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O2
06-18-2005, 01:03 AM
Hello. I've got a real newbie question for you all. How do you go about milling a slot? I've got a HF44991 mill. I'm trying to mill a 3/16" slot in a piece of brass. The slot needs to be about 3/8" deep and anywhere from 3-5" long. I've tried with varying degrees of success, but none quite right. I've tried to plunge to the depth I need with a center cutting mill and then slow feeding the cutter at the full depth of the cut (if that makes sense) but I got a lot of chatter. So I tried to slow the speed down to about 500 rpm and speed up the feed, and that didn't work so well either. Lots of chatter and a lot of ridges in the cut. Then I tried to mill the slot in cuts of about 1/16" at a time but the bottom of the slot was offset a little, like 1/32" or so. In the machine shop trade secrets book the author said to mill a slot with an undersize mill, then go back with an on size mill, so I tried that and ended up with a broken 1/8" mill.

Any suggestions? I know that the HF desktop mill probably isn't the best unit, but it fit in my budget, both price wise (My mom got it for me as a gift) and size wise (I live in an apartment) I am using a 2-7/8" screwless precision vise I got from enco and my mills are 4 flute hss. I also ordered a couple of 2 flute mill to see if that helps, but I haven't had the chance to use them yet.

Also, can anyone recomend a basic book on using a mill? I've bought several books lately hoping to find some good info, but I don't really have anything on just basic use of a mill. Theres lots on lathes, but not a whole lot on mills. The machine shop trade secrets book has been the most usefull, but its more geared to pro's, so there isn't anything in there for a rank beginner like me.

Alistair Hosie
06-18-2005, 01:11 AM
You cannot use amill by drilling to appropriate depth and using it like a wood router even in wood you need to cut a little at a time same with metal try making sure everything is gripped tigh especially in the vice and take your time then make very light cuts and return to make more till required depth is met.Alistair

Norman Atkinson
06-18-2005, 01:16 AM
Milling cutters are not- repeat not designed for slotting. They are designed to surface an article.

A slot drill- is a slot drill!

A 3 page dissertation on the subject is available. Geo H Thomas writing in the Model Engineers Workshop Manual by Tee Publishing as follows

"Furthermore, the sides of the slot will be very rough, looking as though they have been nibbled away by rats"

When you get your slot drills, your speed should be 4000 rpm!

From one who has kept rats!

Norman

Evan
06-18-2005, 01:44 AM
Yes, you need a slot drill. It is two flute and the cutting edges of the flutes on the face do not meet at the center. This allows for plunge cutting.

This piece was milled with a slot drill using a milling setup in my lathe. Although it may look like the slot isn't the same depth all the way across it is, it's just the light.

http://vts.bc.ca/pics/test1.jpg



[This message has been edited by Evan (edited 06-18-2005).]

pgp001
06-18-2005, 02:43 AM
If at all possible I always try and use a horizontal saw type cutter for slotting.
Much better results can be obtained.

It all depends on what equipment you have available though.

Phil

O2
06-18-2005, 03:06 AM
Thanks for the quick replies. I had never heard of a slot drill, and I just did a quick google search to see what I could find. The first 5 pages of hits I checked didn't come up with a single US supplier I could order from. At least not that I could find. Any recomendations on where to find some? I also tried the usual places I order stuff from, like Enco and MSC and no go for them either.

Thanks for the help, I'm a total newb and I'm learning by doing and reading as much as I can.

Evan
06-18-2005, 03:09 AM
It is a UK term. I'm in Canada in a very small town in the west but I can get Dormer slot drills locally. Try someone that has Dormer products.

Stanko
06-18-2005, 03:57 AM
Are the gibs on your mill adjusted fairly tight? Does the table shake? if it does then you may need to tighten the gibs. it is an adjustable strip that runs in the dovetail that the table slides on ther is one for each axis. They are normally a screw that you adjust which pushes the gib strip in or out. the gib is tapered (normally) so that is how the slack is adjusted. Might not be the problem you have, but worth learning about if you want nice looking work.

JCHannum
06-18-2005, 07:35 AM
A two flute end mill is what the British refer to as a slot drill. A four flute end mill can also be used for slotting. Either a two flute or four flute can be used for plunge milling if they are center cutting. Most endmills sold these days are center cutting.

A 3/16" slot 3/8" deep is quite deep for the diameter, and the mill will flex if forced too much.

Get the speed up to 2000 RPM or better, if that is possible, and only cut about 0.050" or less depth at a time. Feed the table slowly. Make sure the gibs are tight, the table should feed smoothly with no side to side movement. Lock the table movement not being used and the height movement.

