I thought I would do a follow up since I got a lot of advise on using the indexable end mill.
I needed to square up a piece of 4140 for a project. Well the end mill worked wonderful I got a glass smooth finish with very little tool marks. I ran the tool at 1200 rpm conventional milling with a medium spray of coolant, the chips came off at a light brown. I only needed to take a couple of .025 cuts to square up the piece.
I am a happy miller
While insert mills that take APKT-style inserts are indeed capable of more abuse (and productivity) than TPG inserts, you can see from the OP's response that it works fine on a Bridgeport when care is taken.
I've got both, and both get used. The APKT-style one is a Valenite V590 B 10 075 WC 15. The AP10-size inserts can take quite a bit of abuse in any material I throw at it, but I especially reach for that one for stainless steels or for big material removal on carbon steels. It's a 3-insert cutter that can ramp into pockets pretty good too, though I don't do that often. I do know the cutter can take off more metal than the Bridgeport's motor can, any day.
For lighter cuts at slow feed rates, I have a no-name 3-insert 1-1/2" cutter like the Enco one (right hand though!) for which I have sharp uncoated inserts. It's great for aluminum & brass.
Well, as John said about Evan's indexable cutter:
"it can't not work well, it's a rotating tool"
TPG inserts are about 1/3 the price or less of the APKT style inserts so for hobbiest they are a much better deal. We use them at work, at home I use TPG's due to cost.
Originally Posted by PaulT
The true cost of expendable tooling lies not in the initial outlay of cash, but in the cost per part. While true a TPG insert isn't as expensive per edge as most APKT form inserts, their productivity pales in comparison. How many edges and how much time is spent with one vs. the other? At home we have the luxury of time (but not always) so we often overlook true cost per edge.
Originally Posted by Mcruff
I agree 100% with PixMan on this issue. I get much better performance, tool life and quality of cut with APKT based endmills than I did with my original TPG based ones, so although the APKT inserts cost a little more they are cheaper in the long run. You can also get them pretty cheap from www.latheinserts.com and www.carbidedepot.com .
I find the same thing is true on lathe inserts. While CCMT inserts cost more and only have 2 cutting edges, their performance and lifetime is so much better that I put all my old TPG lathe tooling away.
At work everytime we change out our APTK cutter it cost $200, hobbiest would have a hard time outfitting that the 1st time let alone changing it. When you can buy TPG inserts for $2 an insert its at least useable and you can spread that cost out over a long while even if it doesn't last as long. If you crash it you lost $6 in inserts the other one you usally lose at least $40 and could be as high as $80 (hobbiest not pro), alot of money for a hobbiest. I use this stuff for a living so I know what you mean but guys using it at home generally don't have the budget for that kind of tooling.
If you don't mind radii get rid of the APTK inserts and go for the round ones such as RCMT, they will give tons of edges and will cut about 10x the cubic inches of material that the other ones do and at a much much lower cost.
Well of course it makes no sense for a hobbiest to be replacing a mill body for $200.
And it's not economical for a shop owner either. While accidents happen, why is it more acceptable if it's a "shop tool" at work? I've never understood that thinking. I treat every tool as though it were my own (and nowadays, most of them are.)
I got my Valenite V590 cutter brand new in a kit with 10 inserts for $65 on Ebay. I look for deals like that and now have tools for dad's home shop that are as good as anything "they use at work." I figured if it's good enough to make money with, it's good enough for me.
There are incredible deals on Ebay for quality name-brand tools at really cheap prices, especially turning inserts. Since I educated myself about them and know what I'm looking at, it's been amazing how cheap I can get the tools I need for the home shop. Why blow $10 on a scratch-off ticket if I can get 10 good CNMG432 turning inserts? I have a lifetime supply for about $30, and grades for all materials. The shop owner usually doesn't have time to go hunting Ebay like I do though. The only thing to watch out for is getting into an obsolete milling cutter that you won't be able to get inserts for.
What to do!
The fly cutter is a good tool and definately has its place in the home shop environment. If one is transitioning to indexable insert milling cutters take a step upward and go to the state of the art not something three generations of cutters back. Try some of the Glacern products they all work good and are fairly priced. They support this site with their advertising and I appreciate that.
I didn't say mill body I said inserts. Our inserts for our tool at work cost $20 an insert, 10 on the tool, our company wouldn't use ebay even if they could, the place is to large and they haven't got time to search ebay for a deal. When a CNC is running and 1 insert breaks for one reason or another you have about 3-5 seconds before a total melt down occurs, catch it in time its only inserts go more than about 10 secnds and the tool is garbage. We have lost several $300-$500 tools in the last 6 years for one reason or another, never an operator error. Last week I cut 900lbs of steel chips from some large parts we were making in 2 days (24 hours). I can't afford the luxury of time when I have to do it, I can afford to push the tools like they should be and if a tool goes down and is tore up I have a replacement, its cheaper than the job being late.. The boss and the company expect it. As far as taking care of tools, I take better care of the tools than 99% of the people out there. I have been in this business for 30 years now, 7 1/2 of it I owned my own shop and built high end plastic injection molds. I am quite capable of taking good care of whatever I am using but crap happens. Hell my drill index is 30 years old and I have only replaced maybe 15 drills in it, they have drilled 10's of thousands of holes in that time.
Originally Posted by PixMan
As I stated earlier cost is a big issue for home guys, my TPG's at home last a long time cause I don't push them hard on a bridgeport. My lathe inserts I bought are tpmg's bought about 5 years ago, I have used 2 inserts out of the 20 I bought, the machine is used constantly. If you can find more modern insertable endmills for a good price and inserts to match go for, but don't condemn these guys for using older proven styles because of cost and inexperience issues. The TPG units are so common and cheap its pitiful and that has a lot to do with why they sell so many, there trusted, proven and reasonably cost effective.
Last edited by Mcruff; 02-14-2010 at 09:55 AM.