Milling lesson

That depends. If you are using just one side to face the edge of a workpiece, then four flutes doubles the number of "teeth", so the feed per tooth can be doubled for a given RPM and workpiece material/cutter material combination.

O.K. And as someone else mentioned, are you locking the axis which you don't want to move? Vibration can cause the handwheel to rotate, especially if it is not a balanced handwheel (extra mass on the side opposite the crank handle, so it will balance in any position).

Hmm ... I would use something like Rigid's high sulfur threading oil in preference to that for that particular task.

And an alternative possibility is simply a jet of compressed air directed right at the cut to blow chips clear so they can't build up on the cutter and bind it in the cut.

O.K. With a 1/4" end mill, your top speed puts you at 71.99 SFM, which is probably not bad with a mild steel and a *good* HSS milling cutter.

Yes -- when your RPM is an unknown, yes, you don't know what you have even if you know your IPM (inches per minute) based on how fast you are cranking the leadscrew. (Of course, in the machines where it really matters, the spindle is geared to the table feed, so it is truly a feed per tooth, even if the spindle loads down a bit -- so does the feed.) And in CNC, it is computer determined.

And with key stock, it is more the gummyness of the steel, not the hardness. I believe that key stock is low enough carbon so you can't harden it.

But yes -- if you had hardened steel, the speeds have to be reduced.

And the shaking could cause the other axis to feed if it is not locked. Does your machine have locks for each axis?

:-) Read the posting by Teenut (archived somewhere that someone will surely point out) discussing how a real machinist sets the feed on a machine in production. (The basic idea is to start cranking until you feel uncomfortable about the machine's behavior, back off a little, and then bring the power feed up until you feel it catch up with your cranking. :-)

For slot milling, at least. For a lot of other things, four flutes is a better choice. Slots are a special case.

Good Luck, DoN.

Reply to
DoN. Nichols
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Yes. The one that I forgot most frequently was 'z', but few disasters cured me of that .

Great minds think alike...

I shall have both. They should be on their way as we speak. A unexpected benefit of the whole episode was that while studying catalogs for the mills I found a digital indicator on sale for Cdn $40. I could not resist it. My Taig will thank me. I got them to throw it in the bag with the mills.

Reply to
Michael Koblic

I found that coolant/lubricant and ease of chip removal are mutually exclusive. I find it hard to get the chips out with a shopvac *after* I finshed milling. The best I find is what someone else suggested and that is blasting the chips out by compressed air. They of course end up in other undesirable places.

Having said that I find it difficult to believe that chip removal is the

*main* cause of the phenomenon described in a 0.050" slot.
Reply to
Michael Koblic

I think I pretty much demonstrated that. I was surprised that the effect is apparent in slots as short as 0.050".

Speed? - almost

I tried that, but for some reason the mounting holes on the top part of the viseare just enough off so the vise cannot be mounted parallel.

E-type collet.

Have you set up the mill properly (or at

Yes.

The belt drive conversion helps

So far no evidence of that. Belt conversion is the next thing if there is any doubt about the state of the gears.

Or I can take up knitting...

Reply to
Michael Koblic

Yes, you could take up knitting - no doubt there are knitting groups you could argue with too. You have been given good advice, try some of it out. You have an X2, and a lot of really good work is done on them by people who work within the limitations of the machine. For what your doing, it would be quicker and easier (for you) if you drilled it out as much as possible and then used a file - a technique used before milling machines were invented. If you can, enroll in a trade course - that way, you will have enough knowledge to know if its your own limitations or the machines.....

Andrew VK3BFA.

Reply to
Andrew VK3BFA

Faaaaarrrrkkk! - Gunner, you still have the capacity to blow me away sometimes - thank you - a lot of what I have learnt is from this group, even the political Neanderthals....... Andrew VK3BFA.

Reply to
Andrew VK3BFA

......................

1) You cannot legislate the poor into prosperity by legislating the wealthy out of prosperity.

2) What one person receives without working for, another person must work for, without receiving.

3) The government cannot give to anybody anything that the govern- ment does not first take from somebody else.

4) When half of the people get the idea that they do not have to work because the other half is going to take care of them, and when the other half gets the idea that it does no good to work because somebody else is going to get what they work for, that my dear friend, is the beginning of the end of any nation.

5) You cannot multiply wealth by dividing it.

- Adrian Rogers, 1931

Reply to
Jim Wilkins

That would be a 'DE9' cutout, even though a lot of people use the wrong name. The second letter is the shell size.

Reply to
Michael A. Terrell

Right. Forgot you can lock X *and* Y this way. Maybe I won't even have to use the fine feed this way.