If it is a blind slot, it will be difficult to clear the chips, vacuum them out, or use low pressure air to remove them after each cut.

The same advice applies to the 1/8" mill, and it would be best to mill an undersize slot first and finish to final dimension with the 3/16".



[This message has been edited by JCHannum (edited 06-18-2005).]

j king
06-18-2005, 07:51 AM
JC is correct.Look at any endmill catalog and look for center cutting endmills.As stated,most are that way .

RobDee
06-18-2005, 08:39 AM
The best way to cut a long kerf is with a slitting saw. I only use end mills when I have a relatively short piece of work that must end abruptly and I cut no more then 1/10D of the cutter on each pass. So a .25 kerf would mean .025 depth of cut.
If you use an end mill use one with LESS diameter then your slot. Make your initial cut then clean up the remaining .005 or so on each side in a separate pass. This will give you the nicest cut.
On small machines don't do a 'climb' cut, most are not rigid enough.

larry_g
06-18-2005, 11:12 AM
02
Just a couple of questions here; Are you using a collet to hold your end mill or are you chucking the cutter in the drill chuck? Do you have every thing shortened up as much as possible? If your milling 3-5" and only have a 3" vise are you experiencing the part moving,vibrating, while outside of the vise jaws?
As for books doesn't Sherline or Taig have a micromachining book that is highly regarded. I've not read it but others have spoke of it.
lg
no neat sig line

O2
06-18-2005, 11:49 AM
Thanks for all the input. I've got a lot of learning to do. I haven't checked the gibs, but I've not really noticed any table shake at all. Its a good thing to know.

I am using collets with my mill, the first thing I did when I got it was take the chuck out and put it in a box.

I think that part of my problem is that my vise might not have been clamped to the table tight enough. I have more strap clamps now, so I'm going to add a couple and see how that works.

My machine can do 2500 rpm I think, so I'll turn it up and see how that does.

The most successful try so far did look like rats had nibbled the sides away. I want the sides smooth though.

I bought a slitting saw arbor and some blades and I thought to try that also, but one end of the slot is closed.

I picked up the desktop machining books from sherline and they seem to mostly be advertisements for their products. They do have some usefull info, but nothing on making slots.

Carl
06-18-2005, 12:06 PM
Everybody has pretty much abandoned the real answers to this question. Shapers and horizontal mills.

Evan
06-18-2005, 12:21 PM
A two flute slot drill is not a two flute end mill. The flutes on a slot drill are asymmetrical. This can be plainly seen in this photo of a Dormer 1/4 inch slot drill that I used to mill the above example. The slot drill and the end mill are not the same.

http://vts.bc.ca/pics/slotdrill.jpg

Evan
06-18-2005, 12:34 PM
It seems to me that those in the US are lacking access to a valuable bit of tooling.

It reminds me of the Robertson screw.

[This message has been edited by Evan (edited 06-18-2005).]

mochinist
06-18-2005, 02:07 PM
Evan do you have a better pic of that slot drill or a good link, I always wonder what you guys are talking about when you refer to slot drills.

mochinist
06-18-2005, 02:17 PM
<font face="Verdana, Arial" size="2">Originally posted by NORMAN ATKINSON:

Milling cutters are not- repeat not designed for slotting. They are designed to surface an article.

A slot drill- is a slot drill!

A 3 page dissertation on the subject is available. Geo H Thomas writing in the Model Engineers Workshop Manual by Tee Publishing as follows

"Furthermore, the sides of the slot will be very rough, looking as though they have been nibbled away by rats"

When you get your slot drills, your speed should be 4000 rpm!

From one who has kept rats!

Norman</font>

Bull I have made thousand's of slots with endmills and they look just fine.

mochinist
06-18-2005, 02:22 PM
<font face="Verdana, Arial" size="2">Originally posted by Carl:
Everybody has pretty much abandoned the real answers to this question. Shapers and horizontal mills.</font>


So you are saying the guy should go buy a shaper and a horizontal mill and put it in his apartment?

Evan
06-18-2005, 02:40 PM
Mochinist,

The best I can do is a link to Dormer.


<font face="Verdana, Arial" size="2">

End Mills For profile milling and producing open slots where a plunge feed is not required

Slot Drills For producing precision slots and keyways, they are centre cutting and can plunge feed to produce closed slots or pockets

3 flute Slot Drills These combine the roles of the slot drill and the end mill, enabling greater productivity than a 2-flute slot drill, due to the additional tooth.

