So the studs I have are a base size of 7/16-14. The size stated for a 7/16-14 tap is size U (.3680). I have a set of drills with a lot of missing pieces, but have a 23/64 (.3594), which is the size just below U (-.0086). I would've already had my answer but someone's borrowing my truck so I'm stuck here... the 23/64 is a loose fit in the stud opening, which makes me wonder do the heads actually need to be drilled before being tapped? I measured one of the original press-in studs and it came out to .3725 (+.0045).
Drilling/tapping for screw-in studs...
- Thread starter Doober
- Start date
It shouldn't be a problem going that route, what is the depth of the hole? do you have to go deeper?
I tapped my camel hump heads without drilling the holes. The pressed in studs were over sized allready so I didnt need to drill the holes bigger. I dont rmr what diameter the over sized studs were but it worked out great. It didnt even take alot of metal out. I used a simple cheap tap and a cheap tap T holder wrench. Just make sure you start out straight and the rest is a piece of cake.
Doober said:
Doober said:
Go ahead and tap the stud holes. As long as the amount of threads are less in diameter than the 'pitch diameter', they'll work just fine. Tap-drill charts allow for 60% threads and you could use a .375 drill and still have plenty of threads. Use some 'red' or 'blue' Locktite on the threads and you should be good to go.
I'd picked up a U-size drill the other day, and it's dang near a perfect fit into the stud opening... \
/ I have a steel block ~1" tall, clamping the opposite side in place with the remaining rocker stud, and using it as a guide for the tap. The opening is just barely large enough for the tap, to the point I will just about have to 'thread' it through the block. My dad made it at work a few months ago, just haven't gotten around to doing this on the heads until now.
/ I have a steel block ~1" tall, clamping the opposite side in place with the remaining rocker stud, and using it as a guide for the tap. The opening is just barely large enough for the tap, to the point I will just about have to 'thread' it through the block. My dad made it at work a few months ago, just haven't gotten around to doing this on the heads until now.
I don't deal with stock heads, but I'm pretty sure they machine that boss down a little bit when they set them up for screw in studs at the machine shop. I'd be taking them to a machine shop.
Doober said:
Tell your dad that standard size taps are usually .005 oversize. Letter X drill is about the right clearance for the tap.
Hitman said:
That's true. They make two styles of screw in studs. The ones with a hex machined on them are intended to be used on heads that have the stud bosses milled flat. There are also screw in studs that have no hex, that are recommended for use on bosses that have not been milled. You might run into clearance issues between the rocker and stud with those studs.
Well let's hope not
All the charts I've read show a U-size for a 7/16-14. My dad's been a diemaker at GM the past 20 years, thanks for lookin' out though 8) I chose studs that are close to the same height/threaded length as the stockers.
All the charts I've read show a U-size for a 7/16-14. My dad's been a diemaker at GM the past 20 years, thanks for lookin' out though 8) I chose studs that are close to the same height/threaded length as the stockers.
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