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The Original

Since 2009 CM Welding has served the farming community, having sold thousands of RPR Concaves™ and combine parts all of which proudly Made In America. 

Call 765-258-4024

RPR Concaves™ ·  

 Stops Rotor Loss  ·

 More Capacity

Not Just Concaves BUT A Concave System!
The Original  
SINCE 2013




Restricted Flow Threshing  
(forces grain against grain threshing resulting in cleaner samples) 

Progressively Open  
(more grain into cleaning section and not out the back of combine) 

Round  Bar
(eliminates plugging while providing a more aggressive thresh) 

Stop Rotor Loss

Crop loss during harvest is a major concern for farmers.  Rotor loss has been a issue since the rotor combines had been introduced in 1978. Rotor loss is caused by not enough opening in the front section of the concaves to accept the amount of grain coming in.  The separator can't handle the amount of grain coming in therefore the grain goes out the back.  

Patented Notch Round Bar

As early as the 1950s combines have been equipped with round bar concaves, but our Patented 90 Degree notch shown here is what restricts the flow of the crop and provides maximium aggression and is used in all our RPR Concaves™. Contact us today to learn more.

More Capacity

With RPR Concaves™, the load is taken off the separator by getting more of the crop down in the augers up front before it gets to the separator eliminating  the overloading of the separating section. The RPR Concave System threshing bars are progressively open allowing  for 68% more grain through the concaves while also doing less damage to the crop.    

Serving Farmers Since 2009

Since 2009 CM Welding has been selling Disrupters and Rotor Bars for John Deere and Case IH combines. Then, in 2014, CM Welding introduced the RPR Concaves™ which were entirely designed to prevent grain loss and keep what you harvest. Estes XPR 2 Concaves.

Cleaner Grain Sample

Our patented 90 degree milled notched round bars used in RPR Concaves™ provide  more aggression than OEM round bars and force more grain-on-grain threshing resulting in a cleaner grain sample. Call us for a free consultation to see if RPR Concaves™ are a fit for you today!

3,000 Customers & Counting

We have customers from all over the world and more than likely there is someone near you running our products. Call us, we can get you connected to one of our many happy customers.


EST. 2009

The Original RPR®Concave System  
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