Ball Nosed Slot Drills Designed to produce slots and profiles with a radius form

Roughing Cutters Designed for applications where rapid metal removal is required. The sinusoidal chipbreaker profile is for general roughing, whilst the truncated chipbreaker profile is for roughing where a better quality finish is required.
</font>

You will note that they differentiate between a end mill cutter and a slot drill. They aren't the same.

http://www.dormertools.com/

To properly cut at the centre the flutes must not meet at the centre.

[This message has been edited by Evan (edited 06-18-2005).]

Norman Atkinson
06-18-2005, 02:48 PM
I should stress to one and all that I didn't write the original comments of the late George Thomas nor was I going to infringe the copyright by expanding the remarks into the detail necessary.It is up to our friend to read the varied comments and find his own coefficient for things.
No doubt, he will have a bash at both the end mills and the slot drills and reach his own conclusions.

It would suggest that he has already been nibbled by rats and that the slot drill is the next tool to try.

I have , however, read and re-read the regrinding instructions for end mills and slot drills in the Operating Instructions for the Clarkson tool and cutter grinders.
What does come out, is that Clarksons made both types of drill.

The classic question is why?
Perhaps Mochinist can supply the information. I cannot!

Norman

Timleech
06-18-2005, 03:00 PM
<font face="Verdana, Arial" size="2">Originally posted by mochinist:
Bull I have made thousand's of slots with endmills and they look just fine.</font>


But were they made with a cutter the same width as the slot, and if so how accurate was the width? Yes you can do nice slots with an endmill if you can cut the two sides of the slot in separate passes. Surely the main point of the 2-flute slot drill is that the forces balance out, there's little or no sideways force on the cutter *at the point where it's cutting the sides of the slot*. That's not the case with anything other than a 2-flute cutter. Think about it. Also the asymmetric end allows plunge cutting. It's the proper tool for keyways, and for slots where the slot is the same width as the cutter. Accept no substitute.
OK, I know there are situations where a horizontal cutter will do as well or better, but I don't think that option is open to the OP.

Tim

mochinist
06-18-2005, 03:50 PM
<font face="Verdana, Arial" size="2">Originally posted by Evan:
Mochinist,

The best I can do is a link to Dormer.

You will note that they differentiate between a end mill cutter and a slot drill. They aren't the same.

http://www.dormertools.com/

To properly cut at the centre the flutes must not meet at the centre.

[This message has been edited by Evan (edited 06-18-2005).]</font>


I realize the one in your pic doesnt meet in the center, and you state that is why you can plunge cut with them. I use two flute endmills that are center cutting(the flutes meet in the center) and designed to plunge.

I used google to the best of my ability and from what I gather slot drill is basically the samething as a center cutting endmill. I honestly don't know if their is a differance or not, I did find that alot of the slot drills had threads on one end which I have never seen before.

mochinist
06-18-2005, 04:04 PM
<font face="Verdana, Arial" size="2">Originally posted by NORMAN ATKINSON:
I should stress to one and all that I didn't write the original comments of the late George Thomas nor was I going to infringe the copyright by expanding the remarks into the detail necessary.It is up to our friend to read the varied comments and find his own coefficient for things.
No doubt, he will have a bash at both the end mills and the slot drills and reach his own conclusions.

It would suggest that he has already been nibbled by rats and that the slot drill is the next tool to try.

I have , however, read and re-read the regrinding instructions for end mills and slot drills in the Operating Instructions for the Clarkson tool and cutter grinders.
What does come out, is that Clarksons made both types of drill.

The classic question is why?
Perhaps Mochinist can supply the information. I cannot!

Norman

</font>

Well with out seeing and actually using his setup I can't give a definite answer as to why, but I will take a guess. If I was doing it and I wanted the best possible slot I would use a 5/32 endmill for the whole job, mill the slot to full length and then take a .010 and then a .0055 on each side, climb cutting for the finish cuts. He mentioned using 500 rpm and that is way too slow, I would go with 2000 off the top of my head and adjut as necessary. I would also use a mister(not in a apt though) or use some cutting oil. He also said that when he tried stepping it down that the bottom of the slot was off by 1/32, if I understand that right it sounds like his head isn't trammed in correctly.

mochinist
06-18-2005, 04:12 PM
<font face="Verdana, Arial" size="2">Originally posted by Timleech:

But were they made with a cutter the same width as the slot, and if so how accurate was the width? Yes you can do nice slots with an endmill if you can cut the two sides of the slot in separate passes. Surely the main point of the 2-flute slot drill is that the forces balance out, there's little or no sideways force on the cutter *at the point where it's cutting the sides of the slot*. That's not the case with anything other than a 2-flute cutter. Think about it. Also the asymmetric end allows plunge cutting. It's the proper tool for keyways, and for slots where the slot is the same width as the cutter. Accept no substitute.
OK, I know there are situations where a horizontal cutter will do as well or better, but I don't think that option is open to the OP.

