How close do you indicate a 80% lower?

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[ARCHIVED THREAD] - How close do you indicate a 80% lower?

Posted: 4/30/2015 9:45:40 PM EDT

Don't know how I got upper there, it should have been lower.

I'm milling a couple of 80% lower. And was curious how close the top deck needs to be indicated in when doing the trigger group pocket.

Thanks,
Bob

Posted: 4/30/2015 10:01:10 PM EDT

[#1]

Lowers?

Posted: 4/30/2015 10:26:04 PM EDT

[#2]

I just clamp the fixture to the table and go.

Posted: 4/30/2015 10:26:40 PM EDT

[#3]

How in the world do you keep all the chips from going everywhere. I have an 80% lower I was working on and I stopped because there was a covering of aluminum chips stuck all over me and everything else.

Posted: 4/30/2015 10:30:51 PM EDT

[#4]

I don't think I'd mill a fire control pocket in an upper. Just sayin'...........

Now if we're talking about lowers, there's no reason you shouldn't be able to get <.001" in any decent machine vise. I'd say absolutely
not more than .005" lengthwise and .002" across.

Posted: 4/30/2015 10:33:39 PM EDT

[#5]

How in the world do you keep all the chips from going everywhere. I have an 80% lower I was working on and I stopped because there was a covering of aluminum chips stuck all over me and everything else.

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If you have a problem with chips everywhere, machining prolly ain't for you

(If you think aluminum chips are annoying, try dealing with nearly microscopic slivers of tool steel or titanium.....)

Posted: 4/30/2015 10:37:29 PM EDT

[#6]

Quote History

Quoted:
How in the world do you keep all the chips from going everywhere. I have an 80% lower I was working on and I stopped because there was a covering of aluminum chips stuck all over me and everything else.

View Quote

I use a loc line shop vac and loc line air on the opposite side. Keeps the chip from galling up on the EM, keeps the EM cool and it's a lot more fun to see what you're doing. I have a 6hp 10gallon shop vac. Pretty sure I could use 3 of them and still not get all of the chips, but one gets 80% of them.

Posted: 4/30/2015 11:23:51 PM EDT

[#7]

Sixtysixduece,

Thanks for the info. I've always been able to get it less than .001, but was just curious as to what others shoot for.

Bob

Posted: 4/30/2015 11:25:42 PM EDT

[#8]

Use a shop vac to clean up, but don't pay that much attention to them. I just try and keep the endmill clean of them.

Bob

Posted: 5/1/2015 1:46:04 PM EDT

[#9]

I use a can of WD40 on aluminum to keep the endmill from being gummed up, and it helps keep chips from going everywhere.

Nice thing about aluminum chips is they don't scratch your skin and dig in like steel chips. They don't mark up floors or rust when tramped into the house.

Back on track, I think depth is dependent on what trigger group you are using. You need to be able to rotate the safety as an upper height, but you don't want to punch through the bottom.

Posted: 5/4/2015 5:51:23 AM EDT

[#10]

Quote History

Quoted:

If you have a problem with chips everywhere, machining prolly ain't for you

(If you think aluminum chips are annoying, try dealing with nearly microscopic slivers of tool steel or titanium.....)

View Quote View All Quotes

View All Quotes

Quote History

Quoted:

How in the world do you keep all the chips from going everywhere. I have an 80% lower I was working on and I stopped because there was a covering of aluminum chips stuck all over me and everything else.

If you have a problem with chips everywhere, machining prolly ain't for you

(If you think aluminum chips are annoying, try dealing with nearly microscopic slivers of tool steel or titanium.....)

Had bunches of tiny chips fall inside both if my leather work gloves. When I pulled my hands out hundreds of small metal splinters became embedded in my palms. It took weeks for me to find and pullall of them.

Posted: 5/4/2015 7:02:10 AM EDT

[#11]

Had bunches of tiny chips fall inside both if my leather work gloves. When I pulled my hands out hundreds of small metal splinters became embedded in my palms. It took weeks for me to find and pullall of them.

View Quote

Do not EVER wear leather gloves when using mills and lathes. Slivers are the least of your concerns. Get an ungloved finger caught in a cutter, you get your finger cut. Get a leather glove wrapped up in there, it'll break your arm or worse.

Use Nitrile or other disposable gloves that tear with relative ease.

Posted: 5/4/2015 8:09:04 AM EDT

[#12]

Quote History

Quoted:

Do not EVER wear leather gloves when using mills and lathes. Slivers are the least of your concerns. Get an ungloved finger caught in a cutter, you get your finger cut. Get a leather glove wrapped up in there, it'll break your arm or worse.

Use Nitrile or other disposable gloves that tear with relative ease.

View Quote View All Quotes

View All Quotes

Quote History

Quoted:

Had bunches of tiny chips fall inside both if my leather work gloves. When I pulled my hands out hundreds of small metal splinters became embedded in my palms. It took weeks for me to find and pullall of them.

Do not EVER wear leather gloves when using mills and lathes. Slivers are the least of your concerns. Get an ungloved finger caught in a cutter, you get your finger cut. Get a leather glove wrapped up in there, it'll break your arm or worse.

Use Nitrile or other disposable gloves that tear with relative ease.

No long sleeves!!!!

Posted: 5/4/2015 1:47:37 PM EDT

[#13]

your not going to have any problems at .015 off on length and width. Depth -0+.03-.06 Is no problem

Posted: 5/4/2015 3:12:43 PM EDT

[#14]

Quote History

Quoted:

Back on track, I think depth is dependent on what trigger group you are using...

View Quote

Depth is 1.249 +/- .010 no matter what FCG you are using

Posted: 5/4/2015 7:07:46 PM EDT

[#15]

Quote History

Quoted:
I use a can of WD40 on aluminum to keep the endmill from being gummed up, and it helps keep chips from going everywhere.

Nice thing about aluminum chips is they don't scratch your skin and dig in like steel chips. They don't mark up floors or rust when tramped into the house.

Back on track, I think depth is dependent on what trigger group you are using. You need to be able to rotate the safety as an upper height, but you don't want to punch through the bottom.

View Quote

If your doing Mil-spec... Wouldn't the depth be the same No matter what Trigger Group your using? So it would not be Dependant upon that.

Silly me I always thought Mil-spec was Mil-spec

Do they make different lowers for different Triggers?

YES that was a sarcastic question.

Posted: 5/4/2015 8:28:13 PM EDT

[#16]

I indicate off the deck, level using the deck too. I strive for 1.249. My DROs read to .0005 but they are not rated to be that accurate over nearly any distance.

In short, strive to be as accurate as you can. The tollerances should allow for any short comings, if not, you need better equipment or more patience. I need both

[ARCHIVED THREAD] - How close do you indicate a 80% lower?

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