I need to tap an extra alternator bolt and have never done it before. I imagine it cannot be too hard but since I have never dont it and nice rundown of the steps involved would be nice. I can get the tap /depth sizes out of the helms manual and I imagine I could get the tap set at home depot.

Any help on this would be nice.

 

It will most likely be a metric tap that you will have to find a Sears, Harbor Freight, or one of the more dedicated tool suppliers. You just find what threadpitch/diameter to tap the hole to, then get the matching drill bit for that tap. There are tap/bit tables all over the internet.

Like this one: http://www.simetric.co.uk/sidrill.htm

For the depth, just wrap some electrical tape on the drill bit at the appropriate depth, or use a depth collar.


Drill the hole, and start the tap. Grease on the tap helps to catch shavings a cut the threads easier. Just keep on twisting and backing it out every 5 turns or so to clear the tap. Its a walk in the park

 

Thanks man thats what I needed. My alternator is fluctuating voltage and I think its cause its moving a little cause I do not have enough bolts. I apprectiate the help.

 

One more question, when using the tap I assume you twist it in somehow by hand not using the drill? Is there something special that holds the actual tap?

 

They are square on the end. You can get a tap handle or use an adjustable wrench...


Blake

 

Great thanks again.

 

You need a drill bit that is the "root diameter" of
the bolt. Or just a hair bigger, not much. There
are tables of drill size vs tap on the Internet.

To tap without getting stuck, you need to use a
technique that prevents the tap flutes from
loading up with the swarf and binding. If you bind,
you break off hardened steel in the hole (bad).
Use a cutting oil (or WD-40 or ATF) and for every
full rotation of the tap, back out one, ahead 2,
back one, ... so that the thread swarf comes out
as chips, not strings. Back all the way out every
few advances and unload the flutes. Take your
time, she's a virgin after all.

 

From The American Heritage Dictionary.

swarf (swôrf) n. Fine metallic filings or shavings removed by a cutting tool. [Of Scandinavian originAkin to Old Norse svarf.]

I just love learning new ****.