Tim</font>

So you are telling me that these magic slot drills will cut a perfect 3/16 slot 3/8 deep in brass? I would like to see that, I personnaly dont believe it. I use two flute endmills two cut keyways and the key fits nice and snug in the slot. I wouldn't call the finish exceptable though if it was not going to be covered by a key.

Timleech
06-18-2005, 04:51 PM
<font face="Verdana, Arial" size="2">Originally posted by mochinist:
So you are telling me that these magic slot drills will cut a perfect 3/16 slot 3/8 deep in brass? </font>

That wasn't quite what I said. I was just trying to make the point as to why a 'proper' slot drill has only 2 flutes.

Tim

Norman Atkinson
06-18-2005, 06:12 PM
George thomas refered to the end mill cutting the wall ( of the slot) with no 1 tooth which would force the cutter over sideways- but in the opposite direction- with the result of no2 tooth digging into the adjacent wall.This is summarises quite a description but it concludes with the cutter making a slot of up to between 10 and 30 thous oversize.

He does point out that in the absence of a 1/2 slot drill, a 7/16 mill drill could be put through first- followed by the 1/2"
Respectfully, this is what Mochinist is doing.
However, Thomas goes on to suggest that one slotdrill would do the job with less effort.

Again, I have avoided running into copyright issues- I hope.
The full description complete with diagrams does run to 3 pages,

I hope that O2 will appreciate the wide range of expertise- and differences of opinion- which is part and parcel of this Forum. Our little squabbles provide a learning platform for all of us.

Norman

O2
06-18-2005, 06:12 PM
I had started at about 1000 rpm but got a lot of chatter, and I had read that to eliminate chatter you decrese speed and increse feed.

As soon as I get a dial indicator I'll check the tram of my mill head. Just using a 3" square it seems to be pretty straight but that doesn't mean it is.

mochinist
06-18-2005, 06:29 PM
<font face="Verdana, Arial" size="2">Originally posted by NORMAN ATKINSON:

George thomas refered to the end mill cutting the wall ( of the slot) with no 1 tooth which would force the cutter over sideways- but in the opposite direction- with the result of no2 tooth digging into the adjacent wall.This is summarises quite a description but it concludes with the cutter making a slot of up to between 10 and 30 thous oversize.

He does point out that in the absence of a 1/2 slot drill, a 7/16 mill drill could be put through first- followed by the 1/2"
Respectfully, this is what Mochinist is doing.
However, Thomas goes on to suggest that one slotdrill would do the job with less effort.

Again, I have avoided running into copyright issues- I hope.
The full description complete with diagrams does run to 3 pages,

I hope that O2 will appreciate the wide range of expertise- and differences of opinion- which is part and parcel of this Forum. Our little squabbles provide a learning platform for all of us.

Norman</font>


Hey squabbles are good as long as they don't get out of hand.

And as how I would do the slot I wouldn't switch the 7/16 endmill out, I would just move it over the appropiate dimension eachway to get my half inch slot. The only real reason to switch over to the 1/2 endmill would be if the print called for a 1/4 radius at the end of the slot.

JCHannum
06-18-2005, 06:51 PM
Slot drill is a British term that equates to the US center cutting two flute end mill. Whether the end flutes are symmetrical or assymetrical has nothing to do with the function or performance. It is merely different manufacturing practices.

here is a photo of four end mills;
http://members.aol.com/jchannum/mill

From left to right, a four flute, non center cutting, a four flute center cutting and two two flute center cutting. The non center cutting cannot be used to plunge cut as the pip in the center will not remove metal and it will bind. The other three can be used to plunge cut and will mill a slot to size if used properly.

No US reference that I know of, Machinery's Handbook, Moltrecht, Colvin & Stanley or any others use the term slot drill when referring to an end mill.

JRouche
06-18-2005, 07:46 PM
The slot drill looks like a two flute end mill. The face or end flutes are offset so plunge milling is possible.

With standard two flute end mills the flutes are symmetrical but meet in the center providing a cutting edge for the entire face.

