I didn't break my 2mm endmill!

[Black Forest]

Today I tried for the first time to mill with a 2mm endmill. I didn't break it. Brass was the material and I really babied the feed rate. The webs between the "spokes are intentional. The are for a friend who likes spidery type motifs! I hate spiders.

[elf]

Try it with a 0.4mm endmill and if you get real crazy, they make 0.001" endmills

[Dave C]

Spiders are your friends. They catch a lot of bad bugs.

[old mart]

Babying the feed rate was exactly the way to go, and 10000rpm if your machine will get that fast. Think of the difference of size between that 2mm and what you are familiar with and reduce the rates in that ratio, then take off some for the smaller cutting edge speed. I buy boxes of 20 little solid carbide cutters of 3mm down to 2mm from China, very cheap, then if one breaks, there are no tears, and our mills best speed is only 3000rpm.

[gellfex]

Ughh, I have a repeating job that calls for a 3/32" slot in 6061, that's 2.38mm. I often get impatient and break em! A couple of years ago I took a flyer at a high speed head, but it didn't work out so well. I need to get a belt that doesn't stretch at high speed!

[Black Forest]

Ughh, I have a repeating job that calls for a 3/32" slot in 6061, that's 2.38mm. I often get impatient and break em! A couple of years ago I took a flyer at a high speed head, but it didn't work out so well. I need to get a belt that doesn't stretch at high speed!

I leaned back in my chair when the belt started growing! I didn't want to get hit in the face.

[gellfex]

I leaned back in my chair when the belt started growing! I didn't want to get hit in the face.

Good instincts there!

I don't know what belt to use, a mini V kept rolling over. I'm sure I'm not alone in having shelves full of half done projects!

Regarding using tiny end mills, I ended up making a mount for my Foredom flex shaft tool holder (that's the Foredom Motor in the rig) that strapped onto the quill. Worked great to get into that 10k range.

[Paul Alciatore]

Good job! And welcome to the club. Smaller can be a bigger challenge than larger.

I have a Unimat and it will do 2mm all day and be totally happy at it. I have used it for around 50 years and I can't remember breaking any small end mills. Anything above 1/4" or 6mm is a big cutter. Of course, it has the high spindle speeds, up to 10K, that make this easier.

As for the belts, the Unimat uses 1/4" O-ring style belts and they do belly out somewhat at the high speeds but they only rarely break. And when they do, there is little or no danger to the operator. They just flop down in place.

[RB211]

First time with my CNC mill, I must of snapped 10 carbide end mills

[Black Forest]

First time with my CNC mill, I must of snapped 10 carbide end mills

I am always amazed at how much abuse solid carbide end mills can take! I have broken a few but not nearly as many as I thought I would.

[RB211]

I am always amazed at how much abuse solid carbide end mills can take! I have broken a few but not nearly as many as I thought I would.

You are probably using 3/8th size and larger, I'm around 1/8th with the bench top CNC.

[Black Forest]

You are probably using 3/8th size and larger, I'm around 1/8th with the bench top CNC.

Yes, until now the smallest I have used was 6mm. Watching this 2mm mill with three flutes chomp through some brass was quite cool to watch. I know simple things amuse simple minds.

[gellfex]

As for the belts, the Unimat uses 1/4" O-ring style belts and they do belly out somewhat at the high speeds but they only rarely break. And when they do, there is little or no danger to the operator. They just flop down in place.

Do they belly as much as the urethane one on mine? Should I not worry about it?

[DR]

I had to drill five .020" diameter through holes in a row in 3/4" thick copper. If any of the holes were bad the part was ruined.

Interesting customer, medical patient monitoring equipment and I went to engineering school with my customer contact. He was a wannabie machinist so he insisted on telling me how to do jobs and supplied the tooling. Fine with me. Using my smallest CNC mill I wanted to hold the drill in an ER25 collet. That size is not made so the guy had a couple custom made, must have been expensive.

We had problems with regular copper. He applied to the FDA to allow us to use tellurium copper which is slightly radioactive but machines much better.

Peck drilling in small increments with flood coolant with a slight pause as the drill re-tracked between pecks. The pause was enough time to use a fine brush to make sure no debris was left on the drill flutes when they pecked. The part was to pump "body fluid" through for cooling. In all the years I worked on medical equipment customers always said body fluid instead of blood.

[Superbowl]

Ughh, I have a repeating job that calls for a 3/32" slot in 6061, that's 2.38mm. I often get impatient and break em! A couple of years ago I took a flyer at a high speed head, but it didn't work out so well. I need to get a belt that doesn't stretch at high speed!

Can you use a 3/32 slitting saw instead of an end mill?