The Ford Barn

JoeCB · 09-12-2019, 01:35 PM

An interesting side issue that came out of the recent "babbit tolerance" discussion was the Ford process for finishing cylinder bores. Being a engine manufacturing guy I found it unusual that the Ford process for cyl bores as described in TerryButz post #23 Ref Ford Drwg, A-6015 called out "Ream 3.873 - 3.874 then Rolled to 3.875 - 3.876" . No mention of boreing or honing. The video posted by Railcarmover post # 32 of the Ford V8 process shows reaming and what looks like a roller burnishing process, again no Honing is shown.
Roller burnishing renders a smooth finish to metal surfaces, no pronounced profile as with the now common hone cross hatch pattern. So what is the deal here??
I talked to a friend that was a long time Ford engine development engineer ( one of the benefits of living near Dearborn) and he said that the now common X hatch hone principle was a late development from the post war era that came into play with the introduction of hard thin piston rings. Back in earlier times rings were soft cast iron and broke in with out the need for the X hatch profile surface.
This I thought was an interesting bit of engine development history. It would be interesting to learn just when Ford changer the process and introduced honing on cylinder bores.

Joe B

09-12-2019, 01:35 PM	#1
JoeCB Senior Member Join Date: Nov 2018 Location: Farmington MI Posts: 285	To X-hatch ot not to X-hatch? An interesting side issue that came out of the recent "babbit tolerance" discussion was the Ford process for finishing cylinder bores. Being a engine manufacturing guy I found it unusual that the Ford process for cyl bores as described in TerryButz post #23 Ref Ford Drwg, A-6015 called out "Ream 3.873 - 3.874 then Rolled to 3.875 - 3.876" . No mention of boreing or honing. The video posted by Railcarmover post # 32 of the Ford V8 process shows reaming and what looks like a roller burnishing process, again no Honing is shown. Roller burnishing renders a smooth finish to metal surfaces, no pronounced profile as with the now common hone cross hatch pattern. So what is the deal here?? I talked to a friend that was a long time Ford engine development engineer ( one of the benefits of living near Dearborn) and he said that the now common X hatch hone principle was a late development from the post war era that came into play with the introduction of hard thin piston rings. Back in earlier times rings were soft cast iron and broke in with out the need for the X hatch profile surface. This I thought was an interesting bit of engine development history. It would be interesting to learn just when Ford changer the process and introduced honing on cylinder bores. Joe B