The slot drill just looks like a proprietary grind (offset flutes on the face) from one manufacture (Dormer).

Does any other end mill manufacture make slot drills?
JRouche

Mcgyver
06-18-2005, 08:04 PM
I confess to the same results as Geo. Thomas and end up cutting the slot with a narrower cutter and finishing cuts of 10 thou or so on each side, using a bit of air so the chip are getting squashed in seem to matter whether its 4there. btw, when doing so it doesn't matter if its 2 or 4 flutes.

this is a also a better approach as I find the the end mill will tend to get defected off course a little bit from the cutting force so the finish cut on each side cleans things up and restores accuracy.

I never really paid attention to the two vs four - if you use a slot drill, can you expect to get an accurate neat cut without all the about hassle?

[This message has been edited by Mcgyver (edited 06-18-2005).]

John Stevenson
06-18-2005, 08:34 PM
Let me try to expain about end mills and slot drills. Many people have their own description of these but I'm afraid no one is right any longer - even me !!!
First off lets go back in history and see what we had. There were 4 flute end mills and 2 flute end mills. Some could plunge some couldn't. Confused? well you will be.
The two flute ones were called slot drills in the UK and were ground with one cutting edge over centre so they can plunge cut vertically down and then traverse, hence the name. These are the ones on the right in JCHannum's picture.
The 4 flute end mills usually had a hole in the centre for clearance when grinding and so can only cut on the sides of the tool. Trying to plunge with one of these will leave a central pip that will break the cutter when you try to traverse.
Now when we got towards the end of the 20th century things started changing. We had better methods of producing cutters with fancy 5 and 6 axis CNC grinders. We started to see 3 flute cutters getting popular as a compromise between rapid metal removal and chip clearance. We also started to get the 3 and 4 flute cutters with one lip ground over centre like the two flute in the picture. This means that these can also plunge.
To cap it all the manufacturers put paid to any standards by calling their cutters all sorts of different names. Where a 4 flute cutter was called an end mill it can now be centre cutting and be called a 4 flute slot drill.
If you look in any cutter catalogue nowdays you will find that they call a certain type of cutter by one name on one page and another manufacturer calls it by a different name on another page! The manufacturers have moved the goalposts. The cutter descriptions we all grew up with in Chapmans and Moultreich &lt;sp&gt; has gone out the window with the advent of grinding techniques.
I took a 20mm solid carbide 4 flute end mill [ non centre cutting ] in for regrind last month and when it came back it was 4 flute over centre slot cutting cutter. What do I call this now?
The main thing to look for when buying cutters is the number of flutes you require and whether they are centre cutting or not.
I can see the time when the old 4 flute centre pipped type will become obsolete as most cutters are ground up from blank material nowdays.
I had a load of cam track slots to do the other week at 7.2mm wide. I had a choice of doing two passes with an undersized cutter or having a cutter ground down to 7.2mm
I decided to go with the special cutter and asked the local T&C grinders to supply and regrind an 8mm cutter down. Instead they just ground the new cutter straight onto a 8mm solid blank, 3 flute centre cutting. It was on the machine for all of 3 minutes.

John S.



[This message has been edited by John Stevenson (edited 06-18-2005).]

PSD KEN
06-18-2005, 08:50 PM
http://www.newmantools.com/endmills/4500.htm

happy02
06-18-2005, 11:32 PM
I prefer to use side cutters like woodruff keyseat cutters or slotting or slitting saws for this work. A 3/16" keyseat cutter probably won't get 3/8" deep cut tho. The setup would be to clamp the part directly to the mill table and indicate down to the center and slot.
If milling I would use a 2 Flute center cutting end mill by whatever name. I would take light cuts and mill the full length. The 2 flute end mill will have less tendancy to walk than a 4 flute. At least that is my experience.
I would also run the 3/16" end mill at around 1100 rpm or better. Small mills and drills should be ran faster than larger ones.

[This message has been edited by happy02 (edited 06-18-2005).]

J Tiers
06-18-2005, 11:32 PM
I'm just a dummy, but I gotta say I have done as mochinist says..... cut the slot with an end mill. Any end mill that was smaller than the slot.

But, doing it in one pass has not been good, two passes or better three has been best with small-diameter end mills. They do deflect at the 0.125 size, and while the slot may look pretty straight, a piece of keystock may say they aren't.

example being cut. Its an arbor for the mill. I see I was using a 2 flute cutter, but I had used a 4 flute for the smaller keyway on teh near side. A 1.250 arbor, needed a 0.187 slot and a larger one, both.

