

Quick Ship sounds great, but what are my next steps?

This may sound obvious, but the first think you want to do is to understand what went wrong with the original application. Did the original coupling wear out due to normal wear, or was something more troublesome going on (misalignment, peak torques, chemical exposure, undersized coupling, etc.). If you have no idea, please feel free to give us a call or read some more articles on this blog to better educate yourself... as we really don't want to see you repeat or not correct a mistake or issue that may exist with your given application.

Once you've got an idea of what went wrong and know the type of coupling you need fast, you will want to reach out to a distributor you trust and ask them you've got a breakdown situation an need a Lovejoy Quick Ship. (To find a distributor near you, please visit this page... and, while an authorized Lovejoy distributor should immediately understand and appreciate what a Lovejoy Quick Ship... should there be any question, please feel free to forward them this link.)

Note: Quick Ship orders need to be placed over the phone by the distributor to Lovejoy. As soon as your trusted distributor does this, they will be able to give you the promised lead time and cost for the coupling or product in question. At this point, your order will already be in route or in the hands of a Lovejoy operator ready to fight the good fight to get you up and running in the shortest possible time period.

 

And what if it wasn't the coupling that failed?  

Lovejoy is, at its heart and soul, a coupling company... and, while we wish we could help you with your bearing, pump, motor, etc. failure... there is a much better resource to lean on: your trusted mechanical power transmission distributor. These guys (and ladies) know the industry inside and out, and they know which manufacturers they can trust and lean on to get a product out fast. If you don't yet have a relationship with a linchpin distributor you trust, we recommend you start by searching for one here (which even allows you to search by zip code for those of you living in the United States or Canada). 

 

As a final word of caution...

To reference the Aesop's famous fable of The Boy Who Cried Wolf, if the replacement part need isn't an emergency, please be truthful about your time requirements when working with your trusted distributor partner. While not always the case, time can and does often mean more money (even if it is only in the expedited shipping fees) and does take a bit more work on the distributors part. Almost always rush orders require automated processes (placing and managing orders with manufacturers online) being turned into manual ones (phone orders and more manual tracking). Please be respectful of your distributor's time, your own wallet (or your company's wallet), and allow the emergency lane to remain open to those in most urgent need.