Reducing Bolt Diameter

[CNC Apps Guy]

.003" isn't much. That may not even really be enough to actually cut even with a sharp HSS tool bit. It may just rub and leave a nasty finish. IMHO of course.

If it were me and I had a manual lathe at my disposal, I'd figure out a way to chuck up a Dremel or die grinder with a fine stone and use that. It will produce a better finish and you can control size better than turning that small amount off.

JM2CFWIW

 

[ntsqd]

When most everyone else is looking to tighten up the bolt to action fit I'm wondering why the OP wants to go in the opposite direction? Concern about function while dirty? Too tight & binds when clean now?

I too would look into having it ground, or doing as CNC guy suggests. It probably isn't so hard that grinding is the only option, but given the small dimensional change desired combined with its relative hardness choosing the right insert and then getting it to cut seems pretty risky.
In absence of having a tool post grinder my boss at the Vintage Touring/Race car shop (a Tool & Die guy by training) had an extended QC tool holder with a Makita die grinder hose clamped onto it that we used for ID and OD grinding when needed. Lest anyone scoff at the hose clamp, know that typically 4 of them are all that holds a Top Fuel Dragster or Funny Car engine in the chassis. Buy good ones like ABA.

 

[DSheetz]

Stainless steel hose clams have and are used in a lot of applications that most people wouldn't think of .

 

[25WSM]

My lathe will take less than .003 and leave a nice finish. Turn the speed up and the feed down. Use a good cutting fluid. I do this on my crowns and on the 30 degree cone on the chamber end and don't even have to sand them. If your not sure you can do it just use sandpaper. Doesn't take much to drop .003
Shep

 

[beveridgek]

trying to turn .003" off of a diameter means 0.0015" per side. That's your depth of cut. I standard insert tool will have a tool nose radius of 0.005" at a minimum, which means using a cemented carbide tool that you have to grind yourself.
If you have a lathe, just polish with crocus cloth, and finish to whatever finish you want with polishing compound.
DO NOT give the paper a full wrap - always hold it with 2 hands so if it hangs, you can turn it loose.
Full wraps can snatch your fingers right off, even on a lathe with a toe brake.
If you're not experienced with lathes, take it to your gunsmith. Otherwise, you could be pulling your trigger with your ring finger, or worse.