Got it! The centre line is the reference. Makes sense.

.

I try to use dial indicators whenever possible. I guess backlash comes into it even on the near side, depending where one left the wheel to start with.

Now I understand it. Thanks.

Yes. I might even discover what these quills and tables going up and down are all about....:-)

Reply to
Michael Koblic

Quill? Raise the table? What are these wondrous things you speak of...:-)

Do you do this with 2-flutes or 4-flutes?

I now have 3 different ways to do the same job. It will be interesting one day to do another comparison run. I shall try to design it so the measurements are more meaningful.

Thanks.

Reply to
Michael Koblic

Here is some basic reading on the subject:

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However for your machine, technique is usually going to be the biggest factor in the selection of the number of flutes, so I would keep it kind of simple. Select a two flute if you need it to cut in the center, other wise a

4 flute should work just fine.

The number of flutes and teh geometry of the flutes gets really critical when you are talking high speed production runs and the like but it is not going to be much of an issue for you.

One important factor is going to be the length so use the shortest length you can for greater rigidity.

Reply to
Roger Shoaf

You have a Sieg X2, right?

The quill feed makes a mill handier as a drill press but on an old worn machine like mine it's an extra wear surface contributing to inaccuracy. In geometric terms your single dovetailed Z axis should be more precise and rigid. I suspect that with heavy production use it might wear faster than a quill plus a knee supported at its center of gravity. Unless you need to duplicate complicated broken machine parts you may have a better hobby mill.

The Clausing has too many adjustment joints to be solid enough for heavy cuts. You can see them in use here,

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Like a Shopsmith or my Toolmaker surface grinder, each additional degree of freedom that increases versatility also decreases stiffness.

jsw

Reply to
Jim Wilkins

At work, whatever is still sharp. I'm an electronic tech and don't usually get the big jobs so what milling I do there is more like light hobby work. At that level feed and depth of cut have more effect than the number of flutes. I speed up the crank until the tool or machine starts to complain, then back off. On that lot of plastic boxes for in- house test use the slots were only for clearance so I pushed the cut to see what would happen.

I think the idea is to make each cutting edge take a healthy bite because edges wear more from distance travelled than thickness removed, then have enough flute spacing for the chip produced. In practice there isn't that much difference between 2 and 4 or the 8 flutes on my shell mill, they all work well with the right feed, speed and depth of cut.

jsw

Reply to
Jim Wilkins

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Like a Shopsmith or my Toolmaker surface grinder, each additional

Not if they are tightened before starting a cut.

Btw..I have an 8540 horizontal Clausing mill for sale..in decent shape if anyone is interested. Ill even toss in some tooling, arbors etc etc.

Gunner

"Lenin called them "useful idiots," those people living in liberal democracies who by giving moral and material support to a totalitarian ideology in effect were braiding the rope that would hang them. Why people who enjoyed freedom and prosperity worked passionately to destroy both is a fascinating question, one still with us today. Now the useful idiots can be found in the chorus of appeasement, reflexive anti-Americanism, and sentimental idealism trying to inhibit the necessary responses to another freedom-hating ideology, radical Islam"

Bruce C. Thornton, a professor of Classics at American University of Cal State Fresno

Reply to
Gunner Asch

The X2 is what it is. Looking in Grizzly catalog the shipping weight is 149 lbs. The next one up (X3??) is 418 lb. Putting an indicator on a mag base on the table with the point against the column (not the spindle or head, just the column) about 2/3 up I can make it flex 0.020" in both directions.

I do not know how it compares with anything else (which, in a sense, is why I started this thread in the first place) but I suspect that the difference will be significant even against the X3.

I know that people pour concrete into their column and devised all kinds of brackets to strengthen it - I am not sure if that amounts to flogging a dead horse.

At this point it does not matter too much as few thou either way are not kill me. If it ever becomes an issue one will probably consider an upgrade.

Reply to
Michael Koblic

I really only have chatter problems with deep cuts with 2-flute end mills or large drill bits cutting pipe, with the knee all the way down for clearance. Then the dumbbell-shaped head and motor assembly twists back and forth. When tightening everything and reducing the feed don't help I drop to the lowest speed, which usually kills the resonance.

The head rotates 0.001" / 60 Lbs relative to the lowered and clamped table.

jsw

Reply to
Jim Wilkins

Filling the column with concrete will increase the weight and reduce chatter. If I were going to fill the column with concrete, I would include as much rebar as I could. Especially trying to have the rebar next to the wall of the column. That might increase the stiffness a noticeable amount.

=20 Dan

Reply to
dcaster

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