A couple months ago we got a request from McGovern Metals in Roseburg, Oregon to fix their Shear machine attachment, which cuts large pieces of metal in their scrap yard.
The main problem was that the upper shear had cracked, so we lanced out the shaft pin in order to repair the crack. Turns out, the shear had cracked all the way through! So we excavated the cracked area to get a full penetration weld. Because of this new weld, the hole that the pin goes through was no longer perfectly round or the correct size, so we used a portable line boring tool made by Climax to machine out the hole and get it to the right shape and size.
Because we lanced out and destroyed the original shaft pin, we had to machine a new one. Before doing that, though, we cut off a quarter inch sliver of the pin so that we could send it up to Schnitzer Steel in Eugene to get tested to see what kind of material the original shaft pin was made out of. It’s critical to get all these pieces right and make sure we’re using the right materials since each job has its own specifications and tolerances needed.
Once the shear was repaired and the new shaft pin was machined, we were ready to put it all back together! Easier said than done…
Step 1 - submerge the pin in a container filled with liquid nitrogen (which is about negative 300 degrees) to make it shrink
Step 2 - while that pin is boiling (yes, boiling) in the liquid nitrogen, heat up the bore that was cracked and repaired to make the hole larger
Step 3 - when the pin stops boiling and the bore is nice and toasty, slip the pin in…and DONE!
This Shear is like huge scissors, so precision and accuracy were very important! Being off even 0.010” (ten one-thousandth of an inch) is a problem because the shear “blades” need to be close to work right. But our team of machinists, welders, and fabricators did an outstanding job! (as always! 😉)
We hope you enjoy seeing a visual of this process!
Негізгі бет Shear Repair Process
No video
Пікірлер