Would have used a regular milling cutter, but needed to stop at the shoulder, and reach to it.

http://img.photobucket.com/albums/0803/jstanley/arb15mil.jpg



[This message has been edited by J Tiers (edited 06-18-2005).]

O2
06-19-2005, 01:03 AM
I don't mind the squabbling at all, its a whole lot more polite than on some of the boards I frequent and a whole lot more informative. I think I've learned more about milling from this thread that I learned from a couple of the books I've bought.

I'm definitely going to try the 2 flute cutter. I don't have a 1/8", only a 3/16" and 1/4".

I will say that for all the frustration I've gotten trying to mill these slots, its really awesome working with metal again.

If theres any life left in this discussion, I sure will keep up with it. I'm glad I found this board.

Norman Atkinson
06-19-2005, 01:21 AM
O2, I am sure that John is right- as ever!

Unquestionably, he is like the man who pee on weighing machine, does business on big scale. His comments bring milling into the new century.

I'm just an "old fashioned millionaire"- and a bit of a stick in the mud. Nevertheless, I feel that my advice is to use what we call slot drills in preference to end mills for slotting. If there is something better- as John rightly suggests-
it is worthy of consideration.

Actually, I was sitting with the old book on tool and cutter grinding from the Clarkson factory- and the date was April 1968.

Guilty as Hell, me lud!

Norman

Evan
06-19-2005, 02:01 AM
Don't give me that luddite crap Norman. http://bbs.homeshopmachinist.net//biggrin.gif

The slot drill such as the one I have shown is not just a Dormer proprietary grind. It is a superior tool for cutting a slot, especially a blind slot. John as usual has illuminated the situation with black light... http://bbs.homeshopmachinist.net//biggrin.gif

The slot drill as made that I use cuts a slot that is accurate to a thou or so in one pass. You can see that it is clearly a very clean slot.

As I said before, it seems that the US doesn't always have easy access to the best technology. The reasons have nothing to do with what works best for the job but are usually tied up in politics or backward economics, just like the Roberson screw.

Norman Atkinson
06-19-2005, 02:31 AM
For once, Evan, on this fine English Sunday morning, I was reading St Paul- the tent maker fellow.

In Ephesians, he says
"see that ye walk circumspectly"

and in Thessalonians , he says
" Prove all things; hold to that which is good"

and Shakespeare writes for those screwcutters

" This is the top, the height, the crest or crest unto the crest"
King John.

For those who tilt at windmills?
Cervantes quotes little Sacho Panza:-
"All men are as God made them, and very often worse"

And Luddites to you, matey!I've never broken a machine yet- but slot drills and end mills? Well, modesty forbids.

Norman

[This message has been edited by NORMAN ATKINSON (edited 06-19-2005).]

Evan
06-19-2005, 02:49 AM
Norman, it is just barely Sunday here too. I too have never broken a machine intentionally.

This is apropo of nothing but it is one of my favorite poems.

Once upon a midnight dreary, while I pondered weak and weary,
Over many a quaint and curious volume of forgotten lore,
While I nodded, nearly napping, suddenly there came a tapping,
As of some one gently rapping, rapping at my chamber door.
`'Tis some visitor,' I muttered, `tapping at my chamber door -
Only this, and nothing more.'

Ah, distinctly I remember it was in the bleak December,
And each separate dying ember wrought its ghost upon the floor.
Eagerly I wished the morrow; - vainly I had sought to borrow
From my books surcease of sorrow - sorrow for the lost Lenore -
For the rare and radiant maiden whom the angels named Lenore -
Nameless here for evermore.

And the silken sad uncertain rustling of each purple curtain
Thrilled me - filled me with fantastic terrors never felt before;
So that now, to still the beating of my heart, I stood repeating
`'Tis some visitor entreating entrance at my chamber door -
Some late visitor entreating entrance at my chamber door; -
This it is, and nothing more,'

Presently my soul grew stronger; hesitating then no longer,
`Sir,' said I, `or Madam, truly your forgiveness I implore;
But the fact is I was napping, and so gently you came rapping,
And so faintly you came tapping, tapping at my chamber door,
That I scarce was sure I heard you' - here I opened wide the door; -
Darkness there, and nothing more.

Deep into that darkness peering, long I stood there wondering, fearing,
Doubting, dreaming dreams no mortal ever dared to dream before
But the silence was unbroken, and the darkness gave no token,
And the only word there spoken was the whispered word, `Lenore!'
This I whispered, and an echo murmured back the word, `Lenore!'
Merely this and nothing more.

