I think the challenge is finding a machine to practice on, I'm lucky as my friend has the lathe and mill. In turn I will make all the bullets we could posssibly need.
Protect the relationship, a friend with machines is a friend indeed!!!!
EDD, I did not think about 2 rotary files but it makes sence.I did use alot of motor oil for cutting fluid and cleaned out the chips often.
OK...I suggest that you get some machining lube...Tap Magic...Cool Tool or just some stinky black cuttin/threading oil. Motor oil has a tendancy to lube the surface of your cut and cause gouges when it starts cutting again. Also if if is sliding over the surface and then cutting, I could well be "work hardening" the surface slightly.The problem I had was not getting all the chips out of the hole bored in the steel.
LIKELY the problem! An acid brush will help if you don't have some compressed air to blow the chips out with.The idea was to first see if I could bore the chamber and profile of the bullet nose befor attempting hours of work on anything else.
Well now you know...cool huh? So all the chips built up in frount of the nose shape in the little excess space from the pilot hole I drilled first.
Next time I will cut the die to length and bore out the top of the die first. Maybe this will allow the chips to move foward rather then bunch up. I'll also do a better job of keeping the file teeth clean.
EXCELLENT idea.
I don't know the type of steel. It was scrap I found and friend thought it looked like "cold rolled" typical steel.
Cold rolled steel, though easy to machine, can be a PITA to get a good finish on/in. It tends to tear and gouge with fine cuts.I don't know though. It worked for practice.
CRS is great for practice...and again it is free machining so you can get the hang of the process.
So I'll need some more study time but how does one polish out a couple thou from the inside of the bore to get a perfect sized and round chamber?
One was is to use a light oil with wet/dry paper in a wooden stick. Another is to find a Cratex stick. An still another is to use a fine lapping compound on a piece of wooden stick, OR a piece of brass. Oh yeah, keep your RPMS a bit slower while polishing too. I will try some solid brass of proper size to polish with next. All I did with these dies is use some Flitz on a wood dowl chucked in the lathe.
BTW..I'd guess without seeing it, that the tearing I was talking about is why you went big quickly. Danged CRS!!!!Got it nice and smooth but either my technique or the flitz polish took alittle to much.
Flitz is VERY fine grit so I'd still go with the tearing of the finished surface. Another thing I just thought of, perhaps you were running the machine a bit fast. Slow is almost always better when machining for finish.
Thanks guys I'll keep my progress updated. To bad the machine is a half hour drive away. Can't get out as much as I would like, daddy day care seems to be a full time job with alot of overtime.
BT