What have I got here?

[cessna]

Hi, I purchased a new bigger mill last week, it came with a large fly cutter with several carbide cutters brazed on, I decided to try it out on a piece of unknown steel 4" by 3". It did cut it using shallow cuts however while cutting there was a shower of sparks with or without coolant. Can anyone shed light on what type of steel I have here? It seems to be very hard.
Thanks
Terry

 

[aonemarine]

could be a speed and feed issue..pics of the chips and steel would help....along with pics of the cutter

 

[barnesrickw]

Some carbide like c2 is for softer metals like aluminum and brass. C5 and C6 are for harder steels. Also I think cast will spark from cast iron. Never tried it, so I don't know.


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[Chiptosser]

There a lot of varibles to what your cutter could be intended for.

First a picture, will tell a lot about the tool. I am trying to invision a brazed fly cutter, not seen one for years. The shape and orentation of the carbide tells a lot about the tool. What diameter is it?, what rpm where you spinning it?, how fast where you feeding?
Carbide doesn't like interrupdted cuts, like going over holes or irregular loading. What was your depth of cut?, .010, .050, makes a difference with the type of carbide and the shape of cutting edge.

Usually, if you see sparks, your cutter is dull, unless you are over speeding and taking a few thous., but if you are doing that, your going to have a dull
tool after doing that. Why?, carbide does not like to be over heated by rubing, which generates heat., causes the carbide cutting edge to form cracks. Yes, carbide can endure a lot of heat, but you have to know the limit of the tool that you are using.

Good luck

 

[cessna]

Thanks for the replies, the cutter seems to be the problem, I can cut it fine with a hss 3/8" end mill. The face mill that came with the machine is about 2 1/2" in diameter, I took a couple of pictures hopefully I can include.

 

[Tin Falcon]

Apples to apples the 2.5 in mill should be run at about 1/7th the speed of the smaller mill . but since carbide likes speed try reducing rpm by 1/3 or 1/2 and see how that works.
Tin

 

[Walltoddj]

It's hard to tell but looks like cutting edge is shot once carbide gets a little dull I get sparks all the time. At the price of inserts if it's still giving me a good finish I run them till they die as lot as it doesn't hurt the holder. I cut a lot of 4140ht so it works for me.
Looks like you'll need Bill's cutter grinder to sharpen that cutter are they brazed to the holder?

Todd

 

[Chiptosser]

It looks like you need to find a diamond wheel. The inserts show that they have been hot. And the leading edge on the carbides are dull, and chipped.
Your machine may not be rigid enough to prevent vibration.

Vibration kills carbide!

 

[deverett]

Hi, I purchased a new bigger mill last week, it came with a large fly cutter with several carbide cutters brazed on, I decided to try it out on a piece of unknown steel 4" by 3". It did cut it using shallow cuts however while cutting there was a shower of sparks with or without coolant. Can anyone shed light on what type of steel I have here? It seems to be very hard.
Thanks
Terry

One other thing... I was always given to understand that carbide should be run dry unless using flood cooling. The occasional spray or whatever that a lot of us hobbyists use will not do your carbide tis any good.

Dave
The Emerald Isle

 

[cessna]

Thanks again for the help, I seem to have a lot to learn about face mills and their use, I have used fly cutters on Sherline equip but never anything bigger.
Terry

 

[Swifty]

Another problem that I can see, is that unless you have a fixture for resharpening, the teeth will be at different heights. This will mean that there is a chance of only one tooth doing most of the work.

I have a single point flycutter that I have used for years on tool steel as well as brass and aluminium, I regrind when necessary, but the same tip still has a lot of life yet.

Paul.

 

[Walltoddj]

One other thing... I was always given to understand that carbide should be run dry unless using flood cooling. The occasional spray or whatever that a lot of us hobbyists use will not do your carbide tis any good.



Dave

The Emerald Isle

That's a misconception carbide if sprayed or oil is used on the part is fine IF you do this from the start. Carbide dry gets hot and grows as you cut if you run it dry it's best to take half the cut to warm the cutter then measure the finished end to make your finish cut. We used a 6" mill in P20 at .250 deep the chips were as big as your thumb and we would shovel them in to a steel dumpster you didn't want them to touch you and yes we did have sparks from time to time.

Tod



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