Eating up TiN cated HSS endmills need helP!

I would say that being a noob,it is a given that cutters will be broken / burnt / dulled.At least it happens that way for me.Depending on your machine,sometime you have to wing it.My mill/drill will only turn a little over 2000 rpm so I can't match some of the charted speeds.
 
Inflight said:
Coolant makes a huge difference.

Try the brown sulphurized cutting oil applied with an acid brush or a cool-mist #77 solution applied with a spray bottle.


Matt
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Cutting oil is NOT coolant - it doesn't have the right thermal properties (heat conduction and heat capacity),
Much as I hate anything water-based around machines, soluble oils and water (suds) is coolant! Cool mist comes a close second, the airflow does the cooling, the oil mist lubricates the cutter to avoid chip welding, the.air (or a flood of suds) also helps clear the.chips (which cutting oil, particularly heavy brown sulphurised, just sticks to the cutter...if using coolmist, use it as intended with a.decent supply.of.compressed air!

Also... I THINK 100 sfm is on the very high side for HSS in an unknown steel, drop that to 50-60 or.even lower if the work's a decent alloy steel, in my experience the t-slot nuts supplied with QCTPs are pretty damn hard and.need either annealing or carbide tooling!
Remember that with lower cutter rpm comes a proportionately lower feed, a chip load of 3-10 thou" per tooth per rev is in the.ballpark - so if you're running a 4-tooth endmill at e.g. 500 rpm, your feed should be between 6 and 20 (absolute max, probably too fast) inches per MINUTE, not per second!
The sfm figures given in the.Machinery's Handbook are for industrial machines in industrial settings -.rigid, plenary of power, flood coolant, and industry considers cutters as DISPOSABLE!
 
The cuts the OP are making don't require coolant if done properly. I've done more aggressive cuts with only brushed on cutting fluid. Of course that's me. YMMV...

And while I may have used up a end mill too fast early on, I've never burned one. Maybe it's because I spent a lot of time just watching my friend on his BP clone before I ever touched the handles. Guess I was fortunate in that regard.

Oh, and all that book stuff doesn't translate well to a machine that can be flexed several thou back and forth simply by grabbing the head and pushing/pulling on it. Best way is to start slow and work you way into this and learning what different types and cutter materials do what in what kind of metal. There are no shortcuts IMO.

Just my $0.02
 
I agree Bill, the speeds and feeds in the books are intended for heavy industrial machines, not hobby machines 10,000 pounds and 15 hp, not 100 pounds and a half hp! To quote Clint, "A man's gotta know his limitations"
I'm still saving pennies (and looking for space) to buy a mill (industrial size) so I'm limited to milling ;n my lathe:4500 pounds, 3hp, but still reduced cutting loads, it's not the job it's built for....

I agree your point about far-eastern flexy machines, I worked for a while at an importer and they were crap, I still don't understand buying one for more than an older, industrial mill or lathe!
 
British Steel said:
I agree Bill, the speeds and feeds in the books are intended for heavy industrial machines, not hobby machines 10,000 pounds and 15 hp, not 100 pounds and a half hp! To quote Clint, "A man's gotta know his limitations"
I'm still saving pennies (and looking for space) to buy a mill (industrial size) so I'm limited to milling ;n my lathe:4500 pounds, 3hp, but still reduced cutting loads, it's not the job it's built for....

I agree your point about far-eastern flexy machines, I worked for a while at an importer and they were crap, I still don't understand buying one for more than an older, industrial mill or lathe!
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I was only pointing out that these machines need a slightly different perspective than their larger brethren. I know, I have three currently, with more to come. :)

Many here, myself included (but speaking only for myself), have no room and/or desire for a 2 ton or larger piece of iron. At any price. We simply don't work on anything that requires something that large. And not everything a hobbyist does warrant such a monster. Does a watchmaker need or want a 5000 lb lathe? Hardly. To say that everyone who wants a machine needs the biggest they can buy may not be accurate for their situation. But other people do. Experiences/situations vary.

I have done some very accurate work on these small(er) machines. But the machine itself, because of it's limitations, requires some latitude in it's operation to get those results. It pretty much always comes down to the operator, not the machine. I was just trying to tell the OP that this is a learned skill on these machines and not something you can just get out of a book is all. Start small/slow and grow. You can be surprised at the results.

I am a avid golfer and one of my favorite quotes is: "the secret is in the dirt". I apply that to this hobby as "the secret is in the chips". You have to play to get proficient.

Again to the OP: Just back off a bit and take it a little slower. You may be surprised at the results. :)
 
I just like to give a guy some idea of where to start. I know for my self if I read take lite cut I think less then .010. When I read slow speed I think 300 and down. And thats completely relative to the dude reading it. I totaly discounted alot of bench mills because I kept reading "just take lite cuts" so to me that means that machine can only do .01 at a pass with no stress. And thats a huge misconception but thats my interpretation of the term. This is also why I ask so often what DOC their machine is pulling off with a typical end mill. Not a rougher. Thats important to me if I am buying. Because the terms used are so wide open to ones own conclusions.

That being said, the machine will talk to you, the material and cutter talk, shoot even the coolant or cutting fluid could say something. If you cant hold the part for 10min cause it will burn you that part is talking to you ahahahahahahaha
 
Yep, and horses for courses! I suppose my preference for industrial machines is down to learning on them (initially Colchester Students) and the fact my models are 12" to the foot (motorcycles...) - I did a.stint on a myford super 7 when I was in a prototype Lab, nice for its intended purpose but very limited because of size! My current lathe has about the same work envelope as.a.Chinese 13x30, but weighs about three times as much, is much easier to use with micrometer stops that trip the power feeds, quick-retract cross-slide, taper attachment, speed.changes on the fly, and cost less than a new Chinese minilathe - it did require work to run it from 240 single phase (hacking a VFD) though, and I admit it has a Big footprint, but the finish and accuracy are worth it? I have run out of room though, a couple of times, like making a longer pillar for my drill to allow for larger work... I've put my name down at work for when it's Big Brother (Holbrook H17, 60" between centres, 10hp, 11,000 pounds of English Iron) gets retired...

But yes, to the OP, slow down, you're not in a production shop so you can take your time :)
 
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