Drilling and tapping a hole

[Administrator]

Help me settle another breakfast table bet with Don.

The question is this:

Laying aside the issue of access, would you consider yourself capable of drilling and tapping a hole in an engine component and willing to undertake the task for some reasonable benefit?

Bill

[hanleyclifford]

Help me settle another breakfast table bet with Don.

The question is this:

Laying aside the issue of access, would you consider yourself capable of drilling and tapping a hole in an engine component, and willing to undertake the task for some reasonable benefit?

Bill

Yes. I have done it when eliminating the "freeze/expansion" plugs on the manifold.

[Al Schober]

I voted 'absolutely' as I have done this successfully. Being able to use a drill press for the drilling is a big plus, otherwise you need some sort of fixture to hold the drill (and tap) square. Doing it freehand is asking for trouble as the hole and threads are likely to be off alignment. Often the mating part can be used as a fixture with suitable bushings around the drill and tap.

[sastanley]

"Absolutely"

I just recently did so when I enlarged my side plate from 3/8" NPT to 1/2" NPT.

I will confess I did the same as Al, and took the plate off and used my drill press & tapped the plate in a vice, so access and alignment were not factors.

However, I have also drilled the block in the boat to repair my failed 1/8" aft block drain and re-tap to 1/4". That was one of my first tasks when the old galvanized piece fell off the motor into my hand the first winter.

The 23/32" drill bit for the 1/2" tap cost 3 times what the tap cost!

[ndutton]

As this is a do it yourself forum, I would think drilling and tapping would be a basic skill. Sure, there are members who don't consider themselves mechanics but I read over and over their personal satisfaction as they discover they can do it.

For those who don't know or haven't drilled and tapped before, give it a try, it's not that hard.

[rpowers]

Yes!

I was really apprehensive about tapping new threads into the engine block for new manifold studs. The old bolts had stripped the threads in the block.

I found it to be easy (soft metal on the block) and VERY rewarding.

Careful to go in straight, and not "screw"-up, things went well.

Using a helicoil and JB weld, now I have a well-seated manifold via studs.

-Rick

[joe_db]

On my old engine, I did it by HAND - turning the tap with a wrench due to lack of access.

Of course this may help explain why I got a new engine

[tenders]

Is this a poll for the rumored A4 fuel injector/supercharger kit?

[Administrator]

Is this a poll for the rumored A4 fuel injector/supercharger kit?

Uh, no.

Bill

[ILikeRust]

Absolutely.

I did it a couple times on my ongoing rebuild.

I made the Moyer Modification to the accessory drive, which involved plugging the existing oil drain hole by tapping it and JB Welding a screw in to permanently seal it off, and then drilling a new hole in a different location.

I also snapped off one of the exhaust manifold bolts, so I had to drill it out and re-tap the hole to install the Moyer studs.

I have no problem drilling and tapping holes - this is far from the first time I've done it.

I think you might find a "continuum" of do-it-yourself types here - some will do basic engine maintenance and simple upgrades, and then there are the crazy people like me who will take on the complete tear-down and rebuilding of the whole engine.

Part of the question is how many people who consider themselves "mechanically inclined" or "somewhat handy" have tap & die sets, or are willing the spend the money to buy them if they don't already have them. I have found that there's a certain point at which some guys decide it's not worth it to buy a certain tool they don't have, because they're very unlikely to use it again. Taps and dies seem to fall into this category for a lot of people.

Of course, if you're putting together a "kit," you could include the correct drill and tap in the kit.

[sastanley]

Is this a poll for the rumored A4 fuel injector/supercharger kit?

Uh, no.

Bill

Darn.

[ILikeRust]

By the way, I also cut threads on several studs. I somehow ended up with the wrong number of "long" head studs versus "normal" ones. I had too many of the studs meant for the lifting eye, which are about 1/8" longer than the regular head studs. So I had to cut about an extra 1/8" of thread and grind them 1/8" shorter - basically move the threaded section 1/8" up the stud and shorten the overall length of the stud to match the regular ones. No biggie. Worked just fine.

[TomG]

Many years ago, one of my most favorite jobs was as an apprentice electrician. I learned many, many valuable skills, but what I most remember from those days is you can do most anything with the proper tools, the proper knowledge, and the proper time. Drilling and tapping a hole isn't that difficult. Now drilling and tapping a hole in an exact spot might be something I would not be willing to invest the time and money in to do it myself. Generally speaking though, I would be comfortable drilling and tapping (in fact I'm installing a new mast gate and two eye straps this afternoon using drilled and tapped holes) if there were an appreciable tolerance for hole placement and a purchase of expensive equipment weren't required.

If it's got to be on the gnat's ass, I might pass. Same day, same way, I'm okay.

[ndutton]

[Off topic]
Tom,
As you spent some time in the electrical industry you should be familiar with NOALOX. I strongly recommend slobbering it on the machine screws before installation. It virtually eliminates corrosion and dissimilar metals problems between the stainless screws and the aluminum mast in the future.

[TomG]

Neil, that is a great point that many folks don't consider (or even realize). Noalox is probably the best out there. OxGard is also good and readily available. The reason I am redrilling and retapping the mast gate is because the PO didn't use an antioxidant and the screws corroded and broke off.