80% lowers drill bits

[Darklyte27]

I bought a drill bit kit for the 80% lowers http://www.buckeyetactical.com/jugge...l-tooling.html
, surprisingly it didnt come with a 7/16ths that this instructions said to use

http://cdn.shopify.com/s/files/1/0218/5770/files/Jig_Manual_80_Percent_Arms.pdf?106

what are you guys using?

[milotrain]

Just use the 3/8" bit. 1/16th won't matter on those holes, they are just through holes to get you started on the trigger slot.

[Whiterabbit]

yep.

But to answer your question, I have a local machine shop supply I buy bits from for metal. harbor freight and home depot for wood and delrin, and the nice HSS from the machine shop supply for metal.

[101st Airborne]

HSS bits will work fine in aluminum.

[Darklyte27]

7/16ths is for the brown hole which seems to be the width of the safety selector?...

[Whiterabbit]

3/8 for safety selector.

[Darklyte27]

3/8 for safety selector.

please understand the thread before responding, this is about the 7/16ths bit thats required to drill the brown dot in the PDF.

[kcstott]

Still thats the finished size and I sure as hell would not drill to finished size.

[ar15barrels]

please understand the thread before responding, this is about the 7/16ths bit thats required to drill the brown dot in the PDF.

I'm not letting anyone drill my brown hole!

Really though, it does not matter what size you drill it as you will be milling it out later...
Threads like this are why people who don't understand blueprints should not be machining.

[Whiterabbit]

please understand the thread before responding, this is about the 7/16ths bit thats required to drill the brown dot in the PDF.

read your post. 7/16 is NOT the width of the safety selector. No matter what else was meant.

[milotrain]

KCstott, I may be reading the prints wrong but I see the finished size for that pocket to be .438 (+- .010), but no one bothers with that because it's a non critical dimension so they just use a 3/8EM, and drill smaller so that the endmill is a finishing tool like it's supposed to be. However, because that pocket is so non critical I don't see a problem drilling it 3/8". In general though you should of course never drill to a finished size. I do often drill under and use an EM as a ghetto reamer and that works pretty well, usually just a hair tight.

Any generic POS 7/16th drill you find at a local hardware store will do just fine for this application. If it makes you feel better go buy one.

[Sticky]

That hole is the rear of the FCG pocket and a 7/16" hole is the proper size to drill or mill it (I mill, not drill, but... ) a HSS bit will work fine and that is what I'd use if I were to do the finishing on a drill press.

[ar15barrels]

the print says .376 +/- .001

Drill bits cut larger than their nominal dimension.
Best practice is to drill 1/64" undersized and then ream to final desired dimension.

[Whiterabbit]

redacted. got quoted. bummer. I saw the error of the post, just couldn't delete it in time.

[kcstott]

KCstott, I may be reading the prints wrong but I see the finished size for that pocket to be .438 (+- .010), but no one bothers with that because it's a non critical dimension so they just use a 3/8EM, and drill smaller so that the endmill is a finishing tool like it's supposed to be. However, because that pocket is so non critical I don't see a problem drilling it 3/8". In general though you should of course never drill to a finished size. I do often drill under and use an EM as a ghetto reamer and that works pretty well, usually just a hair tight.

Any generic POS 7/16th drill you find at a local hardware store will do just fine for this application. If it makes you feel better go buy one.

And thats fine. I just would never drill a hole that was called out final size .4375 with a 7/16" drill.

yeah the pocket is not that critical but I'm a PITA tool maker and I like things to match the print... Until they don't then I look at ho w critical the dimension is and say oh well it's not a big deal.