# Slitting saw advice requested.



## DickDastardly40 (Dec 30, 2008)

You know the adage when the only tool you have is a hammer, everything looks like a nail, well my new to me VMC mill arrived (pics to follow) and I am playing.

Where I would have parted something previously, I'd like to use the mill and slit so as to get less waste.

I have never been taught to use a slit saw and bought one on a whim a while ago, so this is it's first tryout.

What formula should I use for speed/feed and what depth of cut is recommended as regards tooth size. Is feeding into the blade (upcut) a la a circular saw verboten as this is essentially climb milling?

Any advice gratefully received even links to previous threads, I've never seen anything written about slitting.

Al


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## BobWarfield (Dec 30, 2008)

Well now here I thought we were all nice people on this board!

Al, how can you casually mention getting a VMC (!!!) and not have the pictures already up!

That's cruel and unusual punishment I tell you. 

<Me walks away in a huff>

BW


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## Mainer (Dec 30, 2008)

Figure feed/speed the same as anything else. Pretend it's a 4" diameter end mill, or whatever the saw diameter is. As a guess, 4" diameter saw will probably want about 100 rpm in steel.

FWIW, I just crank the speed down on my VFD until it's "slow" and feed slowly enough so the saw doesn't bog down. If it seems as though it's "too slow" I crank the speed up until I get nervous. Not very scientific, I'm afraid.


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## Bernd (Dec 30, 2008)

You don't want to climb mill, it'll grab and pull. You'll be doing a quick duck and trying to hit the stop button.

Conventional milling. Always run the slitting saw slower and work your way up. It depends alot on the dia. of the saw as to speed. I'm sure you can use the same formula as is used to find the speed of a mill on the same dia.

bernd


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## joeby (Dec 31, 2008)

FWIW, I run slitter saws without the key, you'll get lots of remarks about that; but I've cracked far more saws using a key than without. As already stated above, speeds/feeds are calculated the same as anything else; but feedrates will seem high because of your tooth count.

 I agree with conventional milling only. You won't be able to control your feed well enough to climb mill, slitter saws won't forgive you if you overfeed.

 I like to take as much on depth of cut as I can, sometimes full depth if the setup permits. Feed very slowly until you're into the cut, the saw teeth will straddle a sharp corner and you can end up with missing teeth from getting too much in "one bite".

 Careful with tubing too, for the above reason. 

Kevin


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## Brian Rupnow (Dec 31, 2008)

Dick--One of us is confused here, On both table saws and hand held circular saws, the wood is fed against the direction of rotation, into the saw. This is not "climb milling" This would equate to conventional milling, where again, the work is fed into the cutting tool, against the rotation. If you fed wood into a table saw from the wrong side of the table, thus "with" the direction of rotation of the saw, it would grab the wood out of your hands and fling it across the room at 5000 miles an hour--same as what will happen with "climb milling" in a manual vertical milling machine. You ALWAYS feed against the rotation of the cutting tool whether it is wood or metal, saw or milling machine.


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## joeby (Dec 31, 2008)

Brian,
 Climb milling is a very common practice for several reasons. It will give you a better finish, and increase tool life among others. Big issue with climb milling is machine condition and rigidity. Some horizontal mills had a setting for climb or conventional milling. I don't like to climb mill even on a Bridgeport unless it's a very light finish pass or soft material (aluminum, plastics, etc.) I do, however, climb mill wherever I can on the CNC mill at work. Ball screws make all the difference there.

Kevin


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## Brian Rupnow (Dec 31, 2008)

joeby  said:
			
		

> Brian,
> Climb milling is a very common practice for several reasons. It will give you a better finish, and increase tool life among others. Big issue with climb milling is machine condition and rigidity. Some horizontal mills had a setting for climb or conventional milling. I don't like to climb mill even on a Bridgeport unless it's a very light finish pass or soft material (aluminum, plastics, etc.) I do, however, climb mill wherever I can on the CNC mill at work. Ball screws make all the difference there.
> 
> Kevin



Kevin--Come to my place some time, and try some climb milling with my small vertical mill. When you leave, your undershorts will not be in the same condition as when you arrived!!! ;D ;D ;D I know that climb milling will leave a smoother surface, and generally I achieve that by backing my work through the revolving cutter without advancing the table. The few times that old age and stupidity overtook me and I climb milled while actually taking a cut, the results were quite spectacular, in a heart stopping kind of way!!!


