Re-Crowning Of Top Ram


This Issue Comes To Light When Shimming Of The Top Mounted Die Is Required To Produce The Desired Quality Of Bend Needed. It Is Customary To Utilize The Center Of The Press Brake To Achieve The Majority Of Work Activity. This Wears Away The Factory Positive Crown And SET Begins To Overtake The Ram (And Bed Sometimes) Inverting The Original Crown To A Negative Crown Condition. This Is When Shimming Of The Upper (And Possibly Lower) Die Is REQUIRED To Achieve A Straight Line Bend.

There are Two Schools Of Thought(s) Regarding The CROWN (Replacement) Needed In The Top Ram Of a Press Brake. First The Popular Version Is To Have It Milled Removing Material From The Ends To Re – Establish The Center Based Crown Of The Top Ram.

This May REQUIRE REMOVING AS MUCH as 3/8 Of An Inch OR MORE Of Material From The Ends Of The Ram To Achieve A NEW RE-Established Crown. If This Process Has Been Done Before, The Press Brake May NOT Have The Material For Another Milling Job.

To Do A SELF Test, To Determine The Amount Of Negative Crown In The Upper Ram Of The Press Brake == Use A Nylon Fishing Line 10# Test Preferably Colored (green) For Visibility. Stretch The Line From End To End Of The Upper Ram Line Touching The Ends Of The Ram And Use A Flashlight To Visibility Inspect The Amount Of Distance From The Negative Ram Crown To The Fishing Line PLUS The Additional Amount For The NEW Crown. This IS The Amount Of Material That Is Missing. The Top Of The Ram Has Actually Stretched A Little And The Negative Crown Missing Material Has Actually Been COMPRESSED, And Some Worn Away. Now That You Have Done The Test, This Why Shimming Is Needed. Even a BRAND NEW Machine On The First HEAVY MAX LOAD Bend With A Short Die Can Receive Set, (Negative Crown) That Is Detectable With Fishing Line.

RAKO’s Recommendation Is To Remove The Top Ram, Turn It Upside Down And Build It Up With Weld Material And Re – Establish A NEW Crown In The Top Ram And Give The Machine Another New Life. Please Contact RAKO 316-214-8100 For MORE Details.



The Recrowning of the Top Ram Is Needed, When Shimming The Top Die No Longer
Works Well. Please Contact RAKO For Complete Details.
Roger A Knight
Cell 316 – 214 - 8100 cstz and TexT Pictures