boring blind Merc blocks oversize

[Motion Machine]

Hello. First post here and if this violates any rules, let me know and I'll correct it. I own an automotive machine shop and do my block boring on a 4 axis CNC machine. I've made fixtures for blind Merc blocks and will link a Youtube video here showing the process. Most shops have a hard time with Mercs but this setup makes is extremely accurate and my Sunnen diamond hone has no problem honing a blind hole. I also can do any V outboard, which is done using the 4th axis. My contact info is on the video description.

https://www.youtube.com/watch?v=2LK6UuwzVsA

 

[fastjeff]

Where are you located? What do you charge for set up and per hole?

Jeff

 

[faztbullet]

I like to "cut" my bores to size and finish hone to spec...never liked hone to size boring as if stones are not off set they never reach bottom of the bore. The holder hits the combustion area.

 

[Motion Machine]

Where are you located? What do you charge for set up and per hole?

Jeff

Hi Jeff. I am in Danville VA, on the VA/NC border. For Mercs I charge $250 for a 2 cyl, $300 for a 3 cyl and $375 for a 4 cyl plus $20 final cleaning.

 

[flyingscott]

Maybe I am lucky because I live near Fon du Lac, Wi, But I see anywhere from $50-$100 a hole.

 

[Motion Machine]

I like to "cut" my bores to size and finish hone to spec...never liked hone to size boring as if stones are not off set they never reach bottom of the bore. The holder hits the combustion area.

I think you might be confused by the video. I did not show the actual boring process, this video shows the probing to find the bore centers. I bore to within .003" of finish size, chamfer the ports, then diamond hone to finish size and check results with a profilometer. The beauty of a purpose built diamond hone like the SV10 is that you no longer get out of round or taper, as with the style hone you describe. Diamonds do not need an overstroke to maintain a straight bore, this is why they are the only way to hone blind cylinders. I'll post a video of a similar fixture that I made for blind Harley cylinders. It shows the same boring tool that I use on outboard blocks..

https://www.youtube.com/watch?v=cDfueUhbGqs&t=30s

 

[Auto Marine Machine Shop]

AutoMarineDelMarVa.com
Auto Marine Engine Machine
Trappe MD
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