Milling tool types and sizes?

[negatronix]

Hi.

I have a few tool related questions that I hope someone will be able to help me with. I am trying to put a package together of commonly used sizes, and avoid buying whole sets of both endmills and collets. Most of my work will be rather long(8-10") straight cuts, with 1-3" radiuses. Nothing really fine. I will be using a Grizzly GO755.

1) Is there a good general size for an endmill to start learning with. I am looking to just do straight cuts into 1/4"-3/8" steel plate. Is going bigger usually better. Less breakage, and tool wear.

2) What type of tool would I use to "plunge" into a piece of steel plate to cut slots, or non-beveled or non-radiused grooves.

3) What type of endmill is good to start with for steel, and do the same tools usually work with aluminum. HSS, Cobalt etc.. Should I invest is a coolant system, and will certain tools cut better with coolant.

I am just looking for a place to start so any advice, recommendations, etc will be a huge help. I have a limited budget so I can't afford to be breaking tools alot, nor buying a huge assortment of sizes. I am new to this, so if possible go easy on me!

-Kory

 

[Rbeckett]

I would look into a face mill for the long flat cuts because it has multiple teeth in the cut and will remove a fair amount of material quickly and leave a nice flat surface finish. for plunging I would use an end mill of the same or very close size to the finished sole as I could. Since I do not know how large you need your holes I cannot even venture a guess. The smaller machines generally do not like anything larger than a 3/4 end mills and 3 inch face mills due to limited rigidity and lack of horsepower. A fly cutter may also be a viable option if the cuts are just long flat cuts removing material followed by a chamfer type of bit to achieve your required radiuses. There are many many ways to skin the cat limited only by your creativity, imagination and budget. I would look into a fly cutter since they are pretty cheap, you can even make one for the price of your time and effort if you decide that's the way to go. A face Mill from GMT would be kind of pricy but it has replaceable carbide inserts that you can replace and change for various materials and operations. HSS bits are good for steel and Alli but to get the best surface finish and material removal you should take the time to learn about hand grinding your own bits to adjust your relief and cutter angles to maximize your bits cutting and machines power. There is a sticky about that on this site and Tubal Cain (MrPete222 on you tube) does a great job explaining how to hand grind your own bits and what the angles all mean. In the smaller machines I prefer to use HSS tooling because I cannot get the high speed, depth of cut and feed rates that a high dollar carbide bit is capable of sustaining. Our machines just don't have enough horse power and rigidity to do that kind of work unfortunately. Sorry to muddy the water with so many other options, but there are many that you have not considered that will do a fine job. Hope this helps somehow. And welcome to the group, I have been absent for a while and unable to be as helpful as I would like but I am back now on a more active basis.

Bob

PS. A coolant system is always a nice thing t have since it will reduce heat and lubricate the bits as well as prolong their lives. But flood coolant does require a system to manage it all. They are all easily constructed with relatively cheap parts so it may be worth looking in to. there are also less messy mist systems that will work nicely too.

 

[negatronix]

Thanks for the reply! Most of the cutting will be along the edges of the plate to create the desired shape... very little face surface removed. I figured a fly cutter might suffice for very light surfacing. I will also need to bevel or radius the edges, and chamfer any holes.

I will look into learning about sharpening tools, that seems to be a huge factor in machining.

Fortunately, most of what I am aiming to do early on does not require a monumental degree of accuracy, nor brilliant luster as most of it will end up powder coated. I was doing a bit of this with a bandsaw and a drillpress... really ugly and too rough!! Time to take it up a notch!