Carbide end mills

[kiwi2]

Hi,
I'm interested in trying some carbide end mills but I'm getting a bit confused. I've found some which are described as carbide end mills, but later are described as HSS (high speed steel?) with a AlTiN coating.
Are these carbide end mills?
I thought carbide meant they would be made of tungsten carbide.
Can anyone set me straight?
Thanks,
Alan

 

[stevehuckss396]

Carbide means carbide

HSS is High Speed Steel

AlTin is HSS coated with Aluminum Titanium Nitride

More information on coatings here: http://www.hannibalcarbide.com/technical-support/titanium-coatings.php

 

[BaronJ]

Hi Alan,

Depending on what I am machining, I will often use a carbide wood router bit. They work well on brasses and alloys, but you need to take more care on harder materials, steel and iron because the edges tend to chip more easily than the proper tip inserts.

One thing that you will find is that when using them on the mill the cutting angle is wrong for steel, so slow and steady...

 

[bazmak]

I bought 2 lots of end mills which were described as carbide
One set were good quality carbide,i think german.They are great
The others were HSS and don't last 2 minutes on M/st. Will try and stick to Carbide where possible in future

 

[Wizard69]

Hi,
I'm interested in trying some carbide end mills but I'm getting a bit confused. I've found some which are described as carbide end mills, but later are described as HSS (high speed steel?) with a AlTiN coating.
Are these carbide end mills?

When I think carbide end mills it is solid carbide. I would not do business with an operation that can't get that right. End mills that use carbide inserts are a different story though.

I thought carbide meant they would be made of tungsten carbide.
Can anyone set me straight?

I think previous poster covered it well, carbide end mills implies that the end mill is solid carbide. That carbide might or might not be costed with something. Consider carefully what sort of coating is actually on the end mill. Some coatings don't like aluminum for example.

Thanks,
Alan

It might help to say what you have in mind here. Sometimes carbide isn't the best choice. The mills are brittle and can easily shatter or chip. You need to be very careful to make sure the end mill doesn't recut chips, especially in work hardening materials. Hard swarf will damage HSS of course but the damage done to carbide can be more extensive. You really want the provision to remove the swarf, either by flood coolant or an air blast.

In any event carbide has its good points but it isn't always the best choice for a particular task.

 

[bazmak]

When a lot of matl has to be removed from mild steel,i try to rough out the bulk with carbide then finish with light cuts with hss

 

[kiwi2]

Thanks all. That has sorted it out. What are your views on solid carbide cutters versus cutters that take inserts?
Speaking of high speed steel, there has been a bit of it turning up on the local auction site at low prices. I bought a couple of lengths and made a thread cutting tool out of a bit. I used it on a few aircraft bolts for a friend and found they went blunt very quickly. At first I put it down to aviation bolts being made from a hard alloy but then did a simple hardness test by trying to scratch it with a sharpened piece of an old HSS tool I had. It scored it with no trouble whereas the new material just skated across the surface of the old stuff.
Oh well, we live and learn. At least they are accurately ground and I can use them as parallels.

Regards,
Alan

 

[BaronJ]

Hi Alan,

I've only a couple of home made toolholders that use inserts. My preference is for HSS tool bits. There is however a lot of rubbish HSS about, and as you have discovered not worth buying. I must confess to not having bought any new HSS tool steel in many years, prefering to pick up old tool bits from the local scrap yard. Some of the stuff I've picked up has been marked with various brand names, all British made, some even has 6% cobalt marked on it.

Second hand and charity shops are also good places to look for old tooling.