BB Exhaust jig 3D printed

shepherm

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So one of my exhaust studs on my Charger was broken and didn't have much luck with Kroil, welding, or left hand bits. So next I want to drill it out to see if I could re-tap the hole. I knew I wanted some type of jig to hold the bit straight and centered. Looking back I should have start with one of these before trying the left hand bit.

So I designed and printed a few different ones with the polit holes sized for a few end mills I hand. I started with a small end mill and worked up to a 5/16. Worked much better than I expected and centered the hole perfectly. If I was doing this often I would make from metal and a mill, but they were handy for a one time use tool.

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yella71

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Did it work? is the head on the engine in the car or off on the bench? got pics of that?
 

shepherm

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Did it work? is the head on the engine in the car or off on the bench? got pics of that?

I believe it worked pretty good. I haven't bolted the exhaust manifold back on yet but I tested the threads with a bolt and washers and torqued them down. I don't have any pictures of me using it but here are a couple I just took just now. The head was still in the car, and that's why I wanted something to help drill it straight.

I used 3 different sized end mills, starting with the smallest and working up. As you can see there wasn't much clearance, even when I jack the motor up. That's why the end mills work better than drill bits. They are shorter and stiff, allowing for more room and less deflecting.

To use it, I just started with the smaller 4 flute end mill and pecked, pulled it out to clean the chips and repeat. Then stepped up to the next size until I got to the 5/16.

Note: I couldn't use the other studs in the head because the tolerances were too tight and the jig would not slide over them, so that's why I used the bolts. With the bolts it it flush with the head, not like it is in the picture.

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ckessel

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Cheater! :lol:. You need to perfect it and get a patent on it. Get that baby into production for B, A and Hemi. Probably other engines too. Lots of broken studs in heads out there to save.
 

bm02tj

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Cheater! :lol:. You need to perfect it and get a patent on it. Get that baby into production for B, A and Hemi. Probably other engines too. Lots of broken studs in heads out there to save.

There is one for the hemi gen 3 already being sold
 

ckessel

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If you end up making units to cover the A,B and Hemi[ 2nd gen], I'd be interested in adding those to my Mopar tool stash.
 

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