Most Productive Way To Mill Shaft

Jubil

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Can someone tell me the most productive way to mill flats on shafts up to 3" diameter? Flats will be up to half the diameter of the shaft.
What type cutter, HSS or indexible. What size? I have Mills from 1 HP to 2 HP vertical and 3 HP horizontal.
Thanks in advance
 
For a flat that big, I'd be inclined to cut most of it away with a horizontal or portable bandsaw, then mill it to the finished dimension. I'd probably lean toward the horizontal mill for the finish.
 
I would think a plain or slab cutter on the horizontal mill. You don't say how long the shafts are. If they are short enough you could do it in one go.
 
I would suggest using something else to remove the bulk of the metal, and use the mill to finish up. It should go much faster and puts a lot less wear on your milling tool.

And in general, you want to [if the job permits] remove chucks of metal with a relatively cheap cutter instead of reducing said chunk slowly into tiny bits.
 
If you can't bandsaw the biggest part of it out try a cobalt roughing endmill.
 
Thanks guys,
What was I thinking? Band saw really makes sense.
I have used cemented carbide, carbide indexable, and hss, but not cobalt. Are they (cobalt) noticeably better cutters? I hope to be cutting several shafts and I'm looking at the time involved.
 
I usually go with cobalt roughing endmills because of the price compared to carbide ones.
 
How stiff is your horizontal mill? If it's a big one like a VN, Cinci or K&T then just clamp the work on the table and make the flats in 2 passes with a horizontal wheel. A horizontal with flood coolant can move some metal fast.
How about a shaper, do you have one hiding in a corner?
 
The best way is with the horizontal, as was said, if its rigid ie very heavy.
It will be very fast, and very accurate, one setup/go.
Passes will depend, maybe 2-3 or more at 3 hp, depending.

The 3hp indicates its not very heavy(maybe ?), but I would still plan for horizontal only.

A proper rougher is very efficient.
Use a modern one.
They can remove 3-5x more material / hp / time than old school stuff.

Which one ?
Depends.
A corncob type rougher in solid carbide is by far the best, if the cut /machine is suitable.
Ie given enough rigidity so it does not chatter, the corncob solid carbide will be fastest MRR, with best results, in least time.
It will be expensive.

You said 50% shaft, ie 3" width of cut.
Expensive. Might cost 500$. Or more.

A cobalt or HSS rougher may be 1/2 to 1/4 the cost.
So a small rougher might be best overall, and very much cheaper to replace.

Otoh..
A smaller endmill rougher, about 10-12 mm, would be the best option, imho, on modern high speed machines.
It would run at 10-20x faster feeds, and do many passes, much faster than a single large, heavy, expensive, rougher.

Maybe 300m-6000 rpm. TLAR method, just from people using them on more rigid stuff.

At 3000 rpm, on 300SFM, 0.5", 0.002 /teeth, 3 flute.
= 3000*.002 *3 = 18 "/min.

If the flat is 1" in length, it takes 20 secs to do, and 6 passes / depth at 0.5" endmill rougher D.

The *right* answer depends on machine, rougher, how many pieces, if $, time or production qty is more important.
The best answer with all data will still vary by more than 100%.
Ie with the best possible solution, someone can make it in half the time/cost.

Edit.
Possibly the best option.
Slit it with slitting saw. One pass. Cheap.
Then clean it with minimal cut using anything, a facemill or even a flycutter.
 
Wow, that's a lot of info.
My bandsaw is a HF. I doubt it would last very long cutting 2" or 3” shafts. So it looks like a cobalt rougher on my K&T No 2. ( w/3 HP it's not very heavy) with several passes. High rpm on this maçhine is 1350.
Thanks again.
I'm so new to machine work, I don't even know what a shaper is. Just recently found out what EDM is.
 
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