I got all of the bosses drilled perfectly, then on the last one its semi off centered. I know I drilled though the pin but I think it may be on the very edge of it. Would it be better to place a pin though that and then drill another one perfectly through the center from the other side. sortz make it looks like a cross or would weaken it alot. The cam is max 470 lift. I was doing this in prevenative maintenance.

 

i'd say run it as is instead of drilling another hole in the pull out stud

 

Out of curiousity, what size bit, and what size roll pins are you inserting? I am considering doing the same thing to 'Budget 350".

 

I went though 10 3/32 Titanium Dewalt Bits and I am using 3/32 Pins from local shop.

 

the pins are tight but its going ok

 

As long as the hole you drilled thru the stud boss does not totally miss the rocker stud I'd say you'll be fine.
.470" lift is not a lot and you do not need huge spring pressure for a .470" lift cam.

You can hand sharpen the drill bits with a die grinder and a grinding stone.

 

I junked a handful of plain bright HSS drill bits, before giving up.... I'm pulling and tapping now...
...which leaves me with 495 or so roll pins from mcmaster carr ....

 

I have found that whole exercise to be a total waste of time. People that I know who have done it, almost every time, have had something REALLY BAD happen somewhere along the line.... broke off drill bits stuck in the studs (sticking out of the stud into the cast so they couldn't fix it by pulling the stud), cracked the bosses, etc. etc. etc.

Some things just aren't worth half-assing, unless you're racing in a class whose rules forbid guide plates.

A drill bit is supposed to be a cutting tool. Good ones have their tips ground at a small angle; maybe .001"-.0015" difference between the cutter on the leading edge, and the back side of the "flat" plane. They're designed to shave just exactly that much material off per revolution. The "blade" part can't cut worth a crap, if the entire surface of the bit is sitting on the workpiece. If you have a workpiece that destroys a tool, then you have an inadequate tool inthe first place; and "sharpening" it without that little angle, doesn't really improve it any.

See paragraph #2.... except there aren't any classes I know of that forbid replacing wasted drill bits.

 

are you saying sharpening drill bits in general is a worthless endeavor?

I know a few machinists that would have a word to say about that...

 

No, pinning studs.

You weren't drilling dry, were you?

 

oh, I caught that re-sharpening a drill bit wouldn't work... and i'm pretty sure it's possible...


I was drilling dry, cast iron is basically self lubricating.... however the case hardened steel musta killed them....
then again, they were job-mate drill bits, when c-tire had a 90piece set of small drill bits for $8 or something, I grabbed it... used up like 8/12 of the 3/32" drill bits, and decided it was too much work...
I have that nifty stud pulling/tapping jig that I was itching to use anyway...

 

Cast iron is, but what are the studs made of?

 

On to answering the question, you should not drill a new hole perpendicular to the existing one. It will result in too much material removal.

 

The studs are made of case hardened steel.
In other words drilling thru the surface of the stud is difficult and wears the drill bit.

Patience, moderate pressure, moderate speed and sharp drill bits are nessessary. I sharpen drill bits by hand all the time.

Other than that it is not hard to do.

 

HINT: You aren't required to use guide plates with screwed studs:

 

Yup, guideplates are just for heads that don't locate the pushrod with the narrow pushrod holes. You also wouldn't need guideplates if you are using self-aligning rocker arms with later model heads.

 

It was a socratic question.

 

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I just thought there was an echo in here....damn philosophers....