anodizing tolerance

[mmca]

So Ive caught the make "your own lower" bug.

I couldnt wait for the Socal build party so I completed a couple of the YellowLogic 80%'ers. Built out a little computer controlled machine to cut out the FCG pocket.

So now Im starting in on a 0% forging from Spike's.

Home anodizing doesnt seem to add any thickness to the parts. But do I need to leave some sort of tolerance for TypeIII anodizing.

Should I ream the hammer/trigger holes to .154 or over size them at .155?

Thanks for your help.

-M

[mmca]

Pic of start of 0% and proof of concept for my cutting machine.

A little scale lower... so cute.

[eaglemike]

Normal allowance for hard ano is .0005 per side for buildup. It also penetrates some, but this doesn't matter, right? So allow .001 for the hole diameter. It can also build up a bit on the edges of the hole sometimes.

all the best,
Mike

[krazy]

Pic of start of 0% and proof of concept for my cutting machine.

A little scale lower... so cute.

wanna sell that little scale lower? its so awesome!

also, could you document your home anodizing, id like to get into this as well, but just doing 1 lower at this point seems pointless for me.

[eaglemike]

Home anodizing is usually soft anodizing - not the same stuff as on the purchased lowers.....

[ERdept]

Type III baby.

Just so you know, I always deal with Tech Plate in Anaheim. I just drive to the back door and drop stuff off and pick up the same way. They have great sales guys that are very helpful on metals and readily answer questions.

[Francis Marion]

Home anodizing surface build up, who knows. And who knows if home anodizing imparts significant surface hardness.

You want hard, black anodizing, not just any type of anodizing. Hard coat processes will build up typically from 0.00025" to 0.0005" external to a surface. The surface finish is a function of pre-anodized surface finish. A machined or smooth surface has a different value than a bead blasted surface. Bead blast- evenly- for an even dull/drab black, leave smooth for a glossy black. I prefer the drab finish.

Ask the vendor for something like:
Hard anodize, black, per Mil Spec MIL-A-8625 Type III.

You also need to know the alloy of the receiver so the vendor can select a suitable process. Your alloy is hopefully a quality material like 7075; find out.

Danco in Santa Ana does good work.

[mmca]

Yeah, my buddy had some of this left over:

http://www.caswellplating.com/kits/aluminum.htm

Looks fine, but I dont know how hard it is. So Im sending out the next couple to a commercial shop to get the Type III.

[mmca]

wanna sell that little scale lower? its so awesome!

I couldn't sell it... its my very first home made gun. Some day I'd like to make an upper and turn a barrel for it.

[krazy]

I couldn't sell it... its my very first home made gun. Some day I'd like to make an upper and turn a barrel for it.

Well, thats awesome nonetheless. Please update us on your anodizing process!