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## joeby (Dec 31, 2008)

Brian,
 Thank you for the offer; but after working in the tool & die field for almost twenty-five years, I now wear bulletproof undershorts ;D ;D

 Seriously though, I have a full size Bridgeport clone in my shop. I try to avoid climb milling completely on that machine even considering it probably has less than 200 hours on it. I also have a Nichols horizontal mill that is an industrial machine; but I avoid climb milling on it mostly because of the table feed nut being rather weak looking.

 I agree completely though, climb milling isn't for a hobby-type machine in most cases. 

 By the way, I have seen what happens when you climb mill with a 4" diameter, 4" wide slab mill at .250" depth of cut in rapid traverse!  It wasn't me, honest; but I was standing nearby. The Cincinnati mill never even grunted; but the cutter, arbor, and workpiece died instantly!

Kevin


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## speakerme (Dec 31, 2008)

I have a bridgeport clone (Birmingham) and have no problems with climb cutting. But as I was trained, I generally save it for the last finish cuts, since it almost always produces a finer finish. 
also when you cut against the work, why waist the movement back to start without a little climb cut to take off a little more to get to goal.

Best Wishes and Happy New Year

Chuck M


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## baldrocker (Jan 1, 2009)

OK confused newbie time again.
When we refer to climb milling is it the workpiece that climbs over the cutter or
the the cutter that climbs over the workpiece. The reason I ask is that
I have seen conflicting pics/diagrams. 
BR


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## Maryak (Jan 1, 2009)

BR,

The attached picture may clarify things, I hope so anyway

Best Regards
Bob


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## baldrocker (Jan 1, 2009)

So given the rotation of the cutter in 12a one should feed the workpiece
in the other direction to that shown?
BR


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## Maryak (Jan 1, 2009)

baldrocker  said:
			
		

> So given the rotation of the cutter in 12a one should feed the workpiece
> in the other direction to that shown?
> BR



In a word Yes, for conventional/up milling

Best Regards
Bob


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## joeby (Jan 1, 2009)

Chuck,
 Just to clarify, I am talking more along the lines of the OP. Taking a slitter saw through by climb milling on my mill, or any cutter with a reasonable depth of cut, I consider a risky situation. I should have put it that way in my post though.

 Your mill may be of a better quality than mine (Enco); but I knew basically what I was getting when I bought it. It's heavier than a Bridgeport; but it's the stuff you can't immediately see that concerns me. Lots of "pot metal" parts to replace steel and bronze in the real Bridgeport.

 To get back to the original question, slitter saws will do very nicely for parting off work; but not knowing the machine or it's capabilities, I think I would stick to conventional milling at least until I've become familiar with it. In re-reading the original post, I'm not at all sure what type/size machine it is.

Just my $.02.

Happy New Year!

Kevin


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## Mike N (Jan 1, 2009)

Climb milling with large cutters on a milling machine with even a slight amount of backlash is dangerous! I only climb cut with small cutters & take light cuts, the cutter can dig in & rip your part right out the vise leaving some pretty cool pecker tracks across your work piece! + you will break a lot of cutters climb cutting!


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## DickDastardly40 (Jan 2, 2009)

Lots of replies to my original post, thanks very much!

I'll read them all later and try the suggestions and will feedback.

Thanks again

Al


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## Hilmar (Jan 2, 2009)

Al,
 Do a search for cut off or slitting saw. There should be a few post with pix on that in the files.I know , I posted some.
Hilmar  	
P.S. go to
Engines From Castings

Re: A Stuart Turner Triple Expansion Engine 
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