I finally have my mill up and running. I purchased and installed a mill vise, bought a variety of center cut 4F carbide flat end mills and a variety of collets to hold the end mills. I also have a face mill but need to get carbide replacement inserts for the HSS one that it came with. So far I have used the mill to flatten a few damascus billets so they are uniform in thickness. Although I have press dies, I would like to use the mill to cut some patterns into the damascus billets. I also would like to take bars of brass or 416 SS and make some finger guards that I can cut to size once my knife is ready for them.
So my question is what size round carbide end mills should I be looking for? I assume they should also be 4F. I did a search in the forum but did not find much on the subject. I do not have a CNC so these will be cut manually.
What is it you are trying to shape?
Karl B. Andersen
Journeyman Smith
For brass bronze or copper I mostly use 2 flute end mills.
|quoted:
What is it you are trying to shape?
Karl I am trying to make a 6 to 12" bar of steel or brass that I can cut individual finger guards from one at a time. Like a loaf of bread. I want to rough cut out the lower part of the finger guard with a ball end mill but the full length of bar. Once I cut off say a 3/4" piece, I will center cut the tang hole and finish shaping the guard. I hope this makes sense.
|quoted:
For brass bronze or copper I mostly use 2 flute end mills.
Thanks Matthew. I was considering Carbide ball end mills so I could also use it for making damascus guards.
I've had issues with carbide on nonferrous, softer alloys tend to be "catchy" and snap carbide if I didn't get the speed and feed just right. The two things that saved me the most on end mills was finding the right speeds and a concentrated stream of coolant to get the chips away from the cut. Coolant also saved me a lot of drill bits as well. Come to think of it, it also made surface grinding a lot cleaner and easier as well. I guess I really like coolants.
"One test is worth 1000 'expert' opinions" Riehle Testing Machines Co.
|quoted:
I've had issues with carbide on nonferrous, softer alloys tend to be "catchy" and snap carbide if I didn't get the speed and feed just right. The two things that saved me the most on end mills was finding the right speeds and a concentrated stream of coolant to get the chips away from the cut. Coolant also saved me a lot of drill bits as well. Come to think of it, it also made surface grinding a lot cleaner and easier as well. I guess I really like coolants.
Thanks Kevin for your response. Since milling is new to me, tips like these are very helpful.
It has been a LONG time since I was in school for machining, but somethings that have stuck with me as use full.1) coolant, cutting fluid and oil are not the same thing and all three has there uses, those uses are also material dependent. 2) tooling is material specific the rake and edges angles material coating and number of flutes is specific to materials and type of cut. 3) speeds and feeds are critical for any operation, in some cases to fine a cut or to slow a feed can be almost as bad as to high. 4) all the tables are base line, and will need to be adjusted to your machine what my shop teacher called the "rule of 5" 0.5" 500rpm 50FPM is a conservative base line for cutting/drilling in fact a better base line milling steel with HSS end mills on my machine is 750rpm 75FPM but it isn't as easy to remember:) just remember as cutter size drops RPM goes up.
coolant cools and flushes chips it does not aid in cutting, cutting fluid aids in cutting and will help carry heat from a cutting edge, oil makes thing slippery.. oile should be used on the machine not the part. coolant in situations were heat build up or chip build up is an issue. (situations like kevin mentioned) cutting fluid is great for things like drilling tapping. or turning of some materials.
What kind of end mill s you need for a specific job can be difficult to figure out, carbide is not the answer to everything. I find the best bet is to look in the tool catalogs MSC Tavers what have you and start with there recommendations they will list what each type of mill is designed to cut. I use HSS 2 or 4 flute cutters for 99% of my work on the mill only using the carbide for a few situations. you can look all this up on the machining forums or in machinery handbook (AKA machinists bible) if you would like more details. Machinery handbook is especially handy, so much so that is what the small wide drawer in most machinist tool boxes is for , to hold that book.
MP
I agree with Matt and Kevin. "Surface Speed per Minute" is critical for all machining operations in all materials. You can find the appropriate speed for the material in Machinery's Handbook. A basic formula is: Machine RPM X PI(3.14) X D ( diameter of cutting tool). Then you can read paragraphs concerning the "Travel Speed". or table travel. Seeing as you are doing this manually-start slow. 2 flute end mills work well in AL and other non-ferrous metals. 4 Flute for stainless and other steels. TIN and carbides in all grades were designed for production machining so don't use expensive tooling where HSS will work equally well. There are as many fluids for machining as beers on the shelf so pick a general cutting fluid like pipe thread cutting oil and apply it with an acid brush as needed. Cutting Fluid and Coolant are not the same. Your chips will tell the story- blue/violet is a no no, slow down. Chips are a science in themselves. Fascinating to watch but razor sharp and will grab clothing and hair like a three balled Tomcat so be careful. Hope this helps
I have a tiny bit to add here. One, I've used a 1/4" ball end mill to cut grooves for ladder pattern Damascus with some success. Two, I typically do my guards one at a time and use a 1/2" or 3/4" mill and come in from the side. Haven't tried to do a big bar like you've described. You'd have to go ball end for that.