Back into the chamber turning, all my soul within me burning,
Soon again I heard a tapping somewhat louder than before.
`Surely,' said I, `surely that is something at my window lattice;
Let me see then, what thereat is, and this mystery explore -
Let my heart be still a moment and this mystery explore; -
'Tis the wind and nothing more!'

Open here I flung the shutter, when, with many a flirt and flutter,
In there stepped a stately raven of the saintly days of yore.
Not the least obeisance made he; not a minute stopped or stayed he;
But, with mien of lord or lady, perched above my chamber door -
Perched upon a bust of Pallas just above my chamber door -
Perched, and sat, and nothing more.

Then this ebony bird beguiling my sad fancy into smiling,
By the grave and stern decorum of the countenance it wore,
`Though thy crest be shorn and shaven, thou,' I said, `art sure no craven.
Ghastly grim and ancient raven wandering from the nightly shore -
Tell me what thy lordly name is on the Night's Plutonian shore!'
Quoth the raven, `Nevermore.'

Much I marvelled this ungainly fowl to hear discourse so plainly,
Though its answer little meaning - little relevancy bore;
For we cannot help agreeing that no living human being
Ever yet was blessed with seeing bird above his chamber door -
Bird or beast above the sculptured bust above his chamber door,
With such name as `Nevermore.'

But the raven, sitting lonely on the placid bust, spoke only,
That one word, as if his soul in that one word he did outpour.
Nothing further then he uttered - not a feather then he fluttered -
Till I scarcely more than muttered `Other friends have flown before -
On the morrow will he leave me, as my hopes have flown before.'
Then the bird said, `Nevermore.'

Startled at the stillness broken by reply so aptly spoken,
`Doubtless,' said I, `what it utters is its only stock and store,
Caught from some unhappy master whom unmerciful disaster
Followed fast and followed faster till his songs one burden bore -
Till the dirges of his hope that melancholy burden bore
Of "Never-nevermore."'

But the raven still beguiling all my sad soul into smiling,
Straight I wheeled a cushioned seat in front of bird and bust and door;
Then, upon the velvet sinking, I betook myself to linking
Fancy unto fancy, thinking what this ominous bird of yore -
What this grim, ungainly, gaunt, and ominous bird of yore
Meant in croaking `Nevermore.'

This I sat engaged in guessing, but no syllable expressing
To the fowl whose fiery eyes now burned into my bosom's core;
This and more I sat divining, with my head at ease reclining
On the cushion's velvet violet lining that the lamp-light gloated o'er,
But whose velvet violet lining with the lamp-light gloating o'er,
She shall press, ah, nevermore!

Then, methought, the air grew denser, perfumed from an unseen censer
Swung by Seraphim whose foot-falls tinkled on the tufted floor.
`Wretch,' I cried, `thy God hath lent thee - by these angels he has sent thee
Respite - respite and nepenthe from thy memories of Lenore!
Quaff, oh quaff this kind nepenthe, and forget this lost Lenore!'
Quoth the raven, `Nevermore.'

`Prophet!' said I, `thing of evil! - prophet still, if bird or devil! -
Whether tempter sent, or whether tempest tossed thee here ashore,
Desolate yet all undaunted, on this desert land enchanted -
On this home by horror haunted - tell me truly, I implore -
Is there - is there balm in Gilead? - tell me - tell me, I implore!'
Quoth the raven, `Nevermore.'

`Prophet!' said I, `thing of evil! - prophet still, if bird or devil!
By that Heaven that bends above us - by that God we both adore -
Tell this soul with sorrow laden if, within the distant Aidenn,
It shall clasp a sainted maiden whom the angels named Lenore -
Clasp a rare and radiant maiden, whom the angels named Lenore?'
Quoth the raven, `Nevermore.'

`Be that word our sign of parting, bird or fiend!' I shrieked upstarting -
`Get thee back into the tempest and the Night's Plutonian shore!
Leave no black plume as a token of that lie thy soul hath spoken!
Leave my loneliness unbroken! - quit the bust above my door!
Take thy beak from out my heart, and take thy form from off my door!'
Quoth the raven, `Nevermore.'

And the raven, never flitting, still is sitting, still is sitting
On the pallid bust of Pallas just above my chamber door;
And his eyes have all the seeming of a demon's that is dreaming,
And the lamp-light o'er him streaming throws his shadow on the floor;
And my soul from out that shadow that lies floating on the floor
Shall be lifted - nevermore!

