[Jag Daddy]

Hi All:
Tonight I ran into a bit of an issue and was looking for some input from you guys. I need to make a new threaded power steering/AC pump bracket rod. I have the original but it no longer fits since I moved to GT 40 heads. The threaded holes in the GT40's are 7/16 where on the originals ones where 3/8's I was thinking of going to buy some 7/16 round stock and just recreate the part on the lathe.

I was thinking of either threading one end 7/16 and then machining the rod down to 3/8's so the brackets still fit and threading the other end 3/8 like normal. Or I can drill out the brackets (as long as there is enough material there) and just using the 7/6 rod. I like the latter because it should be a stronger part

The question is what type of round stock should I look for? Any other ideas I'm open to as well
Thanks
Mark

 

[ericnova72]

Plain old cold rolled steel (CRS) is plenty, like 1018 or 1020....it doesn't need to be anything fancy. Anything with a better alloy would also work, just isn't needed and more costly unless you are working from a pile of scraps and leftovers.

If the bracket has enough meat around the hole, I'd just drill it ovrsize and go.

 

[2old2fast]

What size hole does a 3/8" helicoil use ?

 

[ericnova72]

What size hole does a 3/8" helicoil use ?

Letter "X" drill is the called for size(.3970") for 3/8"-16...I've seen 25/64" used which is .3906" but you have to be a little more careful with the tap as that is tighter on the minor diameter, tap has to cut more.

Can't just put a 3/8" helicoil in a 7/16" hole if that was what direction you were thinking. You'd have to use something like a TimeSert "Big-Sert" which for 3/8"-16 would go into a .484" drilled hole. Might even be able to do it with a standard Timesert, but it will still leave some remnant of the 7/16" original thread in the hole, won't be a clean hole for the timesert tap.

 

[Jag Daddy]

Cold roll is easy to get and I can easily turn that. I'll have to see how much is in the bracket holes. I like the idea of upgrading to the larger diameter anyway
Thanks
Mark

 

[alwill923]

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[PHWOARchild]

Take some pictures of the parts you want to assemble. Look at the old bolt, do the file test on an unthreaded portion to see if it is a hardened steel.