Jind of oil for drilling and tapping trunion?

[Deadeye008 2]

I'm at the point where I'm going to drill and tap my trunion for a bullet guide but I need to know what kind of oil to use. I will most likely be using a hand drill. I imagine the trunion is very hard so I was just wondering what everyone else had used to aid them in drilling and tapping it. Thanks

[IndyArms 10,186]

pretty much any oil will do... I have used a spray lube similar to wd40 when I was threading my barrels. The oil is to help reduce friction, and to help keep the metal cool. (Friction = heat)

 

Try some lightweight motor oil, like a 5W-30, or similar...

 

I dont think you will have any problems...

 

Remember when threading... 1/4 turn of die bite, back out, oil, another 1/4 turn of die bite, back out, oil, etc...etc... keep the shavings out of the cutting area, and TAKE YOUR TIME!!!!! ( Thats why I like the spray lube, is because it clears out the shavings for the next die turn...)

 

[vanhoutster 0]

It may sound wierd, but ATF, especially dexron/mercon works great. They add all sorts of friction modifiers which make it work well. I use it a lot when milling hardened steel.

Pretty much any oil will help A LOT.

[kresk 10,063]

There was a thread on this early in the year and odd as it may seem some folks swore by beeswax as the best drilling lubricant for the Saiga receiver alloy.

[vanhoutster 0]

yeah, Beeswax works really well too. it helps keep metal from clogging the flutes on the bit to. best to wax your bit first, then use a light machine oil(or atf) as a cutting fluid.

[Deadeye008 2]

Thanks for all the quick replies. I'll let ya know how it goes when I try it out later today.

[meangreen 0]

I just used a cobalt drill bit at slow rpms and it cut through the trunion

like butter.

[Bvamp 604]

when cutting metal, (drilling milling and sawing are all cutting, how I was taught), the trick is to not smoke the tool and to use oil. motor oil is fine, but dont use drain oil. it works, but can have shavings and some nasty impurities in it that are best left for your furnace filter to take out when you use it to heat your house. low rpm, low pressure on the tool face, and much oil (but not so much to make a mess) for lube and cooling, like was said. if you see smoke, you are going too fast. I have drilled leaf springs with cheap drill bits using motor oil and a screw gun (for low speed). two months ago actually. an air tool bit is really for sheet metal and softer alloys, not dimensional steel work, as I was told.

 

like indy said, wd40 is a good lube, although not a very good high temp lube, like motor oil is. I have used a drop of wd40 to thread milspec electrical connectors (you have them on your boat, usually, and you mil boys have them on your electrical equipment), or any other collar threaded connector that is tight. just a DROP works. this also works like was said, on threading tools, bolts, pretty much any steel to steel thread. I will use it when attaching lag bolts to wood, as well, if it is a really tight fit. the other thing that I will use in place of wd40, not for cutting mind you, is something called PB blaster. it is basically liquid wrench mixed with a light machine oil, like wd40 in spray can. keep in mind wd40 is also a grease cutter. using it for a lube on a grease joint will solve the problem temporarily, but it will ultimately make things worse, if you dont take the time to properly lube your part with the correct compound. this is why it is a good idea to keep it away from machine tools.

 

if you want to find a good prototype machinist, or want to know who is any good in the local mechanic shop (or whatever), look for a smoke layer in the tool room. it will start about 4-5 feet from the floor, and go up several feet, and is hard to get rid of quickly without a proper exhaust fan. this means (when you see it), that the guys either dont know what they are doing, or rush thier work. granted, it isnt a 100% rule, but this is what I have been told and shown by machinists I know. (the next thing to look at is tool organization, by the way, and then cleanliness of metal shavings, which can ruin a piece of work)