fin dies 1

[TomFinck]

Hello I am looking for a low budget way to punch some .375 holes in aluminum sheet say .026 with a collar to fit around .375 copper tube and then expand it. I want to build some heat transfer coils

 

[MikeHalloran]

Use a .375 punch with a slightly pointed end and a small radius where you would normally have a sharp edge.

Use a 7/16" die with it.



Mike Halloran
Pembroke Pines, FL, USA

 

[griffengm]

Use a pre-punched hole with Mike's suggestion to better control the evenness of the collar. If you do not prepunch, the collar will rip and tear instead of expanding evenly around the hole.

Griffy