Oversize Head Stud

TruckYou

TruckYou

New member
Joined
Dec 21, 2016
Messages
132
Long story short, I ended up going to 14mm headstuds. I got the block up on my Bridgeport yesterday to find out, I don't have enough table height adjustment to use this mill. Iv read a bunch about guys drilling with cordless drills and what not, and it just seems super Leary to me. I saw BHJ sells a Register Plate, which bolts to the deck and has 14mm holes for the tap and 12mm bushings for the drill bit. The stock studs are 12m, I need to prehole with a 12mm, then tap with a 14mm bottoming tap. The bhj kit is awesome, but it's not in the finances to spend $1500 for a one time use.

Has anyone else drilled/tapped there block? How'd you do it? Am I over thinking this?

I even went to the extent this past weekend of building my own miniature fixture plate, like bhj, using 3/4" aluminum, used the head gasket to find center of the stud holes, and drilled 3 holes in the plate, so I could bolt it to the deck with 2 M12 and use the 3rd hole to drill. But after trying it out I realized I was a thou or 2 off on my center punch and the bolt threads we're trying to bind, when I was bolting the plate down



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Damn it. Didn't mean to post in Forsale section... Sorry.

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Subscribed. I just got done looking for any other option other than tapping my block and didn’t find anything. I got my rocker boxes back from the machine shop. Just need to find out away to get the block done.


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seems like it would be worth it for someone who already has this $1500 plate to loan it to you for an evening for like $100.
 
Ya that would be awesome. I'm just curious other members opinions. I can make a new plate, to stablize the bit. From the outside looking in, it seems to me that, a 12mm pilot isn't going to remove very much material, and should follow the original hole with minimal deflection. Free hand drilling could oval out a hole, if off by a degree, but if I could fab a plate, mill all flats square , and drill the holes straight and to as tight of tollerance as possible to the actual shaft diamtere of the 12mm bit, it would be a piece of cake to drill. On my first attempt, I should've used a center punch the exact same size as the Headstud hole in the head gasket, to spot center, but I didn't have that size so I used a undersized center punch, and that slight difference was enough, I didn't dare move forward with it

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TruckYou said:
Ya that would be awesome. I'm just curious other members opinions. I can make a new plate, to stablize the bit. From the outside looking in, it seems to me that, a 12mm pilot isn't going to remove very much material, and should follow the original hole with minimal deflection. Free hand drilling could oval out a hole, if off by a degree, but if I could fab a plate, mill all flats square , and drill the holes straight and to as tight of tollerance as possible to the actual shaft diamtere of the 12mm bit, it would be a piece of cake to drill. On my first attempt, I should've used a center punch the exact same size as the Headstud hole in the head gasket, to spot center, but I didn't have that size so I used a undersized center punch, and that slight difference was enough, I didn't dare move forward with it

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Those magnetic base drills work great. Just used one to enlarge the prechamber hold down bolt holes on a Cat 3606.
 
Why not send it to a machine shop and let them do it. Might have $200 invested in them drilling and tapping the holes to 14mm
 
DISTURBED said:
Why not send it to a machine shop and let them do it. Might have $200 invested in them drilling and tapping the holes to 14mm
Click to expand...

x2 You said you're only planning on doing it to one engine. It seems like a cheap alternative and very low risk.
 
If I was only doing one I would probably just use a old head as a drill jig.
 
If you're central NY, contact Mark at TBR automotive and diesel machining, in Syracuse. Hes done a lot of machining for me, and he does a lot for milton cat since they're next door to him almost. Worth a shot, Marks a smart guy and great to deal with.
 
CompD neve disappoints. Alot of helpful information. I was actually contacted by someone who offered to let me borrow there BHJ plate. Super cool. Thanks everyone , thanks Comp D

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