OK, that wasn't so bad. Didn't really want those old 1/4" endmills anyway.
They proved to be a little light for .375 steel plate. 3/8" endmill worked much better.
 I decided to run these 1 at a time and used the same basic method Terry mentioned, I didn't want to risk scrapping 6 per setup. Glad I did ! 
Held the stock in the vise and put a clamp on the part so I could run a finish pass. Then flip and repeat.
They came out better than I expected. Even the hole is almost acceptable but will ream them anyway.

Perhaps you could help me with the feed, speed and depth of cut.
The rpm dial on the head is pretty well hosed so I'm just guessing at the actual rpm. I do have a handheld digital tach that I can use until I get an index pulse to Mach.
Using a 3/8" (9.5mm ), 4 flute, HSS endmill.
No coolant hooked up yet, VERY soon though. Just a spray bottle w/ soluble mix for now.
I ran these , DOC .100" and tweaked the rpm and fr ( 2 to 6 ipm ) as I went along trying to get it done as quick as possible.
What would you guys recommend as a starting point ?
DOC
RPM
FR
Thanks

Russ,
This link can calc what your asking.

http://www.custompartnet.com/calculator/milling-speed-and-feed

There are other sites as well. I usualy just use the info  or charts that are in Cleveland Twist Drill / end mill technical section. It provides a good table for chip load to rpm and is easy to use.
Sometimes nothing beats the good old paper sheet in hand.

RICH

Thanks RIch, the info you posted reflect pretty much what I see elsewhere.
It all seems soooooo fast to me , just looking at the #".
I'll just tinker with it. Thank goodness there's a sale on endmills this week.
Beginning to think my .100" depth is too great.
See ya.

Hi Russ,

Looks good.

If machine rigidity is not a problem, these end mills should do fine up to depth of 1/2 their diameter cutting full width.

If you can get a deal on some roughing end mills it would save you some money on the finishing ones which you want to keep sharp. Also roughing end mills can go as deep as their diameter on a full width cut. Carbide are best and are a good investment, especially when you have no coolant.

Dan

Thanks Dan,
 How about the chips ... will they destroy a carbide cutter if they are not blown clear of the slot ?
I'm thinking of getting a mist type deal with just enough air to keep the chips outta the slot but not blow them all over the shop.
Anxious to try the carbide.
See Ya,
Russ

Russ,

Good evacuation of chips is certainly desirable. I haven't investigated how they effect the tool life, but they sure cause an awful noise if not evacuated to clear the cut. Just hearing that noise makes you think it's going to break the cutter, so haven't had the courage to leave it like this for more than a few seconds

Dan

I've always seen it as a must to get the chips out, especially with carbide, because they have a tendancy to chip. Once they start chipping/fracturing, it goes downhil fast.

I do most of this kind of work manually, and depending on the size of the job, I just use a handheld blowgun with quick blasts of air, or set up a mister without the coolant to keep the chips out. Unfortunately, this throws chips everywhere as we do not have enclsures around our mill. Whatcha gonna do 

Dave

I did hold my blow gun at the cutter with just enough to clear the dry chips and it took surprising little velocity/vol to keep it cleared. Didn't make much mess at all.
No encl here either. Maybe on next mill tho.
Dry air with carbide will be my next attempt, then maybe mist.
Tanks Dave.

York this year ? 

I use a a shop vac to take the chips away along with a cutting fluid ( hand sprayed / too lazy to add a drip nozzle ). Nothing auto in my hobby shop.
Don't like the air spray since the chips go all over the place and not good fom a safety point of view ( they would fire you if you did that at the company shops ).

The roughing end mills are great for fast material removal especialy in Al.

Over time i have read a number of technical books on milling. Cincinnati Milacron had a book alll about the testing they did with end mills and the SME continues to research
with member companies. That said, there has been advances in tooling etc and a lot of the companies have tech info. After a while you find it's just automated in a some program and refined
particular info is presented. Same basic rules with the clarifier to adjust based on testing of your machine, material, etc.

Thus i am attaching copy from Cleveland tech section on end mills as the info is still good.
See page 6....pick the material and look at the recomended feed chip load for size of end mill, and get spindle rpm range.
Use the other info to adjust and easy calc to get you in the ball park.


I actauly did a spread sheet for the Atlas Mill based on available spindle speeds fly outs of info, and does all the calc's
( never use it ....easier to look at the tables ).

Carbide is great, but watch it as you can break them easier than say cobalt end mills. Backlash can kill one on a deep cut .


from the hobbiest FWIW,
RICH

 

Just to add up to what Rich and Dave said about carbide end mills. Avoid hand spraying with carbide tools as the fast temperature drop may chip them.

Dan