Norman Atkinson
06-19-2005, 07:10 AM
What a delight to read a nice bit of verse.
It must be the little brown Celts- Evan Williams- look you! The Bard of Borland Street. They have, my Welsh Wizard, the Gift- or as we say- are Fey. The gift of the Second Sight.

How on earth did you choose the bit on the Raven? I married a Liddell of Ravensworth Castle. My lodge is Ravensworth and Alice of Alice in Wonderland is actually Alice Pleasance Liddell- or Hargreaves on marriage.

You will be able to solve the riddle of Why is the Raven Like a Writing Desk.

How amazingly perceptive.

Norman

chief
06-19-2005, 07:11 AM
I can't believe that for 35 years I have been milling slots wrong, Tomorrow I am throwing away all those useless endmills
and getting slotting drills.
Two pages about how to do a five minute job.

Norman Atkinson
06-19-2005, 07:21 AM
Sorry, folks!

It was Edgar Allan Poe- The Raven.

Sirius

JCHannum
06-19-2005, 07:58 AM
http://members.aol.com/jchannum/slot

1/4" X 1/8" deep slot, plunge milled one end, one pass at 1/8" depth, 1147 RPM, WD40 coolant. Weldon made in USA two flute center cutting symmetrical end mill, Cat. No B 8-2. Finished slot width 0.2500". Material 6061 aluminum T-6.

Total time to complete, 2 minutes, one of which was spent in finding and installing the end mill.

No matter what some may think, slot mill is just another name as John says. The Dormer end grind is not proprietary, and gives no advantage other than advertising hype. It is not some vastly improved technology that America has not embraced.

John Stevenson
06-19-2005, 08:10 AM
Nice job JC and goes to prove that there is nothing special about it.

Industry is doing this millions of times per day.
If there were a problem it would have been addressed by now by brains greater than our collective ones.

Industry has now moved onto the over centre type cutting mills as opposed to the centre hole of years ago.

If there is a problem in cutting slot the same size as the cutter then look elsewhere other than the cutter.
Spindle bearings, collet or holder run out, rigidity of the setup, in fact rigidity full stop.
Don't expect to do a 1/2" slot in one pass on a mill drill, the machine will be the limiting factor here, not the cutter.

If you are limited by your machine, and lets face it not everyone can have a #7,000 vertical at home, then you have to find a way to work round.

Cuting out with an undersized cutter and then two clean up passes or swap cutters and do an on size cleanup pass or whatever suits.
You just have to learn to live with the limitations you have and work round them.
OK it will be slower but I'm sorry that's the price you pay.

John S.

Timleech
06-19-2005, 01:52 PM
I did a little experiment this afternoon, mainly to satisfy my own curiosity & certainly not to prove a belief, but thought others might be interested in the result.
I was cutting a slot similar to the OP's aim, 3/16" wide x 10mm deep in brass. I did 3 slots, nominally 25mm long. First (right in the pic) was a plunge cut with a 3/16" dia 2-flute slot drill (Call it what you like http://bbs.homeshopmachinist.net//wink.gif )


Middle one was a 3/16" dia 3-flute centre cutting FC3 throwaway endmill.
Left hand slot was a conventional 4-flute 3/16" endmill, not centre cutting hence the open end.

http://web.onetel.com/~duttondock/Pictures/brassslots-1.jpg

All were done with the same setup, dry, nominal 3000 rpm, 25mm/min feed, reasonably rigid machine. All cutters were new or as new, UK made (Osborn/Clarkson)

Measured with decent digital calipers, & the calipers checked with a micrometer, the first, 2-flute cut measured .186". The second, 3-flute, at .188/.1885, and the 4-flute at .189". This was at the bottom of the slots, but no real variation on any of them with depth.
By far the worst finish was with the 3-flute, the others were both pretty good with the 2-flute just marginally the better.
I don't pretend this is scientific, there may be variations in actual cutter sizes etc, plus I had no air on hand to blow away the swarf - finish might have been better if I had. Feed was just a guess at something which wouldn't cause the cutters distress, optimum feeds might also have influenced the result.

Tim

mochinist
06-19-2005, 05:27 PM
Well Thanks for the explanation John S.,I am very happy to know that us dumb Americans have not been missing out on that magically ground slot drill, it seems to be just a different name.

O2
06-19-2005, 10:39 PM
Thanks for showing the experiments! There might still be help for me yet. As soon as there's not little children running around getting into the chips, I'm going to give the 2 flute mills I have a try. Its going to be tricky getting the feed down that slow when I'm hand cranking. Practice makes perfect.