I was looking some specs about a shredder , and i found this guy in a Polish forum , he have some videos , and some good ideas , for the first time i see an homemade machine to remove the vein .
https://www.youtube.com/channel/UC3ZBXIYp4nJA3lfxR6aBxXQ/videos
https://www.youtube.com/channel/UC3ZBXIYp4nJA3lfxR6aBxXQ/videos