

KR521 Envelope Inserting System
Summary
Originally designed for the 9” x 12” inserter market, the KR521 is flexible enough to handle most other sizes as well. From open end flaps, to long side flaps, even overnight letter envelopes, this engineering marvel is built to perform.
Using Kirk-Rudy’s highly reliable KR324 Shuttle Feeders to deliver inserts to the lugged transport belt, the KR521 delivers a consistent, smooth, and safe work flow. The envelope flap opening section utilizes a pinch roller/plow assembly combined with a compressed air blast to positively open every flap.
Like all Kirk-Rudy equipment, the KR521 is modular in design and is compatible with other Kirk-Rudy equipment such as turn-over units, labelers, inkjet printers, sorters, stackers and conveyors.
Features
- Heavy-duty, built for production environments
- Add up to 9 inserting stations
- Semi-automatic lubricating system
- Handles up to 10” x 13” envelopes, down to #10 size
OUR PROCESS
Our Easy 5 Steps
Insource Corp was founded on a guiding principle that motivates our team and priorities daily: the customer and their objectives are paramount. We know and believe that if this simple philosophy is adhered to, then all else will align.

STEP 1
DISCOVERY
Our Solutions Team will walk through a discovery session with your team

STEP 2
ANALYZE AND IDENTIFY
We analyze and identify the best solution(s) to align with your needs and goals

STEP 3
DEMONSTRATION AND PROPOSAL
We introduce and review the solution(s) with your specific application, demonstrating opportunities for success

STEP 4
INSTALLATION AND SERVICE
Our factory trained service team completes installation and training

STEP 5
PARTNERSHIP FULFILLMENT
We maintain our commitment to your success with local service, training, parts and consumables–all a phone call away