bump die finish

  • Last Post 09 February 2021
porthos posted this 09 February 2021

is a reamer finish good enough for bump dies? i would think so, but, thought i would ask

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Tom G posted this 09 February 2021

Yep, use lots of cutting oil on the reamer and clean the flutes often when reaming and you should be OK. I mostly used Rigid brand pipe threading oil to cut chambers and it worked very well. It has ( I think ) sulfur in it to aid the cutting. It's dirty to use but it's worth using. 

It wouldn't hurt to polish your new die with some very fine sandpaper on a stick to get the bullets to eject from the die with less force. Lubing the bullets with some spray case sizing lube will also make things go a lot easier. 


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  • Bud Hyett
Shopdog posted this 09 February 2021

Clean and lubed,echoing Tom G above,is SOP here.

We keep some $$$ cutting fluids here that earn their spot on the shelf on bullet dies. These are the lubes that get broken out for very tough machining chores. Can be diluted with sulphur based fluids but the sorta defeats their mission.

Castrol safety draw 722X is some 1st class heavy duty stuff. Tap Magic Xtra thick is another. You're going to have play with your finishes to get exactly what works. I usually can get one nicely done right off of a sharp reamer. Good luck with your project,it's very rewarding(for me) dialing in bump,and swage dies. It really can open up some different avenues in fitment.

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